We address the question whether the magneto-rotational instability (MRI) can operate in the near-surface shear layer (NSSL) of the Sun and how it affects the interaction with the dynamo process. Using hydromagnetic mean-field simulations of $αΩ$-type dynamos in rotating shearing-periodic boxes, we show that for negative shear, the MRI can operate above a certain critical shear parameter. This parameter scales inversely with the equipartition magnetic field strength above which $α$ quenching set in. Like the usual $Ω$ effect, the MRI produces toroidal magnetic field, but in our Cartesian cases it is found to reduce the resulting magnetic field strength and thus to suppress the dynamo process. In view of the application to the solar NSSL, we conclude that the turbulent magnetic diffusivity may be too large for the MRI to be excited and that therefore only the standard $Ω$ effect is expected to operate.
Dark matter (DM) particles can interact with particles of the Standard Model. Although there exist constraints from direct and indirect detection experiments, the dynamical evolution of astrophysical objects could provide a promising probe for these interactions. Obtaining astrophysical predictions is challenging and limited by our ability to simulate scatterings between DM and baryonic particles within N-body and hydrodynamics simulations. We develop a novel scheme that allows simulating these interacting dark matter (IDM) models and accurately accounts for their angular and velocity dependence, as well as the mass ratio between the DM and baryonic scattering partners. To describe DM-baryon interactions, we use an N-body code together with its implementation of smoothed-particle hydrodynamics and meshless finite mass. The interaction itself is realised in a pairwise fashion by creating a virtual scattering partner from the baryonic particle and letting it interact with a DM particle using a scattering routine initially developed for self-interacting dark matter. After the interaction, the virtual particle is rejoined with the baryonic particle, fulfilling energy and momentum conservation. Through several test problems, we demonstrate that we can reproduce their analytic solutions with our IDM scheme. We comment on various numerical aspects and challenges as well as describe the limitations of our numerical scheme. Furthermore, we study the impact of IDM on halo formation with a collapsing overdensity. Overall, it is possible to accurately model IDM within N-body and hydrodynamics simulations, commonly used in astrophysics. In consequence, our scheme allows for making novel predictions and obtaining new constraints of DM-baryon scattering.
The self-organization of proteins into enriched compartments and the formation of complex patterns are crucial processes for life on the cellular level. Liquid-liquid phase separation is one mechanism for forming such enriched compartments. When phase-separating proteins are membrane-bound and locally disturb it, the mechanical response of the membrane mediates interactions between these proteins. How these membrane-mediated interactions influence the steady state of the protein density distribution is thus an important question to investigate in order to understand the rich diversity of protein and membrane-shape patterns present at the cellular level. This work starts with a widely used model for membrane-bound phase-separating proteins. We numerically solve our system to map out its phase space and perform a careful, systematic expansion of the model equations to characterize the phase transitions through linear stability analysis and free energy arguments. We observe that the membrane-mediated interactions, due to their long-range nature, are capable of qualitatively altering the equilibrium state of the proteins. This leads to arrested coarsening and length-scale selection instead of simple demixing and complete coarsening. In this study, we unambiguously show that long-range membrane-mediated interactions lead to pattern formation in a system that otherwise would not do so. This work provides a basis for further systematic study of membrane-bound pattern-forming systems.
In the presence of a weak gravitational wave (GW) background, astrophysical binary systems act as high-quality resonators, with efficient transfer of energy and momentum between the orbit and a harmonic GW leading to potentially detectable orbital perturbations. In this work, we develop and apply a novel modeling and analysis framework that describes the imprints of GWs on binary systems in a fully time-resolved manner to study the sensitivity of lunar laser ranging, satellite laser ranging, and pulsar timing to both resonant and nonresonant GW backgrounds. We demonstrate that optimal data collection, modeling, and analysis lead to projected sensitivities which are orders of magnitude better than previously appreciated possible, opening up a new possibility for probing the physics-rich but notoriously challenging to access $μ\mathrm{Hz}$ frequency GWs. We also discuss improved prospects for the detection of the stochastic fluctuations of ultra-light dark matter, which may analogously perturb the binary orbits.
The ultra-hot Jupiter (UHJ) TOI-2109b marks the lower edge of the equilibrium temperature gap between 3500 K and 4500 K, an unexplored thermal regime that separates KELT-9b, the hottest planet yet discovered, from all other currently known gas giants. To study the structure of TOI-2109b's atmosphere, we obtained high-resolution emission spectra of both the planetary day- and nightsides with CARMENES and CRIRES$^+$. By applying the cross-correlation technique, we identified the emission signatures of Fe I and CO, as well as a thermal inversion layer in the dayside atmosphere; no significant H$_2$O signal was detected from the dayside. None of the analyzed species were detectable from the nightside atmosphere. We applied a Bayesian retrieval framework that combines high-resolution spectroscopy with photometric measurements to constrain the dayside atmospheric parameters and derive upper limits for the nightside hemisphere. The dayside thermal inversion extends from 3200 K to 4600 K, with an atmospheric metallicity consistent with that of the host star (0.36 dex). Only weak constraints could be placed on the C/O ratio ($>$ 0.15). The retrieved spectral line broadening is consistent with tidally locked rotation, indicating the absence of strong dynamical processes. An upper temperature limit of 2400 K and a maximum atmospheric temperature gradient of 700 K/log bar could be derived for the nightside. Comparison of the retrieved dayside T-p profile with theoretical models, the absence of strong atmospheric dynamics, and significant differences in the thermal constraints between the day- and nightside hemispheres suggest a limited heat transport efficiency across the planetary atmosphere. Overall, our results place TOI-2109b in a transitional regime between the UHJs below the thermal gap, which show both CO and H$_2$O emission lines, and KELT-9b, where molecular features are largely absent.
We update the Standard Model (SM) predictions for the lifetimes of the B+, Bd and Bs mesons within the heavy quark expansion (HQE), including the recently determined NNLO-QCD corrections to non-leptonic decays of the free b-quark. In addition, we update the HQE predictions for the lifetime ratios τ (B+)/τ (Bd) and τ (Bs)/τ (Bd), and provide new results for the semileptonic branching fractions of the three mesons entirely within the HQE. We obtain a considerable improvement of the theoretical uncertainties, mostly due to the reduction of the renormalisation scale dependence when going from LO to NNLO, and for all the observables considered, we find good agreement, within uncertainties, between the HQE predictions and the corresponding experimental data. Our results read, respectively, Γ(B+) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.587</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.035</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.025</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps‑1, Γ(Bd) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.636</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.037</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.028</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps‑1, Γ(Bs) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.628</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.035</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.027</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps‑1, for the total decay widths, τ (B+)/τ (Bd) = <inline-formula><mml:math><mml:msubsup><mml:mn>1.081</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.016</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.014</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>, τ (Bs)/τ (Bd) = <inline-formula><mml:math><mml:msubsup><mml:mn>1.013</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.007</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.007</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>, for the lifetime ratios, and <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msup><mml:mi>B</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>11.46</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.32</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.47</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msub><mml:mi>B</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>10.57</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.27</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.47</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msub><mml:mi>B</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>10.52</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.29</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.50</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, for the semileptonic branching ratios. Finally, we also provide an outlook for further improvements of the HQE determinations of the B-meson decay widths and of their ratios.
The M-theoretic emergence proposal claims that in an isotropic decompactification limit to M-theory the full effective action is generated via quantum effects by integrating out only the light towers of states of the theory. In the BPS particle sector, these include transversally wrapped $M2$- and $M5$-branes possibly carrying Kaluza-Klein momentum. This implies that a longitudinally wrapped $M5$-brane, i.e. a wrapped $D4$-brane, is not to be included in emergence computations. In this work we collect explicit evidence supporting this point by examining an $F^4$ gauge coupling in six dimensions, making use of the duality between heterotic string theory on $T^4$ and strongly coupled type IIA on K3. In this instance, the M-theoretic emergence proposal can be viewed as a tool for making predictions for the microscopic behavior of string theoretic amplitudes.
We compute differential distributions for Drell–Yan processes at the LHC and the Tevatron colliders at next-to-next-to-leading order in perturbative QCD, including fiducial cuts on the decay leptons in the final state. The comparison of predictions obtained with four different codes shows excellent agreement, once linear power corrections from the fiducial cuts are included in those codes that rely on phase-space slicing subtraction schemes. For Z-boson production we perform a detailed study of the symmetric cuts on the transverse momenta of the decay leptons. Predictions at fixed order in perturbative QCD for those symmetric cuts, typically imposed in experiments, suffer from an instability. We show how this can be remedied by an all-order resummation of the fiducial transverse momentum spectrum, and we comment on the choice of cuts for future experimental analyses.
In this paper, the first in a series, we present a new theoretical model for the global structure and dissipation of relativistically magnetized collisionless shock waves. Quite remarkably, we find that in contrast to unmagnetized shocks, the leading energy dissipation channel does not involve collective plasma interactions. Rather, it is a consequence of nonlinear particle dynamics. We demonstrate that the kinetic-scale shock transition can be modeled as a stationary system consisting of a large set of cold beams coupled through the magnetic field. The fundamental mechanism governing shock dissipation relies on the onset of chaos in orbital dynamics within quasiperiodic solitonic structures. We discuss the impact of upstream temperature and magnetization on the shock profile, recovering the magnetic field compression, downstream velocities, and heating expected from the Rankine-Hugoniot jump conditions. We deduce a rate of entropy generation from the spectrum of Lyapunov exponents and discuss the thermalization of the beam distribution. Our model provides a general framework to study magnetized collisionless shock structures.
The authors present a new method to analytically prove global stability in ghost‑ridden dynamical systems. The proposal encompasses all prior results and consequentially extends them. In particular, it is shown that stability can follow from a conserved quantity that is unbounded from below, contrary to expectation. Novel examples illustrate all of the results. The findings take root on a careful examination of the literature, here comprehensively reviewed for the first time. This work lays the mathematical basis for ulterior extensions to field theory and quantization, and it constitutes a gateway for inter‑disciplinary research in dynamics and integrability.
Quasi-periodic eruptions (QPEs) are rapid, recurring X-ray bursts from supermassive black holes, believed to result from interactions between accretion disks and surrounding matter. The galaxy SDSS1335+0728, previously stable for two decades, exhibited an increase in optical brightness in December 2019, followed by persistent active galactic nucleus (AGN)-like variability for 5 yr, suggesting the activation of a ~106-M⊙ black hole. Since February 2024, X-ray emission has been detected, revealing extreme ~4.5-d QPEs with high fluxes and amplitudes, long timescales, large integrated energies and a ~25-d superperiod. Low-significance UV variations are reported, probably related to the long timescales and large radii from which the emission originates. This discovery broadens the possible formation channels for QPEs, suggesting that they are linked not solely to tidal disruption events but more generally to newly formed accretion flows, which we are witnessing in real time in a turn-on AGN candidate.
The Standard Model extended by a real scalar singlet S with an approximate ℤ2 symmetry offers a minimal framework for realizing electroweak baryogenesis (EWBG) during a first-order electroweak phase transition. In this work, we explore a novel mechanism where spontaneous ℤ2 breaking enables EWBG via domain walls separating two distinct phases of the S field. These domain walls feature restored (or weakly broken) EW symmetry in their cores and sweep through space, generating the baryon asymmetry below the temperature of EW symmetry breaking. We identify the key conditions for the existence of EW-symmetric domain wall cores and analyze the dynamics required for wall propagation over sufficient spatial volumes. Additionally, we outline the CP-violating sources necessary for baryogenesis under different regimes of domain wall evolution. The parameter space accommodating this mechanism spans singlet masses from sub-eV to 15 GeV, accompanied by a non-vanishing mixing with the Higgs boson. Unlike the standard realization of EWBG in the minimal singlet-extended SM, which is notoriously difficult to test, our scenario can be probed by a wide range of existing and upcoming experiments, including fifth force searches, rare meson decays, and EDM measurements.
Galaxy chemical enrichment mechanisms have primarily been constrained by [α/Fe] and [Fe/H] measurements of individual stars and integrated light from stellar populations. However, such measurements are limited at higher redshifts (z > 1). Recently, we proposed an analogous diagram of the oxygen-to-argon abundance ratio, log(O/Ar), versus Ar abundance, 12+log(Ar/H), as a new diagnostic window for emission nebulae. In this Letter, using line flux measurements including temperature-sensitive auroral lines, we present direct determination of O and Ar abundances in nine star-forming galaxies (SFGs) from JWST/NIRSPEC spectra at z ∼ 1.3–7.7 and two more with Keck/MOSFIRE spectra at z ∼ 2.2. Utilizing their positions on the log(O/Ar) versus 12+log(Ar/H) plane, we present the first inference of galaxy chemical enrichment mechanisms from an ensemble of galaxies. Seven SFGs at z ∼ 1.3–4 are consistent with the Milky Way solar neighborhood galactic chemical enrichment models that are driven by core-collapse and Type Ia supernovae in a self-regulated manner. Such enrichment mechanisms thus occur at least out to z ∼ 4. However, four higher-redshift SFGs (z ∼ 3.6–7.7) have lower log(O/Ar) values, revealing potentially different enrichment paths becoming important at z > 3.6. Such log(O/Ar) values may be caused by physical mechanisms such as rapid but intermittent star formation and/or additional enrichment sources. This new diagnostic window for SFGs enables us to reveal the unique fingerprints of galaxy chemical enrichment out to cosmic dawn.
This paper presents a quantitative analysis of the stellar content in the Local Group dwarf irregular galaxy NGC 6822 by comparing stellar evolution models and observations in color–magnitude diagrams (CMDs) and color–color diagrams (CC-Ds). Our analysis is based on optical ground-based g, r, i photometry, and deep archival Hubble Space Telescope photometry of two fields in the galactic disk. We compared young, intermediate-age, and old stellar populations with isochrones from the BaSTI-IAC library and found that NGC 6822 hosts a quite metal-rich ([Fe/H] = ‑0.7 to ‑0.4) young component with an age ranging from 20–100 Myr. The intermediate-age population experienced a modest chemical enrichment between 4 and 8 Gyr ago, while stars older than 11 Gyr have a low metal abundance ([Fe/H] ∼ ‑1.70). We also identified the asymptotic giant branch (AGB) clump population with a luminosity peak at i ∼ 23.35 mag. Our analysis of both the CMD and the optical–near-IR (NIR)–mid-IR (MIR) CC-Ds of AGB oxygen- and carbon-rich stars, using the PARSEC+COLIBRI isochrones with and without circumstellar dust, reveals that this stellar component exhibits a spread in age from 1–2 Gyr and in metallicity between [Fe/H] = ‑1.30 and ‑1.70. The stellar models we used reproduce very well the two distinct color sequences defined by AGB O- and C-rich stars in the various optical–NIR–MIR CC-Ds, suggesting that they are reliable diagnostics to identify and characterize intermediate-age stellar populations. However, we also find that evolutionary prescriptions in the optical i-(r ‑ i) CMDs predict, at fixed color, systematically lower luminosities than observed AGB stars.
Even in the absence of neutrino masses, a neutrino gas can exhibit a homogeneous flavor instability that leads to a periodic motion known as the fast flavor pendulum. A well-known necessary condition is a crossing of the angular flavor lepton distribution. In an earlier work, some of us showed that homogeneous flavor instabilities also obey a Nyquist criterion, inspired by plasma physics. This condition, while more restrictive than the angular crossing, is only sufficient if the unstable branch of the dispersion relation is bounded by critical points that both lie under the light cone (points with subluminal phase velocity). While the lepton-number angle distribution, assumed to be axially symmetric, easily allows one to determine the real-valued branch of the dispersion relation and to recognize if instead superluminal critical points exist, this graphical method does not translate into a simple instability condition. We discuss the homogeneous mode in the more general context of the dispersion relation for modes with arbitrary wave number and stress that it plays no special role on this continuum, except for its regular but fragile long-term behavior, owed to its many symmetries.
We measured the strange-meson spectrum in the scattering reaction $K^{-}+p \rightarrow K^{-}π^{-}π^{-}+p$ with the COMPASS spectrometer at CERN. Using the world's largest sample of this reaction, we performed a comprehensive partial-wave analysis of the mesonic final state. It substantially extends the strange-meson spectrum covering twelve states with masses up to 2.4 GeV/$c^2$. We observe the first candidate for a crypto-exotic strange meson with $J^{P}=0^{-}$ and find $K_3$ and $K_4$ states consistent with predictions for the ground states.
This paper presents a systematic study of X-ray-selected canonical tidal disruption events (TDEs) discovered in the western Galactic hemisphere of the first two eROSITA all-sky surveys (eRASS1 and eRASS2) performed between Dec 2019 and Dec 2020. We compiled a TDE sample from the catalog of eROSITA's extragalactic transients and variables eRO-ExTra, which includes X-ray sources with a variability significance and fractional amplitude over four between eRASS1 and eRASS2, not associated with known AGNs. Each X-ray source is associated with an optical counterpart from the Legacy Survey DR10. Canonical TDEs were selected based on their X-ray light-curve properties (single flare or decline), soft X-ray spectra ($Γ>3$), and the absence of archival X-ray variability and AGN signatures in their host photometry and spectroscopy. The sample includes 31 X-ray-selected TDE candidates with redshifts of $0.02< z<0.34$ and luminosities of $5.7 \times 10^{41}<L_X<5.3 \times 10^{44}$ erg/s in the 0.2-6.0 keV rest frame, of which 30 are canonical TDEs and one is an off-nuclear TDE candidate. The derived X-ray luminosity function is best fit by a double power law with a luminosity break at $10^{44}$ erg/s, corresponding to the Eddington-limiting prediction. This corresponds to a TDE volumetric rate of $ (2.3^{+1.2}_{-0.9})\times10^{-7}\,Mpc^{-3} yr^{-1}$ ($\approx1.2\times 10^{-5}$ events per galaxy per year). TDE host galaxies show a green-valley overdensity. In addition, 20%, 30%, and 15% of the sample exhibit flares in the optical, mid-infrared (mid-IR), or radio bands, respectively. We discuss the differences between X-ray, optical, and mid-IR TDE populations and the origins of multiwavelength flares in the context of the obscuring envelope and stream-stream collision models. Finally, we highlight TDE subpopulations that are not included in the canonical sample and should be explored in the future.
Dense neutrino gases can exhibit collective flavor instabilities, triggering large flavor conversions that are driven primarily by neutrino-neutrino refraction. One broadly distinguishes between fast instabilities that exist in the limit of vanishing neutrino masses, and slow ones, that require neutrino mass splittings. In a related series of papers, we have shown that fast instabilities result from the resonant growth of flavor waves, in the same way as turbulent electric fields in an unstable plasma. Here we extend this framework to slow instabilities, focusing on the simplest case of an infinitely homogeneous medium with axisymmetric neutrino distribution. The relevant length and time scales are defined by three parameters: the vacuum oscillation frequency ωE = δm2/2E, the scale of neutrino-neutrino refraction energy <inline-formula><mml:math><mml:mi>μ</mml:mi><mml:mo>=</mml:mo><mml:msqrt><mml:mn>2</mml:mn></mml:msqrt><mml:msub><mml:mi>G</mml:mi><mml:mi>F</mml:mi></mml:msub><mml:mfenced><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>ν</mml:mi></mml:msub><mml:mo>+</mml:mo><mml:msub><mml:mi>n</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:msub></mml:mrow></mml:mfenced></mml:math></inline-formula>, and the ratio between lepton and particle number <inline-formula><mml:math><mml:mi>ϵ</mml:mi><mml:mo>=</mml:mo><mml:mfenced><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>ν</mml:mi></mml:msub><mml:mo>‑</mml:mo><mml:msub><mml:mi>n</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:msub></mml:mrow></mml:mfenced><mml:mo>/</mml:mo><mml:mfenced><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>ν</mml:mi></mml:msub><mml:mo>+</mml:mo><mml:msub><mml:mi>n</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:msub></mml:mrow></mml:mfenced></mml:math></inline-formula>. We distinguish between two very different regimes: (i) For ωE ≪ μϵ2, instabilities occur at small spatial scales of order (μϵ)‑1 with a time scale of order <inline-formula><mml:math><mml:mi>ϵ</mml:mi><mml:msubsup><mml:mi>ω</mml:mi><mml:mi>E</mml:mi><mml:mrow><mml:mo>‑</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>. This novel branch of slow instability arises from resonant interactions with neutrinos moving along the axis of symmetry. (ii) For μϵ2 ≪ ωE ≪ μ, the instability is strongly non-resonant, with typical time and length scales of order <inline-formula><mml:math><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:msqrt><mml:mrow><mml:msub><mml:mi>ω</mml:mi><mml:mi>E</mml:mi></mml:msub><mml:mi>μ</mml:mi></mml:mrow></mml:msqrt></mml:math></inline-formula>. Unstable modes interact with all neutrino directions at once, recovering the characteristic scaling of the traditional studies of slow instabilities. In the inner regions of supernovae and neutron-star mergers, the first regime may be more likely to appear, meaning that slow instabilities in this region may have an entirely different character than usually envisaged.
Finding the best parametrization for cosmological models in the absence of first-principle theories is an open question. We propose a data-driven parametrization of cosmological models given by the disentangled "latent" representation of a variational autoencoder (VAE) trained to compress cosmic microwave background (CMB) temperature power spectra. We consider a broad range of <inline-formula><mml:math><mml:mrow><mml:mi>Λ</mml:mi></mml:mrow></mml:math></inline-formula>-cold-dark-matter (<inline-formula><mml:math><mml:mi>λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula>) and beyond-<inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> cosmologies with an additional early dark energy (EDE) component. We show that these spectra can be compressed into five (<inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula>) or eight (EDE) independent latent parameters, as expected when using temperature power spectra alone, and which reconstruct spectra at an accuracy well within the Planck errors. These latent parameters have a physical interpretation in terms of well-known features of the CMB temperature spectrum: these include the position, height and even-odd modulation of the acoustic peaks, as well as the gravitational lensing effect. The VAE also discovers one latent parameter which entirely isolates the EDE effects from those related to <inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> parameters, thus revealing a previously unknown degree of freedom in the CMB temperature power spectrum. We further showcase how to place constraints on the latent parameters using Planck data as typically done for cosmological parameters, obtaining latent values consistent with previous <inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> and EDE cosmological constraints. Our work demonstrates the potential of a data-driven reformulation of current beyond-<inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> phenomenological models into the independent degrees of freedom to which the data observables are sensitive.
In some scenarios for the early universe, non-relativistic thermal dark matter chemically decouples from the thermal environment once the temperature drops well below the dark matter mass. The value at which the energy density freezes out depends on the underlying model. In a simple setting, we provide a comprehensive study of heavy fermionic dark matter interacting with the light degrees of freedom of a dark thermal sector whose temperature T decreases from an initial value close to the freeze-out temperature. Different temperatures imply different hierarchies of energy scales. By exploiting the methods of non-relativistic effective field theories at finite T, we systematically determine the thermal and in-vacuum interaction rates. In particular, we address the impact of the Debye mass on the bound-state formation cross section and the bound-state dissociation and transition widths, and ultimately on the dark matter relic abundance. We numerically compare the corrections to the present energy density originating from the resummation of Debye mass effects with the corrections coming from a next-to-leading order treatment of the bath-particle interactions. We observe that the fixed-order calculation of the inelastic heavy-light scattering at high temperatures provides a larger dark matter depletion, and hence an undersized yield for given benchmark points in the parameter space, with respect to the calculation where Debye mass effects are resummed.
We extend the multireference covariant density functional theory (MR-CDFT) to describe the low-lying states of the odd-mass nucleus $^{43}$S near the neutron magic number $N=28$ with shape coexistence. The wave functions of the low-lying states are constructed as superpositions of configurations with different intrinsic shapes and $K$ quantum numbers, projected onto good particle numbers and angular momenta. The MR-CDFT successfully reproduces the main features of the low-energy structure in $^{43}$S. Our results indicate that the ground state, $3/2^-_1$, is predominantly composed of the intruder prolate one-quasiparticle (1qp) configuration $\nu1/2^-[321]$. In contrast, the $7/2^-_1$ state is identified as a high-$K$ isomer, primarily built on the prolate 1qp configuration $\nu7/2^-[303]$. Additionally, the $3/2^-_2$ state is found to be an admixture dominated by an oblate configuration with $K^π= 1/2^-$, along with a small contribution from a prolate configuration with $K^π= 3/2^-$. These results demonstrate the capability of MR-CDFT to capture the intricate interplay among shape coexistence, $K$-mixing, and isomerism in the low-energy structure of odd-mass nuclei around $N = 28$.
Historically, various methods have been employed to understand the origin of the elements, including observations of elemental abundances which have been compared to Galactic Chemical Evolution (GCE) models. It is also well known that 1D local thermodynamic equilibrium (LTE) measurements fail to accurately capture elemental abundances. Non-LTE (NLTE) effects may play a significant role, and neglecting them leads to erroneous implications in Galaxy modelling. In this paper, we calculate 3D NLTE abundances of seven key iron-peak and neutron-capture elements (Mn, Co, Ni, Sr, Y, Ba, and Eu) based on carefully assembled 1D LTE literature measurements, and investigate their impact within the context of the OMEGA+ GCE model. Our findings reveal that 3D NLTE abundances are significantly higher for iron-peak elements at [Fe/H] <inline-formula><tex-math id="TM0001" notation="LaTeX">$< -3$</tex-math></inline-formula>, with (for the first time ever) [Ni/Fe] and (confirming previous studies) [Co/Fe] on average reaching 0.6-0.8 dex, and [Mn/Fe] reaching <inline-formula><tex-math id="TM0002" notation="LaTeX">$-0.1$</tex-math></inline-formula> dex, which current 1D core-collapse supernova (CCSN) models cannot explain. We also observe a slightly higher production of neutron-capture elements at low metallicities, with 3D NLTE abundances of Eu being higher by + 0.2 dex at [Fe/H] <inline-formula><tex-math id="TM0003" notation="LaTeX">$= -3$</tex-math></inline-formula>. 3D effects are most significant for iron-peak elements in the very metal-poor regime, with average differences between 3D and 1D NLTE reaching up to 0.15 dex. Thus, ignoring 3D NLTE effects introduces significant biases, so including them should be considered whenever possible.
Aims. We study the individual and cumulative impact of stellar feedback processes on massive black hole (MBH) growth in a simulated low-mass dwarf galaxy. Methods. A suite of high-resolution radiation-hydrodynamic simulations called Noctua is performed, using the ArepoNoctua numerical framework for BHs in galaxy simulations. The chemical evolution of the gas is explicitly modelled in a time-dependent non-equilibrium way. Two types of stellar feedback are considered: individually-traced type II supernova (SNII) explosions, and radiatively transferred (on-the-fly) ionising stellar radiation (ISR) from OB stars. As part of the numerical framework, we develop and apply a novel physically-motivated model for MBH gas accretion, taking into account the angular momentum of the gas in the radiatively efficient regime, to estimate the gas accretion rate from the sub-grid accretion disc. Results. Without any stellar feedback, an initial $10^4~\mathrm{M}_\odot$ MBH is able to steadily grow over time, roughly doubling its mass after 800 Myr. Surprisingly, the growth of the MBH is more than doubled when only ISR feedback is considered, compared to the no stellar feedback run. This is due to the star formation rate (SFR) being highly suppressed (to a similar level or slightly above that when SNII feedback is considered), enabling a higher cumulative net gas inflow onto the MBH from not only the cold neutral- and molecular medium phases, but also the unstable- and warm neutral medium phases. With SNII feedback included, the gas accretion onto the MBH is episodic over time, and is suppressed by more than an order of magnitude already during the first 150 Myr. When combining SNII with ISR feedback, the growth of the MBH remains suppressed due to SNII feedback, but to a lesser extent compared to the SNII-only feedback run, due to a slightly lower SFR, and hence a reduced number of SNII events.
That neutrinos carry a nonvanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass holds relevance in fields from particle physics to cosmology. We report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium β-decay close to the kinematic endpoint. On the basis of the first five measurement campaigns, we derived a best-fit value of <inline-formula><mml:math><mml:mrow><mml:msubsup><mml:mi>m</mml:mi><mml:mi>ν</mml:mi><mml:mn>2</mml:mn></mml:msubsup><mml:mo>=</mml:mo><mml:mo>‑</mml:mo><mml:msubsup><mml:mrow><mml:mn>0.14</mml:mn></mml:mrow><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.15</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.13</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula> eV2, resulting in an upper limit of mν < 0.45 eV at 90% confidence level. Stemming from 36 million electrons collected in 259 measurement days, a substantial reduction of the background level, and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two.
Recent high-resolution observations indicate that the progenitors of globular clusters (GCs) at high redshifts had high average stellar surface densities above $10^5\, \mathrm{M}_\odot\, \mathrm{pc}^{-2}$. Studies of the internal structure and kinematics of the clusters, however, remain out of reach. Numerical simulations are necessary to decipher the origin of the zoo of spatio-kinematic features found in present-day GCs. Here we study star cluster formation in a star-by-star hydrodynamical simulation of a low-metallicity starburst occurring during a merger of two gas-rich dwarf galaxies. The simulation accounts for the multiphase interstellar medium, stellar radiation, winds and supernovae, and the accurate small-scale gravitational dynamics near massive stars. We also include prescriptions for stellar collisions and tidal disruption events by black holes. Gravitationally bound star clusters up to $\sim2\times10^5\, \mathrm{M}_\odot$ form dense with initial half-mass radii of $\sim0.1\unicode{x2013}1\, \mathrm{pc}$. The most massive cluster approaches the observed high-redshift surface densities throughout its hierarchical and dissipative assembly. The cluster also hosts a collisionally growing very massive star of $\sim1000\, \mathrm{M}_\odot$ that will eventually collapse, forming an intermediate mass black hole. The assembly leaves an imprint in the spatio-kinematic structure of the cluster. The younger half of stars is more centrally concentrated, rotates faster, and its velocity distribution is more radially biased at outer radii. The older population is more round in shape, rotates slowly, its velocity distribution is isotropic and its velocity dispersion is higher. These results provide a possible explanation for a subset of multiple population features observed in GCs such as NGC 104/47 Tuc.
Among the well-known methods to approximate derivatives of expectancies computed by Monte-Carlo simulations, averages of pathwise derivatives are often the easiest one to apply. Computing them via algorithmic differentiation typically does not require major manual analysis and rewriting of the code, even for very complex programs like simulations of particle-detector interactions in high-energy physics. However, the pathwise derivative estimator can be biased if there are discontinuities in the program, which may diminish its value for applications. This work integrates algorithmic differentiation into the electromagnetic shower simulation code HepEmShow based on G4HepEm, allowing us to study how well pathwise derivatives approximate derivatives of energy depositions in a sampling calorimeter with respect to parameters of the beam and geometry. We found that when multiple scattering is disabled in the simulation, means of pathwise derivatives converge quickly to their expected values, and these are close to the actual derivatives of the energy deposition. Additionally, we demonstrate the applicability of this novel gradient estimator for stochastic gradient-based optimization in a model example.
We calculate two-loop renormalization group equations (RGEs) in the Standard Model Effective Field Theory (SMEFT) with right-handed neutrinos, i.e., the so-called $ν$SMEFT, up to dimension five. Besides the two-loop RGEs of dimension-five (dim-5) operators, we also present those of the renormalizable couplings, including contributions from dim-5 operators. We check consistency relations among the first and second poles of $\varepsilon \equiv (4-d)/2$ with $d$ being the space-time dimension for all renormalization constants and find that those for lepton doublet and right-handed neutrino wave-function renormalization constants, as well as for renormalization constants of charged-lepton and neutrino Yukawa coupling matrices, do not hold. This leads to divergent RG functions for these fields and Yuwawa coupling matrices. We figure out that such infinite RG functions arise from the non-invariance of fields and Yukawa coupling matrices under field redefinitions, considering that flavor transformations are a kind of linear field redefinitions. Those infinite RG functions will disappear once one restores contributions from the derivative of renormalization constants with respect to the Wilson coefficients of redundant operators or, alternatively, considers the RGEs of flavor invariants, which are physical quantities and remain invariant under field redefinitions.
The R3B (Reactions with Relativistic Radioactive Beams) experiment as a major instrument of the NUSTAR collaboration for the research facility FAIR in Darmstadt is designed for kinematically complete studies of reactions with high-energy radioactive beams. Part of the broad physics program of R3B is to constrain the asymmetry term in the nuclear equation-of-state and hence improve the description of highly asymmetric nuclear matter (e.g., in neutron stars). For a precise determination of the neutron-skin thickness – an observable which is directly correlated with the symmetry energy in theoretical calculations – by measuring absolute fragmentation cross sections, it is essential to quantify the uncertainty and challenge the reaction model under stable conditions. During the successful FAIR Phase-0 campaign of R3B, we precisely measured the energy dependence of total interaction cross sections in 12C+12C collisions, for a direct comparison with calculations based on the eikonal reaction theory.
The synthesis of life from non-living matter has captivated and divided scientists for centuries. This bold goal aims at unraveling the fundamental principles of life and leveraging its unique features, such as its resilience, sustainability, and ability to evolve. Synthetic life represents more than an academic milestone—it has the potential to revolutionize biotechnology, medicine, and materials science. Although the fields of synthetic biology, systems chemistry, and biophysics have made great strides toward synthetic life, progress has been hindered by social, philosophical, and technical challenges, such as vague goals, misaligned interdisciplinary efforts, and incompletely addressing public and ethical concerns. Our perspective offers a roadmap toward the synthesis of life based on discussions during a 2-week workshop with scientists from around the globe.
We present a formulation of coherent states as of consistent quantum description of classical configurations in the Becchi-Rouet-Stora-Tyutin (BRST)-invariant quantization of electrodynamics. The quantization with proper gauge-fixing is performed on the vacuum of the theory, whereas other backgrounds are obtained as BRST-invariant coherent states. One of the key insights is the possibility of constructing the coherent states of pure-gauge configurations. This provides a coherent state understanding of topologically nontrivial configurations in gauge theories and makes a number of features, such as the suppression of transitions between topologically distinct sectors, very transparent at full quantum level. As an example, we construct the Nielsen-Olesen string as a BRST-invariant coherent state. The Abelian pure-gauge configurations can also be viewed as useful analogs for a set of space-times related by coordinate reparametrizations in general relativity.
Historically, various methods have been employed to understand the origin of the elements, including observations of elemental abundances which have been compared to Galactic Chemical Evolution (GCE) models. It is also well known that 1D Local Thermodynamic Equilibrium (LTE) measurements fail to accurately capture elemental abundances. Non-LTE (NLTE) effects may play a significant role, and neglecting them leads to erroneous implications in galaxy modelling. In this paper, we calculate 3D NLTE abundances of seven key iron-peak and neutron-capture elements (Mn, Co, Ni, Sr, Y, Ba, Eu) based on carefully assembled 1D LTE literature measurements, and investigate their impact within the context of the OMEGA+ GCE model. Our findings reveal that 3D NLTE abundances are significantly higher for iron-peak elements at [Fe/H] <-3, with (for the first time ever) [Ni/Fe] and (confirming previous studies) [Co/Fe] on average reaching 0.6-0.8 dex, and [Mn/Fe] reaching -0.1 dex, which current 1D core-collapse supernova (CCSN) models cannot explain. We also observe a slightly higher production of neutron-capture elements at low metallicities, with 3D NLTE abundances of Eu being higher by +0.2 dex at [Fe/H] =-3. 3D effects are most significant for iron-peak elements in the very metal-poor regime, with average differences between 3D NLTE and 1D NLTE reaching up to 0.15 dex. Thus, ignoring 3D NLTE effects introduces significant biases, so including them should be considered whenever possible.
We introduce a novel orbit superposition method designed to reconstruct the stellar density structure, kinematics, and chemical abundance distribution of the entire Milky Way by leveraging 6D phase-space information from its resolved stellar populations, limited by the spatial coverage of APOGEE DR17.
Central regions of nearby disc galaxies display a large variety of structures in their stellar and gas disc that illustrates the outcome of a complex and dynamic evolution. The most visible central structure inside the bar region is the inner molecular disc (the so-called Central Molecular Zone (CMZ) in the Milky Way). Recent observational campaigns have shown that those inner molecular discs have a typical size ranging from a few hundred parsecs to one kiloparsec and tend to appear at the centre of barred discs. The physical phenomena involved in the building, consumption (e.g., star formation) and long-term evolution of those inner gas structures are still strongly debated. It is commonly accepted that the bar plays a role in the fuelling of gas from the large few kiloparsec scale to the inner molecular disc region. However, the exact physical processes involved in the loss of gas angular momentum (e.g., gravitational torques, shear, feedback) and its transport to the centre are not fully understood. Moreover, inner gas discs are intermediate-scale structures which connect the large kiloparsec scale and the subparsec scale physics (e.g., stellar-driven feedback, magnetic torques) involved in the fuelling of the central supermassive black hole (SMBH). Therefore, those inner discs can be considered as ‘gas reservoirs’ and may be efficient suppliers of material for the flickering of the central black hole, the so-called Active Galactic Nuclei (AGN). [...]
This study presents a novel method using spin quantum sensors to explore temporal variations of fundamental constants, significantly expanding the frequency range and providing constraints on scalar dark matter.
In dense neutrino environments like core-collapse supernovae (CCSNe) and neutron star mergers, neutrinos can undergo fast flavor conversions when their angular distribution of neutrino electron lepton number (<inline-formula><mml:math><mml:mi>ν</mml:mi><mml:mi>ELN</mml:mi></mml:math></inline-formula>) crosses zero along some directions. While previous studies have demonstrated the detection of axisymmetric <inline-formula><mml:math><mml:mi>ν</mml:mi><mml:mi>ELN</mml:mi></mml:math></inline-formula> crossings in these extreme environments, nonaxisymmetric crossings have remained elusive, mostly due to the absence of models for their angular distributions. In this study, we present a pioneering analysis of the detection of nonaxisymmetric <inline-formula><mml:math><mml:mi>ν</mml:mi><mml:mi>ELN</mml:mi></mml:math></inline-formula> crossings using machine learning (ML) techniques. Our ML models are trained on data from two CCSN simulations, one with rotation and one without, where nonaxisymmetric features in neutrino angular distributions play a crucial role. We demonstrate that our ML models achieve detection accuracies exceeding 90%. This is an important improvement, especially considering that a significant portion of <inline-formula><mml:math><mml:mi>ν</mml:mi><mml:mi>ELN</mml:mi></mml:math></inline-formula> crossings in these models eluded detection by earlier methods.
We compute the photon self-energy to three loops in Quantum Electrodynamics. The method of differential equations for Feynman integrals and a complete ϵ-factorization of the former allow us to obtain fully analytical results in terms of iterated integrals involving integration kernels related to a K3 geometry. We argue that our basis has the right properties to be a natural generalization of a canonical basis beyond the polylogarithmic case and we show that many of the kernels appearing in the differential equations, cancel out in the final result to finite order in ϵ. We further provide generalized series expansions that cover the whole kinematic space so that our results for the self-energy may be easily evaluated numerically for all values of the momentum squared. From the local solution at p2 = 0, we extract the photon wave function renormalization constant in the on-shell scheme to three loops and confirm its agreement with previously obtained results.
We study the deflection of light rays in a cold, nonmagnetized plasma using the worldline framework. Starting from Synge's Hamiltonian formalism, we construct a position-space action and use it perturbatively to calculate light bending angles. In the homogeneous case, the action reduces to that of a massive particle, allowing us to extract the bending angle of light in the presence of the medium using a well-known analogy. For the inhomogeneous case, we consider a power law model and construct Feynman rules in time to compute the purely plasma-induced corrections to the bending angle at next-to-leading-order.
Perturbative calculations for processes involving heavy flavours can be carried out using two approaches: the massive and the massless schemes. These schemes can also be combined to leverage their respective strengths. Additionally, both massive and massless frameworks can be supplemented by soft-gluon resummation. However, matching resummed calculations across the two schemes presents significant challenges, primarily due to the non-commutativity of the soft and small mass limits. The consistent resummation of mass and soft logarithms has been recently achieved at next-to-leading logarithmic (NLL) accuracy. In this paper, we consider heavy-quark fragmentation functions in electron-positron collisions and we extend this framework to achieve the so-called NLL<inline-formula><mml:math><mml:mmultiscripts><mml:mrow></mml:mrow><mml:mrow></mml:mrow><mml:mo>'</mml:mo></mml:mmultiscripts></mml:math></inline-formula> accuracy, which accounts for finite terms in the soft limit.
Ultra-hot Jupiters, an extreme class of planets not found in our Solar System, provide a unique window into atmospheric processes. The extreme temperature contrasts between their day and night sides pose a fundamental climate puzzle: how is energy distributed? To address this, we must observe the three-dimensional structure of these atmospheres, particularly their vertical circulation patterns that can serve as a testbed for advanced global circulation models, for example, in ref. 1. Here we show a notable shift in atmospheric circulation in an ultra-hot Jupiter: a unilateral flow from the hot star-facing side to the cooler space-facing side of the planet sits below an equatorial super-rotational jet stream. By resolving the vertical structure of atmospheric dynamics, we move beyond integrated global snapshots of the atmosphere, enabling more accurate identification of flow patterns and allowing for a more nuanced comparison to models. Global circulation models based on first principles struggle to replicate the observed circulation pattern2 underscoring a critical gap between theoretical understanding of atmospheric flows and observational evidence. This work serves as a testbed to develop more comprehensive models applicable beyond our Solar System as we prepare for the next generation of giant telescopes.
We summarize the status of the kaon theory 50 years after the seminal paper of Kobayashi and Maskawa [Prog. Theor. Phys. 49, 652 (1973)], who pointed out that six quarks are necessary to have CP violation in the Standard Model (SM) and presented a parametrization of a 3 × 3 unitary matrix that, after the discovery of the charm quark in 1974 and the b quark in 1977, dominated the field of flavor-changing processes. One of the main goals of flavor physics since then has been the determination of the four parameters of this matrix, which we will choose here to be |Vus|, |Vcb|, and the two angles of the unitarity triangle, β and γ, with |Vus| introduced by Cabibbo in 1963. I will summarize the recent strategy for determination of these parameters without new physics (NP) infection. It is based on the conjecture of the absence of relevant NP contributions to ΔF = 2 processes that indeed can be demonstrated by a negative rapid test: the |Vcb|-γ plot. This in turn allows one to obtain SM predictions for rare K and B decays that are the most precise to date. We present strategies for the explanation of the anticipated anomaly in the ratio ɛ'/ɛ and the observed anomalies in b → sμ+μ- transitions that are consistent with our ΔF = 2 conjecture. In particular, the absence of NP in the parameter ɛK still allows for significant NP effects in ɛ'/ɛ and in rare kaon decays, moreover, in a correlated manner. Similarly, the absence of NP in ΔMs combined with anomalies in b → sμ+μ- transitions hints at the presence of right-handed quark currents. We also discuss how the nature of neutrinos, Dirac vs. Majorana ones, can be probed in <inline-formula><tex-math id="TM0001" notation="LaTeX">$K\rightarrow \pi \nu \bar{\nu }$</tex-math></inline-formula> and <inline-formula><tex-math id="TM0002" notation="LaTeX">$B\rightarrow K(K^{*})\nu \bar{\nu }$</tex-math></inline-formula> decays. The present status of the ΔI = 1/2 rule and ɛ'/ɛ is summarized.
We construct the equation of state of hypernuclear matter and study the structure of neutron stars employing a chiral hyperon-nucleon interaction of the Jülich–Bonn group tuned to femtoscopic <inline-formula><mml:math><mml:mrow><mml:mi>Λ</mml:mi><mml:mi>p</mml:mi></mml:mrow></mml:math></inline-formula> data of the ALICE Collaboration, and <inline-formula><mml:math><mml:mrow><mml:mi>Λ</mml:mi><mml:mi>Λ</mml:mi></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi>Ξ</mml:mi></mml:math></inline-formula>N interactions determined from lattice QCD calculations by the HAL QCD Collaboration that reproduce the femtoscopic <inline-formula><mml:math><mml:mrow><mml:mi>Λ</mml:mi><mml:mi>Λ</mml:mi></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi>Ξ</mml:mi><mml:mo>-</mml:mo></mml:msup><mml:mi>p</mml:mi></mml:mrow></mml:math></inline-formula> data. We employ the ab-initio microscopic Brueckner–Hartree–Fock theory extended to the strange baryon sector. A special focus is put on the uncertainties of the hyperon interactions and how they are effectively propagated to the composition, equation of state, mass-radius relation and tidal deformability of neutron stars. To such end, we consider the uncertainty due to the experimental error of the femtoscopic <inline-formula><mml:math><mml:mrow><mml:mi>Λ</mml:mi><mml:mi>p</mml:mi></mml:mrow></mml:math></inline-formula> data used to fix the chiral hyperon-nucleon interaction and the theoretical uncertainty, estimated from the residual cut-off dependence of this interaction. We find that the final maximum mass of a neutron star with hyperons is in the range 1.3–1.4 <inline-formula><mml:math><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula>, in agreement with previous works. The hyperon puzzle, therefore, remains still an open issue if only two-body hyperon-nucleon and hyperon-hyperon interactions are considered. Predictions for the tidal deformability of neutron stars with hyperons are found to be in agreement with the observational constraints from the gravitational wave event GW170817 in the mass range 1.1–1.3 <inline-formula><mml:math><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula>.
This thesis investigates an interacting dark sector, where dark matter scatters off relativistic dark radiation, analogous to photon-electron interaction. This scenario has the potential to address cosmological tensions. Key results include constraints from full-shape galaxy clustering data, cluster abundance analyses, and forecasts for future galaxy cluster surveys. The thesis also refines the computation of the interaction rate, addressing the divergences and incorporating corrections.
In many quantitative investigations of biological systems, including, e.g., the study of biomolecular interactions, assembly and disassembly, aggregation, micelle and vesicle formation, or drug encapsulation, accurate determination of particle sizes is of key interest. Fluorescence correlation spectroscopy (FCS), with its exceptional sensitivity for molecular diffusion properties, has long been proposed as a valuable method to size small, freely diffusible particles with superior precision. It is conceptually related to the more widespread particle sizing technique dynamic light scattering (DLS) but offers greater selectivity and sensitivity due to the use of fluorescence rather than scattered light. However, in spite of these apparent advantages, FCS has never become established as a biophysical routine for particle sizing. This is due to the fact that sensitivity can, under certain conditions, indeed be disadvantageous, as it renders the technique error prone and overly susceptible to signal disturbances. Here, we discuss the systematic challenges, as well as the advances made over the past decades, to employing FCS in polydisperse samples. The problematic role of large particles, a common issue in DLS and FCS, and the effect of fluorescent labeling are discussed in detail, along with strategies for respective error mitigation in experiments and data analysis. We expect this overview to guide future users in successfully applying FCS to their particle sizing problems in the hope of fostering a more widespread and routine use of FCS-based technology.
Bacterial cell division relies on the Z ring, a cytoskeletal structure that acts as a scaffold for the assembly of the divisome. To date, the detailed mechanisms underlying the assembly and stabilization of the Z ring remain elusive. This study highlights the role of the FtsZ-associated protein (Zap) ZapD in the assembly and stabilization of Z-ring-like structures via filament crosslinking. Using cryo-electron tomography and biochemical analysis, we show that, at equimolar concentrations of ZapD and FtsZ, ZapD induces the formation of toroidal structures composed of short, curved FtsZ filaments that are crosslinked vertically, but also laterally and diagonally. At higher concentrations of ZapD, regularly spaced ZapD dimers crosslink FtsZ filaments from above, resulting in the formation of straight bundles. Despite the simplicity of this reconstituted system, these findings provide valuable insights into the structural organization and stabilization of the Z ring by Zap proteins in bacterial cells, revealing the key role of optimal crosslinking density and geometry in enabling filament curvature and ring formation.
We study stellar core growth in simulations of merging massive (<inline-formula><tex-math id="TM0001" notation="LaTeX">$M_\star \gt 10^{11}\, \mathrm{M}_{\odot }$</tex-math></inline-formula>) elliptical galaxies by a supermassive black hole (SMBH) displaced by gravitational wave induced recoil velocity. With controlled, dense sampling of the SMBH recoil velocity, we find the core radius originally formed by SMBH binary scouring can grow by a factor of 2-3 when the recoil velocity exceeds <inline-formula><tex-math id="TM0002" notation="LaTeX">$\sim 50$</tex-math></inline-formula> per cent of the central escape velocity, and the mass deficit grows by up to a factor of <inline-formula><tex-math id="TM0003" notation="LaTeX">$\sim 4$</tex-math></inline-formula>. Using Bayesian inference we predict the distribution of stellar core sizes formed through this process to peak at <inline-formula><tex-math id="TM0004" notation="LaTeX">$\sim 1\, \mathrm{kpc}$</tex-math></inline-formula>. An orbital decomposition of stellar particles within the core reveals that radial orbits dominate over tube orbits when the recoil velocity exceeds the velocity dispersion of the core, whereas tube orbits dominate for the lowest recoil kicks. A change in orbital structure is reflected in the anisotropy parameter, with a central tangential bias present only for recoil velocities less than the local stellar velocity dispersion. Emulating current integral field unit observations of the stellar line-of-sight velocity distribution, we uncover a distinct signature in the Gauss-Hermite symmetric deviation coefficient <inline-formula><tex-math id="TM0005" notation="LaTeX">$h_4$</tex-math></inline-formula> that uniquely constrains the core size due to binary scouring. This signature is insensitive to the later evolution of the stellar mass distribution due to SMBH recoil. Our results provide a novel method to estimate the SMBH recoil magnitude from observations of local elliptical galaxies, and implies these galaxies primarily experienced recoil velocities less than the stellar velocity dispersion of the core.
This study presents a novel method using spin quantum sensors to explore temporal variations of fundamental constants, significantly expanding the frequency range and providing constraints on scalar dark matter.
Understanding the ages of stars is crucial for unraveling the formation history and evolution of our Galaxy. Traditional methods for estimating stellar ages from spectroscopic data often struggle with providing appropriate uncertainty estimations and are severely constrained by the parameter space. In this work, we introduce a new approach using normalizing flows, a type of deep generative model, to estimate stellar ages for evolved stars with improved accuracy and robust uncertainty characterization. The model is trained on stellar masses for evolved stars derived from asteroseismology and predicts the relationship between the carbon and nitrogen abundances of a given star and its age. Unlike standard neural network techniques, normalizing flows enable the recovery of full likelihood distributions for individual stellar ages, offering a richer and more informative perspective on uncertainties. Our method yields age estimations for 378,720 evolved stars and achieves a typical absolute age uncertainty of approximately 2 Gyr. By intrinsically accounting for the coverage and density of the training data, our model ensures that the resulting uncertainties reflect both the inherent noise in the data and the completeness of the sampled parameter space. Applying this method to data from the SDSS-V Milky Way Mapper, we have produced the largest stellar age catalog for evolved stars to date.
We have carried out a systematic search for galaxy-scale lenses exploiting multi-band imaging data from the third public data release of the Hyper Suprime-Cam (HSC) survey with the focus on false-positive removal, after applying deep learning classifiers to all 110 million sources with i-Kron radius above 0.8". To improve the performance, we tested the combination of multiple networks from our previous lens search projects and found the best performance by averaging the scores from five of our networks. Although this ensemble network leads already to a false-positive rate (FPR) of 0.01% at a true-positive rate (TPR) of 75% on known real lenses, we have elaborated techniques to further clean the network candidate list before visual inspection. In detail, we tested the rejection using SExtractor and the modeling network from HOLISMOKES IX, which resulted together in a candidate rejection of 29% without lowering the TPR. We carried out a comprehensive multi-stage visual inspection involving eight individuals and identified 95 grade A (average grade G >2.5) and 503 grade B (2.5 >G >1.5) lens candidates, including 92 discoveries reported for the first time. This inspection also incorporated a novel environmental characterization using histograms of photometric redshifts. We publicly release the average grades, mass model predictions, and environment characterization of all visually inspected candidates, while including references for previously discovered systems, which makes this catalog one of the largest compilation of known lenses. The results demonstrate that (1) the combination of multiple networks enhances the selection performance and (2) both automated masking tools as well as modeling networks, which can be easily applied to hundreds of thousands of network candidates, help reduce the number of false positives that is the main limitation in lens search to date.
Context. Theoretical models of structure formation predict the presence of a hot gaseous atmosphere around galaxies. While this hot circumgalactic medium (CGM) has been observationally confirmed through UV absorption lines, the detection of its direct X-ray emission remains scarce. Recent results from the eROSITA collaboration have claimed the detection of the CGM out to the virial radius for a stacked sample of Milky Way-mass galaxies. Aims. We investigate theoretical predictions of the intrinsic CGM X-ray surface brightness (SB) using simulated galaxies and connect them to their global properties, such as the gas temperature, hot gas fraction, and stellar mass. Methods. We selected a sample of central galaxies from the ultra-high-resolution cosmological volume (48 cMpc h‑1) of the Magneticum Pathfinder set of hydrodynamical cosmological simulations. We classified them as star-forming (SF) or quiescent (QU) based on their specific star formation rate (SFR). For each galaxy, we generated X-ray mock data using the X-ray photon simulator PHOX, from which we obtained SB profiles out to the virial radius for different X-ray emitting components; namely, gas, active galactic nuclei (AGNs), and X-ray binaries (XRBs). We fit a β-profile to the gas component of each galaxy and observed trends between its slope and global quantities of the simulated galaxy. Results. We found marginal differences among the average total SB profile in SF and QU galaxies beyond r > 0.05 Rvir. The relative contribution from hot gas exceeds 70% and is non-zero (≲10%) for XRBs in both galaxy types. At small radii (r < 0.05 Rvir), XRBs dominate the SB profile over the hot gas for QU galaxies. We found positive correlations between the galaxies' global properties and the normalization of their SB profiles. The fitted β-profile slope is correlated with the total gas luminosity, which, in turn, shows strong connections to the current accretion rate of the central supermassive black hole (SMBH). We found the halo scaling relations to be consistent with the literature.
We introduce an extension of the evolution mapping framework to cosmological models that include massive neutrinos. The original evolution mapping framework exploits a degeneracy in the linear matter power spectrum when expressed in ${\rm Mpc}$ units, which compresses its dependence on cosmological parameters into those that affect its shape and a single extra parameter $\sigma_{12}$, defined as the RMS linear variance in spheres of radius $12 {\rm Mpc}$. We show that by promoting the scalar amplitude of fluctuations, $A_{\rm s}$, to a shape parameter, we can additionally describe the suppression due to massive neutrinos at any redshift to sub-0.01\% accuracy across a wide range of masses and for different numbers of mass eigenstates. This methodology has been integrated into the public COMET package, enhancing its ability to emulate predictions of state-of-the-art perturbative models for galaxy clustering, such as the effective field theory (EFT) model. Additionally, the updated software now accommodates a broader cosmological parameter space for the emulator, enables the simultaneous generation of multiple predictions to reduce computation time, and incorporates analytic marginalisation over nuisance parameters to expedite posterior estimation. Finally, we explore the impact of different infrared resummation techniques on galaxy power spectrum multipoles, demonstrating that any discrepancies can be mitigated by EFT counterterms without impacting the cosmological parameters.
Solid-state phonon and charge detectors probe the scattering of weakly interacting particles, such as dark matter and neutrinos, through their low recoil thresholds. Recent advancements have pushed sensitivity to eV-scale energy depositions, uncovering previously-unseen low-energy excess backgrounds. While some arise from known processes such as thermal radiation, luminescence, and stress, others remain unexplained. This review examines these backgrounds, their possible origins, and parallels to low-energy effects in solids. Their understanding is essential for interpreting particle interactions at and below the eV-scale.
Dark matter (DM) environments around black holes (BHs) can influence their mergers through dynamical friction, causing gravitational wave (GW) dephasing during the inspiral phase. While this effect is well studied for collisionless dark matter (CDM), it remains unexplored for self-interacting dark matter (SIDM) due to the typically low DM density in SIDM halo cores. In this work, we show that SIDM models with a massive force mediator can support dense enough DM spikes, significantly affecting BH mergers and producing a distinct GW dephasing. Using ${N}$-body simulations, we analyze GW dephasing in binary BH inspirals within CDM and SIDM spikes. By tracking the binary's motion in different SIDM environments, we show that the Laser Interferometer Space Antenna (LISA) can distinguish DM profiles shaped by varying DM interaction strengths, revealing detailed properties of SIDM.
We demonstrate that chiral symmetry breaking occurs in the confining regime of QCD-like theories with <mml:math altimg="si1.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:math> colors and <mml:math altimg="si2.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:msub></mml:math> flavors. Our proof is based on a novel strategy, called 'downlifting', by which solutions of the 't Hooft anomaly matching and persistent mass conditions for a theory with <mml:math altimg="si3.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:msub><mml:mo linebreak="goodbreak" linebreakstyle="after">‑</mml:mo><mml:mn>1</mml:mn></mml:math> flavors are constructed from those of a theory with <mml:math altimg="si2.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:msub></mml:math> flavors, while <mml:math altimg="si1.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:math> is fixed. By induction, chiral symmetry breaking is proven for any <mml:math altimg="si22.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:msub><mml:mo>≥</mml:mo><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi><mml:mi>i</mml:mi><mml:mi>n</mml:mi></mml:mrow></mml:msub></mml:math> in the confining regime, where <mml:math altimg="si5.svg"><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi><mml:mi>i</mml:mi><mml:mi>n</mml:mi></mml:mrow></mml:msub></mml:math> is the smallest prime factor of <mml:math altimg="si1.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:math>. The proof can be extended to <mml:math altimg="si6.svg"><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>f</mml:mi></mml:mrow></mml:msub><mml:mo linebreak="goodbreak" linebreakstyle="after"><</mml:mo><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi><mml:mi>i</mml:mi><mml:mi>n</mml:mi></mml:mrow></mml:msub></mml:math> under the additional assumption on the absence of phase transitions when quark masses are sent to infinity. Our results do not rely on assumptions on the spectrum of massless bound states other than the fact that they are color-singlet hadrons.
We investigate the energy release in the interacting magnetospheres of binary neutron stars (BNSs) with global 3D force-free electrodynamics simulations. The system dynamics depend on the inclinations χ1 and χ2 of the stars' magnetic dipole moments relative to their orbital angular momentum. The simplest aligned configuration (χ1 = χ2 = 0∘) has no magnetic field lines connecting the two stars. Remarkably, it still develops separatrix current sheets warping around each star and a dissipative region at the interface of the two magnetospheres. A Kelvin–Helmholtz (KH)–type instability drives significant dissipation at the magnetospheric interface, generating local Alfvénic turbulence and escaping fast magnetosonic waves. Binaries with inclined magnetospheres release energy in two ways: via KH instability at the interface and via magnetic reconnection flares in the twisted flux bundles connecting the companions. Outgoing compressive waves occur in a broad range of BNS parameters, possibly developing shocks and sourcing fast radio bursts. We discuss implications for X-ray and radio precursors of BNS mergers.
Robust modeling of non-linear scales is critical for accurate cosmological inference in Stage IV surveys. For weak lensing analyses in particular, a key challenge arises from the incomplete understanding of how non-gravitational processes, such as supernovae and active galactic nuclei — collectively known as baryonic feedback — affect the matter distribution. Several existing methods for modeling baryonic feedback treat it independently from the underlying cosmology, an assumption which has been found to be inaccurate by hydrodynamical simulations. In this work, we examine the impact of this coupling between baryonic feedback and cosmology on parameter inference at LSST Y1 precision. We build mock 3×2pt data vectors using the Magneticum suite of hydrodynamical simulations, which span a wide range of cosmologies while keeping subgrid parameters fixed. We perform simulated likelihood analyses for two baryon mitigation techniques: (i) the Principal Component Analysis (PCA) method which identifies eigenmodes for capturing the effect baryonic feedback on the data vector and (ii) HMCODE2020 [1] which analytically models the modification in the matter distribution using a halo model approach. Our results show that the PCA method is more robust than HMCODE2020 with biases in Ωm-S 8 up to 0.3σ and 0.6σ, respectively, for large deviations from the baseline cosmology. For HMCODE2020, the bias correlates with the input cosmology while for PCA we find no such correlation.
Cyanopolyynes are among the largest and most commonly observed interstellar complex organic molecules in star-forming regions. They are believed to form primarily in the gas phase, but their formation routes are not well understood. We present a comprehensive study of the gas-phase formation network of cyanobutadiyne, HC<inline-formula><tex-math id="TM0001" notation="LaTeX">$_5$</tex-math></inline-formula>N, based on new theoretical calculations, kinetics experiments, astronomical observations, and astrochemical modelling. We performed new quantum mechanics calculations for six neutral-neutral reactions in order to derive reliable rate coefficients and product branching fractions. We also present new CRESU data on the rate coefficients of three of these reactions (C<inline-formula><tex-math id="TM0002" notation="LaTeX">$_3$</tex-math></inline-formula>N + C<inline-formula><tex-math id="TM0003" notation="LaTeX">$_2$</tex-math></inline-formula>H<inline-formula><tex-math id="TM0004" notation="LaTeX">$_2$</tex-math></inline-formula>, C<inline-formula><tex-math id="TM0005" notation="LaTeX">$_2$</tex-math></inline-formula>H + HC<inline-formula><tex-math id="TM0006" notation="LaTeX">$_3$</tex-math></inline-formula>N, CN + C<inline-formula><tex-math id="TM0007" notation="LaTeX">$_4$</tex-math></inline-formula>H<inline-formula><tex-math id="TM0008" notation="LaTeX">$_2$</tex-math></inline-formula>) obtained at temperatures as low as 24 K. In practice, six out of nine reactions currently used in astrochemical models have been updated in our reviewed network. We also report the tentative detection of the <inline-formula><tex-math id="TM0009" notation="LaTeX">$^{13}$</tex-math></inline-formula>C isotopologues of HC<inline-formula><tex-math id="TM0010" notation="LaTeX">$_5$</tex-math></inline-formula>N in the L1544 prestellar core. We derived a lower limit of <inline-formula><tex-math id="TM0011" notation="LaTeX">$^{12}$</tex-math></inline-formula>C/<inline-formula><tex-math id="TM0012" notation="LaTeX">$^{13}$</tex-math></inline-formula>C > 75 for the HC<inline-formula><tex-math id="TM0013" notation="LaTeX">$_5$</tex-math></inline-formula>N isotopologues, which does not allow to bring new constraints to the HC<inline-formula><tex-math id="TM0014" notation="LaTeX">$_5$</tex-math></inline-formula>N chemistry. Finally, we verified the impact of the revised reactions by running the GRETOBAPE astrochemical model. We found good agreement between the HC<inline-formula><tex-math id="TM0015" notation="LaTeX">$_5$</tex-math></inline-formula>N predicted and observed abundances in cold (<inline-formula><tex-math id="TM0016" notation="LaTeX">$\sim$</tex-math></inline-formula>10 K) objects, demonstrating that HC<inline-formula><tex-math id="TM0017" notation="LaTeX">$_5$</tex-math></inline-formula>N is mainly formed by neutral-neutral reactions in these environments. In warm molecular shocks, instead, the predicted abundances are a factor of ten lower with respect to observed ones. In this environment possessing an higher gas ionization fraction, we speculate that the contribution of ion-neutral reactions could be significant.
A possible way of constructing polylogarithms on Riemann surfaces of higher genera facilitates integration kernels, which can be derived from generating functions incorporating the geometry of the surface. Functional relations among polylogarithms rely on identities for those integration kernels. In this article, we derive identities for Enriquez' meromorphic generating function and investigate the implications for the associated integration kernels. The resulting identities are shown to be exhaustive and therefore reproduce all identities for Enriquez' kernels conjectured in arXiv:2407.11476 recently.
The inner Solar System is depleted in refractory carbon in comparison to the interstellar medium and the depletion likely took place in the protoplanetary disk phase of the Solar System. We study the effect of photolysis of refractory carbon in the upper layers of the protosolar disk and its interplay with dust collisional growth and vertical mixing. We make use of a 1D Monte Carlo model to simulate dust coagulation and vertical mixing. To model the FUV flux of the disk, we use a simple analytical prescription and benchmark it with data from a radiative transfer simulation. We study the effects of fragmentation and bouncing on dust distribution and the propagation of carbon depletion. We find that when bouncing is included, the size distribution is truncated at smaller sizes than fragmentation-limited size distributions but there is a loss of small grains as well. The population of small grains is reduced due to fewer fragmentation events and this reduces the effectiveness of photolysis. We find that dust collisional growth and vertical mixing increase the effectiveness of carbon depletion by efficiently replenishing carbon to the upper regions of the disk with higher FUV flux. It takes around 100-300 kyr to reach the measured carbon abundances at 1 au, depending on the strength of the turbulence in the disk. These timescales are faster than reported by previous studies. Collisional redistribution and turbulent mixing are important aspects of dust evolution that should be included when modeling dust chemistry as they can influence the efficiency of chemical processes. Photolysis, along with another process such as sublimation, most likely played a key role in refractory carbon depletion that we see around us in the inner Solar System.
We present a systematic study of one-loop quantum corrections in scalar effective field theories from a geometric viewpoint, emphasizing the role of field-space curvature and its renormalisation. By treating the scalar fields as coordinates on a Riemannian manifold, we exploit field redefinition invariance to maintain manifest coordinate independence of physical observables. Focusing on the non-linear sigma model (NLSM) and \(\phi^4\) theory, we demonstrate how loop corrections induce momentum- and scale-dependent shifts in the curvature of the field-space manifold. These corrections can be elegantly captured through the recently proposed geometry-kinematics duality, which generalizes the colour-kinematics duality in gauge theories to curved field-space backgrounds. Our results highlight a universal structure emerging in the contractions of Riemann tensors that contribute to renormalisation of the field-space curvature. In particular, we find explicit expressions and a universal structure for the running curvature and Ricci scalar in simple models, illustrating how quantum effects reshape the underlying geometry. This geometric formulation unifies a broad class of scalar EFTs, providing insight into the interplay of curvature, scattering amplitudes, and renormalisation.
This paper presents a quantitative analysis of the stellar content in the Local Group dwarf irregular galaxy NGC 6822 by comparing stellar evolution models and observations in color-magnitude diagrams (CMDs) and color-color diagrams (CC-Ds). Our analysis is based on optical ground-based g,r,i photometry, and deep archive HST photometry of two fields in the galaxy disk. We compared young, intermediate-age, and old stellar populations with isochrones from the BaSTI-IAC library and found that NGC 6822 hosts a quite metal-rich ([Fe/H] = -0.7 to -0.4) young component with an age ranging from 20 to 100 Myr. The intermediate-age population experienced a modest chemical enrichment between 4 and 8 Gyr ago while stars older than 11 Gyr have a low metal abundance ([Fe/H] ~ -1.70). We also identified the AGB clump population with a luminosity peak at i ~ 23.35 mag. Our analysis of both the CMD and the optical-NIR-MIR CC-Ds of AGB oxygen- and carbon-rich stars, using the PARSEC+COLIBRI isochrones with and without circumstellar dust, reveal that this stellar component exhibits a spread in age from 1 to 2 Gyr and in metallicity between [Fe/H]=-1.30 and -1.70. The stellar models we used reproduce very well the two distinct color sequences defined by AGB O- and C-rich stars in the various optical-NIR-MIR CC-Ds, suggesting that they are reliable diagnostics to identify and characterise intermediate-age stellar populations. However, we also find that evolutionary prescriptions in the optical i-(r-i) CMDs predict, at fixed color, systematically lower luminosities than observed AGB stars.
Star clusters can interact and merge in galactic discs, halos, or centers. We present direct N-body simulations of binary mergers of star clusters with M⋆ = 2.7 × 104 M⊙ each, using the N-body code BIFROSTwith subsystem regularisation and post-Newtonian dynamics. We include 500 M⊙ massive black holes (MBHs) in the progenitors to investigate their impact on remnant evolution. The MBHs form hard binaries interacting with stars and stellar black holes (BHs). A few Myr after the cluster merger, this produces sizable populations of runaway stars (~800 with vej ≳ 50kms-1) and stellar BHs (~30) escaping within 100 Myr. The remnants lose ~30% of their BH population and ~3% of their stars, with ~30 stars accelerated to high velocities ≳ 300kms-1. Comparison simulations of isolated clusters with central hard MBH binaries and cluster mergers without MBHs show that the process is driven by MBH binaries, while those with a single 1000 M⊙ MBH in isolated or merging clusters produce fewer runaway stars at lower velocities. Low-eccentricity merger orbits yield rotating remnants (vrot ~ 3kms-1) , but probing the presence of MBHs via kinematics alone remains challenging. We expect the binary MBHs to merge within a Hubble time, producing observable gravitational-wave (GW) events detectable by future GW detectors such as the Einstein Telescope and LISA. The results suggest that interactions with low-mass MBH binaries formed in merging star clusters are an important additional channel for producing runaway and high-velocity stars, free-floating stellar BHs and compact objects.
Ongoing and upcoming wide-field surveys at different wavelengths will measure the distribution of galaxy clusters with unprecedented precision, demanding accurate models for the two-point correlation function (2PCF) covariance. In this work, we assess a semi-analytical framework for the cluster 2PCF covariance that employs three nuisance parameters to account for non-Poissonian shot noise, residual uncertainties in the halo bias model, and subleading noise terms. We calibrate these parameters on a suite of fast approximate simulations generated by PINOCCHIO as well as full $N$-body simulations from OpenGADGET3. We demonstrate that PINOCCHIO can reproduce the 2PCF covariance measured in OpenGADGET3 at the few percent level, provided the mass functions are carefully rescaled. Resolution tests confirm that high particle counts are necessary to capture shot-noise corrections, especially at high redshifts. We perform the parameter calibration across multiple cosmological models, showing that one of the nuisance parameters, the non-Poissonian shot-noise correction $\alpha$, depends mildly on the amplitude of matter fluctuations $\sigma_8$. In contrast, the remaining two parameters, $\beta$ controlling the bias correction and $\gamma$ controlling the secondary shot-noise correction, exhibit more significant variation with redshift and halo mass. Overall, our results underscore the importance of calibrating covariance models on realistic mock catalogs that replicate the selection function of forthcoming surveys and highlight that approximate methods, when properly tuned, can effectively complement full $N$-body simulations for precision cluster cosmology.
Cosmic shear, galaxy clustering, and the abundance of massive halos each probe the large-scale structure of the Universe in complementary ways. We present cosmological constraints from the joint analysis of the three probes, building on the latest analyses of the lensing-informed abundance of clusters identified by the South Pole Telescope (SPT) and of the auto- and cross-correlation of galaxy position and weak lensing measurements (<inline-formula><mml:math display="inline"><mml:mn>3</mml:mn><mml:mo>×</mml:mo><mml:mn>2</mml:mn><mml:mi>pt</mml:mi></mml:math></inline-formula>) in the Dark Energy Survey (DES). We consider the cosmological correlation between the different tracers and we account for the systematic uncertainties that are shared between the large-scale lensing correlation functions and the small-scale lensing-based cluster mass calibration. Marginalized over the remaining <inline-formula><mml:math display="inline"><mml:mi mathvariant="normal">Λ</mml:mi></mml:math></inline-formula> cold dark matter (<inline-formula><mml:math display="inline"><mml:mi mathvariant="normal">Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula>) parameters (including the sum of neutrino masses) and 52 astrophysical modeling parameters, we measure <inline-formula><mml:math display="inline"><mml:msub><mml:mi mathvariant="normal">Ω</mml:mi><mml:mi mathvariant="normal">m</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mn>0.300</mml:mn><mml:mo>±</mml:mo><mml:mn>0.017</mml:mn></mml:math></inline-formula> and <inline-formula><mml:math display="inline"><mml:msub><mml:mi>σ</mml:mi><mml:mn>8</mml:mn></mml:msub><mml:mo>=</mml:mo><mml:mn>0.797</mml:mn><mml:mo>±</mml:mo><mml:mn>0.026</mml:mn></mml:math></inline-formula>. Compared to constraints from Planck primary cosmic microwave background (CMB) anisotropies, our constraints are only 15% wider with a probability to exceed of 0.22 (<inline-formula><mml:math display="inline"><mml:mn>1.2</mml:mn><mml:mi>σ</mml:mi></mml:math></inline-formula>) for the two-parameter difference. We further obtain <inline-formula><mml:math display="inline"><mml:msub><mml:mi>S</mml:mi><mml:mn>8</mml:mn></mml:msub><mml:mo>≡</mml:mo><mml:msub><mml:mi>σ</mml:mi><mml:mn>8</mml:mn></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mi mathvariant="normal">Ω</mml:mi><mml:mi mathvariant="normal">m</mml:mi></mml:msub><mml:mo>/</mml:mo><mml:mn>0.3</mml:mn><mml:msup><mml:mo stretchy="false">)</mml:mo><mml:mn>0.5</mml:mn></mml:msup><mml:mo>=</mml:mo><mml:mn>0.796</mml:mn><mml:mo>±</mml:mo><mml:mn>0.013</mml:mn></mml:math></inline-formula> which is lower than the Planck measurement at the <inline-formula><mml:math display="inline"><mml:mn>1.6</mml:mn><mml:mi>σ</mml:mi></mml:math></inline-formula> level. The combined SPT cluster, DES <inline-formula><mml:math display="inline"><mml:mn>3</mml:mn><mml:mo>×</mml:mo><mml:mn>2</mml:mn><mml:mi>pt</mml:mi></mml:math></inline-formula>, and Planck datasets mildly prefer a nonzero positive neutrino mass, with a 95% upper limit <inline-formula><mml:math display="inline"><mml:mo>∑</mml:mo><mml:msub><mml:mi>m</mml:mi><mml:mi>ν</mml:mi></mml:msub><mml:mo><</mml:mo><mml:mn>0.25</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>eV</mml:mi></mml:math></inline-formula> on the sum of neutrino masses. Assuming a <inline-formula><mml:math display="inline"><mml:mi>w</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> model, we constrain the dark energy equation of state parameter <inline-formula><mml:math display="inline"><mml:mi>w</mml:mi><mml:mo>=</mml:mo><mml:mo>-</mml:mo><mml:mn>1.1</mml:mn><mml:msubsup><mml:mn>5</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.17</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.23</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> and when combining with Planck primary CMB anisotropies, we recover <inline-formula><mml:math display="inline"><mml:mi>w</mml:mi><mml:mo>=</mml:mo><mml:mo>-</mml:mo><mml:mn>1.2</mml:mn><mml:msubsup><mml:mn>0</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.09</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.15</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>, a <inline-formula><mml:math display="inline"><mml:mn>1.7</mml:mn><mml:mi>σ</mml:mi></mml:math></inline-formula> difference with a cosmological constant. The precision of our results highlights the benefits of multiwavelength multiprobe cosmology and our analysis paves the way for upcoming joint analyses of next-generation datasets.
We investigate cosmological correlators for conformally coupled ϕ4 theory in four-dimensional de Sitter space. These in-in correlators differ from scattering amplitudes for massless particles in flat space due to the spacelike structure of future infinity in de Sitter. They also require a regularization which preserves de Sitter-invariance, which makes the flat space limit subtle to define at loop-level. Nevertheless we find that up to two loops, the in-in correlators are structurally simpler than the wave function and have the same transcendentality as flat space amplitudes. Moreover, we show that their loop integrands can be recast in terms of flat space integrands and can be derived from a novel recursion relation.
Neutron supermirrors (SMs) are a crucial part of many scattering and particle physics experiments. So far, Ni(Mo)/Ti SMs have been used in experiments that require to transport a polarized neutron beam due to their lower saturation magnetization compared to Ni/Ti SMs. However, next generation $\beta$ decay experiments require SMs that depolarize below $10^{-4}$ per reflection to reach their targeted precision. The depolarization of a polarized neutron beam due to reflection from Ni(Mo)/Ti SMs has not yet been measured to that precision. Recently developed Cu/Ti SMs with a very low saturation magnetization compared to Ni(Mo)/Ti may serve as an alternative. In this paper, we test the performance of both mirrors. At a first stage, we present four-states polarized neutron reflectivity (PNR) curves of Ni(Mo) and Cu monolayers measured at the neutron reflectometer SuperADAM and perform a full polarization analysis, showing a difference between the magnetic scattering length density (mSLD) of both materials, with Cu having a lower mSLD than Ni(Mo). These results are corroborated with the full polarization analysis of four-states PNR curves of $m=2$ Ni(Mo)/Ti and Cu/Ti SMs. In a second stage, we measured the depolarization ($D$) that a polarized neutron beam suffers after reflection from the same Ni(Mo)/Ti and Cu/Ti SMs by using the Opaque Test Bench setup. We find upper limits for the depolarization of $D_\text{Cu/Ti(4N5)}<7.6\times 10^{-5}$, $D_\text{Ni(Mo)/Ti}<8.5\times 10^{-5}$, and $D_\text{Cu/Ti(2N6)}<6.0\times 10^{-5}$ at the $1\sigma$ confidence level, where (4N5) corresponds to a Ti purity of $99.995\%$ and (2N6) to $99.6\%$. The uncertainties are statistical. These results show that all three SMs are suitable for being used in next generation $\beta$ decay experiments. We found no noticeable dependence of $D$ on the $q$ value or the magnetizing field, in which the samples were placed.
Motivated by JWST observations of dense, clumpy and clustered high redshift star formation, we simulate the hierarchical assembly of nine $M_{\mathrm{cl}}=10^6 M_\odot$ star clusters using the BIFROST N-body code. Our low metallicity models ($0.01Z_\odot$) with post-Newtonian equations of motion for black holes include evolving populations of single, binary and triple stars. Massive stars grow by stellar collisions and collapse into intermediate mass black holes (IMBHs) up to $M_\mathrm{\bullet}\sim6200 M_\odot$, stellar multiplicity boosting the IMBH masses by a factor of $2$--$3$. The IMBHs tidally disrupt (TDE) $\sim50$ stars in $10$ Myr with peak TDE rates of $\Gamma\sim10^{-5}$ yr$^{-1}$ per cluster. These IMBHs are natural seeds for supermassive black holes (SMBHs) and the hierarchical assembly frequently leads to $>2$ SMBH seeds per cluster and their rapid mergers ($t<10$ Myr). We propose that a gravitational wave (GW) driven merger of IMBHs with $1000 M_\odot \lesssim M_\bullet \lesssim 10000 M_\odot$ with comparable masses is a characteristic GW fingerprint of SMBH seed formation at redshifts $z>10$, and IMBH formation in similar environments at lower redshifts. Massive star clusters provide a unique environment for the early Universe GW studies for the next-generation GW observatories including the Einstein Telescope and the Laser Interferometer Space Antenna.
[Abridged] Cassiopeia A (Cas A) provides a unique opportunity to study supernova (SN) dynamics and interactions with the circumstellar medium (CSM). Recent JWST observations revealed the "Green Monster" (GM), a structure with a likely CSM origin. We investigate its pockmarked morphology, characterized by circular holes and rings, by examining the role of small-scale ejecta structures interacting with a dense circumstellar shell. We adopted a neutrino-driven SN model to trace the evolution of its explosion from core collapse to the age of the Cas A remnant using high-resolution 3D magnetohydrodynamic simulations. Besides other processes, the simulations include self-consistent calculations of radiative losses, accounting for deviations from electron-proton temperature equilibration and ionization equilibrium, as well as the ejecta composition derived from the SN. The GM's morphology is reproduced by dense ejecta clumps and fingers interacting with an asymmetric, forward-shocked circumstellar shell. The clumps and fingers form by hydrodynamic instabilities growing at the interface between SN ejecta and shocked CSM. Radiative cooling accounting for effects of non-equilibrium of ionization enhances the ejecta fragmentation, forming dense knots and thin filamentary structures that penetrate the shell, producing a network of holes and rings with properties similar to those observed. The origin of the holes and rings in the GM can be attributed to the interaction of ejecta with a shocked circumstellar shell. By constraining the timing of this interaction and analyzing the properties of these structures, we provide a distinction of this scenario from an alternative hypothesis, which attributes these features to fast-moving ejecta knots penetrating the shell ahead of the forward shock.
Aims. We use Gaia DR3 astrometry and photometry to analyze the spatial distribution of the young stellar populations and stellar clusters and to search for new OB star candidates in the Carina Nebula complex and the full extent (∼5°, corresponding to ∼200 pc) of the Car OB1 association. Methods. We first performed a new census of high-mass stars in Car OB1 and compiled a comprehensive catalog of 517 stars with known spectral types (128 O-type, WR, and supergiant stars, and 389 B-type stars) that have Gaia DR3 parallaxes consistent with membership in the association. We applied the clustering algorithm DBSCAN on the Gaia DR3 data of the region to find stellar clusters, determine their distances and kinematics, and estimate ages. We also used Gaia astrometry and the additional astrophysical_parameters table to perform a spatially unbiased search for further high-mass members of Car OB1 over the full area of the association. Results. Our DBSCAN analysis finds 15 stellar clusters and groups in Car OB1, four of which were not known before. Most clusters (80%) show signs of expansion or contraction, four of them with a ≥2σ significance. We find a global expansion of the Car OB1 association with a velocity of vout = 5.25 ± 0.02 km s‑1. A kinematic traceback of the high-mass stars shows that the spatial extent of the association was at a minimum 3–4 Myr ago. Using astrophysical parameters by Gaia DR3, we identified 15 new O-type and 589 new B-type star candidates in Car OB1. The majority (≳54%) of the high-mass stars constitute a non-clustered distributed stellar population. Based on our sample of high-mass stars, we estimate a total stellar population of at least ∼8 × 104 stars in Car OB1. Conclusions. Our study is the first systematic astrometric analysis that covers the full spatial extent of the Car OB1 association, and it therefore substantially increases the knowledge of the distributed stellar population and spatial evolution of the entire association. Our results suggest suggests Car OB1 to be the most massive known star-forming complex in our Galaxy.
Radiation is crucial not only for observing astrophysical objects, but also for transporting energy and momentum. However, accurate on-the-fly radiation transport in astrophysical simulations is challenging and computationally expensive. Here we introduce AREPO-IDORT (Implicit Discrete Ordinates Radiation Transport), a scheme coupled to the explicit magnetohydrodynamic (MHD) solver in the 3D moving-mesh code AREPO. The discrete ordinates scheme means we directly solve for the specific intensities along discrete directions. We solve the time-dependent relativistic radiation transport equation via an implicit Jacobi-like iterative finite-volume solver, which overcomes the small radiation time-steps needed by explicit methods. Compared to commonly-used moment-based methods, e.g. flux-limited diffusion or M1 closure, this scheme has the advantage of correctly capturing the direction of radiation in both optically-thick and thin regions. It is based on the scheme by Jiang 2021 for the adaptive mesh refinement code ATHENA++, but we generalize the scheme to support (1) an unstructured moving-mesh, (2) local time-stepping, and (3) general equations of state. We show various test problems that commonly-used moment-based methods fail to reproduce accurately. To apply the scheme to a real astrophysics problem, we show the first global 3D radiation hydrodynamic simulation of the entire convective envelope of a red supergiant star. (abridged) For this problem, the radiation module only takes less than half of the total computational cost. Our current scheme assumes grey radiation, is first-order accurate in both time and space (abridged). We expect our scheme will enable more accurate multi-scale radiation MHD simulations involving supersonic bulk motions, ranging from planet formation in protoplanetary disks, stars and associated transients, to accretion flows near black holes.
Context. Brown dwarfs are the bridge between low-mass stars and giant planets. One way of shedding light on their dominant formation mechanism is to study them at the earliest stages of their evolution, when they are deeply embedded in their parental clouds. Several works have identified pre- and proto-brown dwarf candidates using different observational approaches. Aims. The aim of this work is to create a database of all the objects classified as very young substellar candidates in the literature in order to study them homogeneously. Methods. We gathered all the information about very young substellar candidates available in the literature until 2020. We retrieved their published photometry from the optical to the centimetre regime, and we wrote our own codes to derive their bolometric temperatures and luminosities, and their internal luminosities. We also populated the database with other parameters extracted from the literature, such as the envelope masses, their detection in some molecular species, and the presence of outflows. Results. The result of our search is the SUbstellar CANdidates at the Earliest Stages (SUCANES) database, containing 174 objects classified as potential very young substellar candidates in the literature. We present an analysis of the main properties of the retrieved objects. Since we updated the distances to several star forming regions, we were able to reject some candidates based on their internal luminosities. We also discuss the derived physical parameters and envelope masses for the best substellar candidates isolated in SUCANES. As an example of a scientific exploitation of this database, we present a feasibility study for the detection of radio jets with upcoming facilities: the next generation Very Large Array and the Square Kilometer Array interferometers. The SUCANES database is accessible through a graphical user interface, and it is open to any potential user.
We show how a method to construct canonical differential equations for multi-loop Feynman integrals recently introduced by some of the authors can be extended to cases where the associated geometry is of Calabi-Yau type and even beyond. This can be achieved by supplementing the method with information from the mixed Hodge structure of the underlying geometry. We apply these ideas to specific classes of integrals whose associated geometry is a one-parameter family of Calabi-Yau varieties, and we argue that the method can always be successfully applied to those cases. Moreover, we perform an in-depth study of the properties of the resulting canonical differential equations. In particular, we show that the resulting canonical basis is equivalent to the one obtained by an alternative method recently introduced in the literature. We apply our method to non-trivial and cutting-edge examples of Feynman integrals necessary for gravitational wave scattering, further showcasing its power and flexibility.
Cosmic-ray physics in the GeV-to-TeV energy range has entered a precision era thanks to recent data from space-based experiments. However, the poor knowledge of nuclear reactions, in particular for the production of antimatter and secondary nuclei, limits the information that can be extracted from these data, such as source properties, transport in the Galaxy and indirect searches for particle dark matter. The Cross-Section for Cosmic Rays at CERN workshop series has addressed the challenges encountered in the interpretation of high-precision cosmic-ray data, with the goal of strengthening emergent synergies and taking advantage of the complementarity and know-how in different communities, from theoretical and experimental astroparticle physics to high-energy and nuclear physics. In this paper, we present the outcomes of the third edition of the workshop that took place in 2024. We present the current state of cosmic-ray experiments and their perspectives, and provide a detailed road map to close the most urgent gaps in cross-section data, in order to efficiently progress on many open physics cases, which are motivated in the paper. Finally, with the aim of being as exhaustive as possible, this report touches several other fields -- such as cosmogenic studies, space radiation protection and hadrontherapy -- where overlapping and specific new cross-section measurements, as well as nuclear code improvement and benchmarking efforts, are also needed. We also briefly highlight further synergies between astroparticle and high-energy physics on the question of cross-sections.
Aims. We introduce the SISSI (Supernovae In a Stratified, Shearing Interstellar medium) simulation suite, which aims to enable a more comprehensive understanding of supernova remnants (SNRs) evolving in a complex interstellar medium (ISM) structured under the influence of galactic rotation, gravity and turbulence. Methods. We utilize zoom-in simulations of 30 SNRs expanding in the ISM of a simulated isolated disk galaxy. The ISM of the galaxy is resolved down to a maximum resolution of $\sim 12\,\text{pc}$, while we achieve a zoomed-in resolution of $\sim 0.18\, \text{pc}$ in the vicinity of the explosion sources. We compute the time-evolution of the SNRs' geometry and compare it to the observed geometry of the Local Bubble. Results. During the early stages of evolution, SNRs are well described by existing analytical models. On longer timescales, starting at about a percent of the orbital timescale, they depart from spherical symmetry and become increasingly prolate or oblate. The timescale for the departure from spherical symmetry is shorter than the expectation from a simple model for the deformation by galactic shear, suggesting that galactic shear alone cannot explain these differences. Yet, the alignment of the minor- and major axis of the SNRs is in line with expectations from said model, indicating that the deformation might have a shear-related origin. A comparison with the geometry of the Local Bubble reveals that it might be slightly younger than previously believed, but otherwise has a standard morphology for a SNR of its age and size. Conclusions. Studying the geometry of SNRs can reveal valuable insights about the complex interactions shaping their dynamical evolution. Future studies targeting the geometry of Galactic SNRs may use this insight to obtain a clearer picture of the processes shaping the Galactic ISM.
Neutrinos are the most abundant fundamental matter particles in the Universe and play a crucial role in particle physics and cosmology. Neutrino oscillation, discovered about 25 years ago, reveals that the three known species mix with each other. Anomalous results from reactor and radioactive-source experiments suggest a possible fourth neutrino state, the sterile neutrino, which does not interact via the weak force. The KATRIN experiment, primarily designed to measure the neutrino mass via tritium $\beta$-decay, also searches for sterile neutrinos suggested by these anomalies. A sterile-neutrino signal would appear as a distortion in the $\beta$-decay energy spectrum, characterized by a discontinuity in curvature (kink) related to the sterile-neutrino mass. This signature, which depends only on the shape of the spectrum rather than its absolute normalization, offers a robust, complementary approach to reactor experiments. KATRIN examined the energy spectrum of 36 million tritium $\beta$-decay electrons recorded in 259 measurement days within the last 40 electronvolt below the endpoint. The results exclude a substantial part of the parameter space suggested by the gallium anomaly and challenge the Neutrino-4 claim. Together with other neutrino-disappearance experiments, KATRIN probes sterile-to-active mass splittings from a fraction of an electron-volt squared to several hundred electron-volts squared, excluding light sterile neutrinos with mixing angles above a few percent.
The strongly lensed Supernova (SN) Encore at a redshift of $z = 1.949$, discovered behind the galaxy cluster MACS J0138$-$2155 at $z=0.336$, provides a rare opportunity for time-delay cosmography and studies of the SN host galaxy, where previously another SN, called SN Requiem, had appeared. To enable these studies, we combine new James Webb Space Telescope (JWST) imaging, archival Hubble Space Telescope (HST) imaging, and new Very Large Telescope (VLT) spectroscopic data to construct state-of-the-art lens mass models that are composed of cluster dark-matter (DM) halos and galaxies. We determine the photometric and structural parameters of the galaxies across six JWST and five HST filters. We use the color-magnitude and color-color relations of spectroscopically-confirmed cluster members to select additional cluster members, identifying a total of 84 galaxies belonging to the galaxy cluster. We construct seven different mass models using a variety of DM halo mass profiles, and explore both multi-plane and approximate single-plane lens models. As constraints, we use the observed positions of 23 multiple images from eight multiply lensed sources at four distinct spectroscopic redshifts. In addition, we use stellar velocity dispersion measurements to obtain priors on the galaxy mass distributions. We find that six of the seven models fit well to the observed image positions. Mass models with cored-isothermal DM profiles fit well to the observations, whereas the mass model with a Navarro-Frenk-White cluster DM profile has an image-position $\chi^2$ value that is four times higher. We build our ultimate model by combining four multi-lens-plane mass models and predict the image positions and magnifications of SN Encore and SN Requiem. Our work lays the foundation for building state-of-the-art mass models of the cluster for future cosmological analysis and SN host galaxy studies.
Precision spectroscopy of the electron spectrum of the tritium $\beta$-decay near the kinematic endpoint is a direct method to determine the effective electron antineutrino mass. The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine this quantity with a sensitivity of better than 0.3$\,$eV (90$\,$% C.L.). An inhomogeneous electric potential in the tritium source of KATRIN can lead to distortions of the $\beta$-spectrum, which directly impact the neutrino-mass observable. This effect can be quantified through precision spectroscopy of the conversion-electrons of co-circulated metastable $^{83m}$Kr. Therefore, dedicated, several-weeks long measurement campaigns have been performed within the KATRIN data taking schedule. In this work, we infer the tritium source potential observables from these measurements, and present their implications for the neutrino-mass determination.
Understanding the coevolution of supermassive black holes and their host galaxies requires tracing their growth over time. Mass measurements of distant black holes have been limited to active nuclei and commonly rely on spatially unresolved observations, leading to large uncertainties. Accurate masses can be determined by resolving the kinematics of stars within the sphere of influence, which has heretofore been possible only in the local universe. Using JWST, we have measured the mass $M_{\bullet}=6.0^{+2.1}_{-1.7}\times10^9$ ${\rm M}_{\odot}$ of an inactive black hole in a gravitationally lensed quiescent galaxy at redshift $z=1.95$, along with detailed host properties. Comparisons to local galaxies suggest that the correlation between $M_{\bullet}$ and bulge mass has evolved substantially, whereas the correlation with stellar velocity dispersion may have been in place for 10 Gyr.
A puzzling population of extremely massive quiescent galaxies at redshifts beyond z = 3 has recently been revealed by JWST and the Atacama Large Millimeter/submillimeter Array, some of them with stellar ages that show their quenching times to be as high as z = 6, while their stellar masses are already above 5 × 1010 M ⊙. These extremely massive yet quenched galaxies challenge our understanding of galaxy formation at the earliest stages. Using the hydrodynamical cosmological simulation suite Magneticum Pathfinder, we show that such massive quenched galaxies at high redshifts can be successfully reproduced with similar number densities as observed. The stellar masses, sizes, formation redshifts, and star formation histories of the simulated quenched galaxies match those determined with JWST. Following these quenched galaxies at z = 3.4 forward in time, we find 20% to be accreted onto a more massive structure by z = 2, and from the remaining 80% about 30% rejuvenate up to z = 2, another 30% stay quenched, and the remaining 40% rejuvenate on a very low level of star formation. Stars formed through rejuvenation are mostly formed on the outer regions of the galaxies, not in the centers. Furthermore, we demonstrate that the massive quenched galaxies do not reside in the most massive nodes of the cosmic web, but rather live in side nodes of approximately Milky Way halo mass. Even at z = 0, only about 10% end up in small-mass galaxy clusters, while most of the quenched galaxies at z = 3.4 end up in group-mass halos, with about 20% actually not even reaching 1013 M ⊙ in halo mass.
Our picture of galaxy evolution currently assumes that galaxies spend their life on the star formation main sequence until they may eventually be quenched. However, recent observations show indications that the full picture might be more complicated. We reveal how the star formation rates of galaxies evolve, possible causes and imprints of different evolution scenarios on galactic features. We follow the evolution of central galaxies in the highest-resolution box of the Magneticum Pathfinder cosmological hydrodynamical simulations and classify their evolution scenarios with respect to the star formation main sequence. We find that a major fraction of the galaxies undergoes long-term cycles of quenching and rejuvenation on Gyr timescales. This expands the framework of galaxy evolution from a secular evolution to a sequence of multiple active and passive phases. Only 14% of field galaxies on the star formation main sequence at z~0 actually evolved along the scaling relation, while the bulk of star forming galaxies in the local universe have undergone cycles of quenching and rejuvenation. In this work we describe the statistics of these galaxy evolution modes and how this impacts their stellar masses, ages and metallicities today. Galaxies with rejuvenation cycles can be distinguished well from main-sequence-evolved galaxies in their features at z~0. We further explore possible explanations and find that the geometry of gas accretion at the halo outskirts shows a strong correlation with the star formation rate evolution, while the density parameter as a tracer of environment shows no significant correlation. A derivation of star formation rates from gas accretion with simple assumptions only works reasonably well in the high-redshift universe where accreted gas gets quickly converted into stars.
We present a systematic method for analytically computing time-dependent observables for a relativistic probe particle in Coulomb and Schwarzschild backgrounds. The method generates expressions valid both in the bound and unbound regimes, namely bound-unbound universal expressions. To demonstrate our method we compute the time-dependent radius and azimuthal angle for relativistic motion in a Coulomb background (relativistic Keplerian motion), as well as the electromagnetic field radiated by a relativistic Keplerian source. All of our calculations exhibit bound-unbound universality. Finally, we present an exact expression for the semi-classical wave function in Schwarzschild. The latter is crucial in applying our method to any time-dependent observable for probe-limit motion in Schwarzschild, to any desired order in velocity and the gravitational constant $G$.
By employing the potential non-relativistic quantum chromodynamics (pNRQCD) effective field theory within an open quantum system framework, we derive a Lindblad equation governing the evolution of the heavy-quarkonium reduced density matrix, accurate to next-to-leading order (NLO) in the ratio of the state's binding energy to the medium's temperature [1]. The derived NLO Lindblad equation provides a more reliable description of heavy-quarkonium evolution in the quark-gluon plasma at low temperatures compared to the leading-order truncation. For phenomenological applications, we numerically solve this equation using the quantum trajectories algorithm. By averaging over Monte Carlo-sampled quantum jumps, we obtain solutions without truncation in the angular momentum quantum number of the considered states. Our analysis highlights the importance of quantum jumps in the nonequilibrium evolution of bottomonium states within the quark-gluon plasma [2]. Additionally, we demonstrate that the quantum regeneration of singlet states from octet configurations is essential to explain experimental observations of bottomonium suppression. The heavy-quarkonium transport coefficients used in our study align with recent lattice QCD determinations.
Cosmic birefringence (CB) is the rotation of the photons' linear polarisation plane during propagation. Such an effect is a tracer of parity-violating extensions of standard electromagnetism and would probe the existence of a new cosmological field acting as dark matter or dark energy. It has become customary to employ cosmic microwave background (CMB) polarised data to probe such a phenomenon. Recent analyses on Planck and WMAP data provide a hint of detection of the isotropic CB angle with an amplitude of around $0.3^\circ$ at the level of $2.4$ to $3.6\sigma$. In this work, we explore the LiteBIRD capabilities in constraining such an effect, accounting for the impact of the more relevant systematic effects, namely foreground emission and instrumental polarisation angles. We build five semi-independent pipelines and test these against four different simulation sets with increasing complexity in terms of non-idealities. All the pipelines are shown to be robust and capable of returning the expected values of the CB angle within statistical fluctuations for all the cases considered. We find that the uncertainties in the CB estimates increase with more complex simulations. However, the trend is less pronounced for pipelines that account for the instrumental polarisation angles. For the most complex case analysed, we find that LiteBIRD will be able to detect a CB angle of $0.3^\circ$ with a statistical significance ranging from $5$ to $13 \, \sigma$, depending on the pipeline employed, where the latter uncertainty corresponds to a total error budget of the order of $0.02^\circ$.
Aims. We investigate the role of cosmic ray (CR) halos in shaping the properties of starburst-driven galactic outflows. Methods. We develop a microphysical model for galactic outflows driven by a continuous central feedback source, incorporating a simplified treatment of CRs. The model parameters are linked to the effective properties of a starburst. By analyzing its asymptotic behavior, we derive a criterion for launching starburst-driven galactic outflows and determine the corresponding outflow velocities. Results. We find that in the absence of CRs, galactic outflows can only be launched if the star-formation rate (SFR) surface density exceeds a critical threshold proportional to the dynamical equilibrium pressure. In contrast, CRs can always drive slow outflows. CRs dominate in systems with SFR surface densities below the critical threshold but become negligible in highly star-forming systems. However, in older systems with established CR halos, the CR contribution to outflows diminishes once the outflow reaches the galactic scale height, rendering CRs ineffective in sustaining outflows in such systems. Conclusions. Over cosmic time, galaxies accumulate relic CRs in their halos, providing additional non-thermal pressure support that suppresses low-velocity CR-driven outflows. We predict that such low-velocity outflows are expected only in young systems that have not yet built up significant CR halos. In contrast, fast outflows in starburst galaxies, where the SFR surface density exceeds the critical threshold, are primarily driven by momentum injection and remain largely unaffected by CR halos.
It has been shown that proton ingestion episodes can happen in the formation of hot-subdwarf stars, and that neutron-capture processes are possible in those cases. Moreover, some helium-rich hot subdwarfs display extraordinarily high abundances of heavy elements such as Zr, Yr and Pb on their surfaces. We explore under which conditions neutron-capture processes can occur in late helium core flashes, i.e. those occurring in the cores of stripped red-giant stars. We compute evolutionary models through the helium core flash and the subsequent hydrogen ingestion episode in stripped red giant stars. Stellar structure models are then used in post-processing to compute the detailed evolution of neutron-capture elements. We find that for metallicities of $10^{-3}$ and below, neutron densities can be as high as $10^{15}\,$cm$^{-3}$ and intermediate neutron capture processes occur in some of our models. The results depend very strongly on the H-envelope mass that survives after the stripping. Interestingly, we find that computed abundances in some of our models closely match the element abundances up to tin observed for EC 22536-5304, the only well-studied star for which the hot-flasher scenario assumed in our models is the most likely evolutionary path. Intermediate neutron capture processes can occur in the He-core flash experienced by the cores of some stripped red giants, and might be connected to the abundances of heavy elements observed in some helium-rich hot-subdwarf stars. The agreement between the observed abundances in EC 22536-5304 and those of our models offers support to our nucleosynthesis calculations. Moreover, if confirmed, the idea that heavy element abundances retain signatures of the different evolutionary channels opens the possibility that heavy element abundances in iHe-sdOB stars can be used to infer their evolutionary origin.
The latest generation of cosmic-ray direct detection experiments is providing a wealth of high-precision data, stimulating a very rich and active debate in the community on the related strong discovery and constraining potentials on many topics, namely dark matter nature, and the sources, acceleration, and transport of Galactic cosmic rays. However, interpretation of these data is strongly limited by the uncertainties on nuclear and hadronic cross-sections. This contribution is one of the outcomes of the \textit{Cross-Section for Cosmic Rays at CERN} workshop series, that built synergies between experimentalists and theoreticians from the astroparticle, particle physics, and nuclear physics communities. A few successful and illustrative examples of CERN experiments' efforts to provide missing measurements on cross-sections are presented. In the context of growing cross-section needs from ongoing, but also planned, cosmic-ray experiments, a road map for the future is highlighted, including overlapping or complementary cross-section needs from applied topics (e.g., space radiation protection and hadrontherapy).
Data from particle physics experiments are unique and are often the result of a very large investment of resources. Given the potential scientific impact of these data, which goes far beyond the immediate priorities of the experimental collaborations that obtain them, it is imperative that the collaborations and the wider particle physics community publish and preserve sufficient information to ensure that this impact can be realised, now and into the future. The information to be published and preserved includes the algorithms, statistical information, simulations and the recorded data. This publication and preservation requires significant resources, and should be a strategic priority with commensurate planning and resource allocation from the earliest stages of future facilities and experiments.
[abridged] AGN feedback is a crucial ingredient for understanding galaxy evolution. However, a complete quantitative time-dependent framework, including the dependence of such feedback on AGN, host galaxy, and host halo properties, is yet to be developed. Using the complete sample of 682 radio AGN from the LOFAR-eFEDS survey ($z<0.4$), we derive the average jet power of massive galaxies and its variation as a function of stellar mass ($M_*$), halo mass ($M_h$) and radio morphology. We compare the incidence distributions of compact and complex radio AGN as a function of specific black hole kinetic power, $λ_{\rm Jet}$, and synthesise, for the first time, the radio luminosity function (RLF) by $M_*$ and radio morphology. Our RLF and derived total radio AGN kinetic luminosity density, $\log Ω_{\rm kin}/[\rm {W~Mpc^{-3}}]=32.15_{-0.34}^{+0.18}$, align with previous work. We find that kinetic feedback from radio AGN dominates over any plausible inventory of radiatively-driven feedback for galaxies with $\log M_*/M_\odot > 10.6$. More specifically, it is the compact radio AGN which dominate this global kinetic energy budget for all but the most massive galaxies ($10.6 < \log M_*/M_{\odot} < 11.5$). Subsequently, we compare the average injected jet energy against the galaxy and halo binding energy, and against the total thermal energy of the host gas within halos. We find that radio AGN cannot fully unbind their host galaxies nor host halos. However, they have enough energy to impact the global thermodynamical heating and cooling balance in small halos and significantly contribute to offsetting local cooling flows in even the most massive clusters cores. Overall, our findings provide important insights on jet powering, accretion processes and black hole-galaxy coevolution via AGN feedback, as well as a clear observational benchmark to calibrate AGN feedback simulations.
The measurement of the bound-state $β$ decay of $^{205}\mathrm{Tl}^{81+}$ at the Experimental Storage Ring at GSI, Darmstadt, has recently been reported with substantial impact on the use of $^{205}\mathrm{Pb}$ as an early Solar System chronometer and the low-energy measurement of the solar neutrino spectrum via the LOREX project. Due to the technical challenges in producing a high-purity $^{205}\mathrm{Tl}^{81+}$ secondary beam, a robust statistical method needed to be developed to estimate the variation in the contaminant $^{205}\mathrm{Pb}^{81+}$ produced during the fragmentation reaction. Here we show that Bayesian and Monte Carlo methods produced comparable estimates for the contaminant variation, each with unique advantages and challenges given the complex statistical problems for this experiment. We recommend the adoption of such methods in future experiments that exhibit unknown statistical fluctuations.
The Fornax cluster is one of the closest X-ray-bright galaxy clusters. Previous observations of the intracluster medium were limited to less than R500. We aim to significantly extend the X-ray coverage. We used data from 5 SRG/eROSITA all-sky surveys and performed a detailed 1- and 2-dimensional X-ray surface brightness analysis, tracing hot gas emission from kpc to Mpc scales with a single instrument. We compared the results to those from a recent numerical simulation of the local Universe (SLOW) and correlated the X-ray emission distribution with that of other tracers, including cluster member galaxies, ultra-compact dwarf galaxies, intracluster globular clusters, and HI-tail galaxies. We detect X-ray emission beyond the virial radius, R100=2.2 deg. In the inner regions within R500, we see previously known features, such as a large-scale spiral-shaped edge; however, we do not find obvious evidence of the bow shock several hundred kpc south of the cluster center predicted by previous numerical simulations of the Fornax cluster. Instead, we discover emission fingers beyond R500 to the west and southeast and excesses that stretch out far beyond the virial radius. They might be due to gas being pushed outward by the previous merger with NGC 1404 or due to warm-hot gas infall along large-scale filaments. Intriguingly, we find the distributions of the other tracers - galaxies and globular clusters - to be correlated with the X-ray-excess regions, favoring the infall scenario. Interestingly, we also discover an apparent bridge of low-surface-brightness emission beyond the virial radius connecting to the Fornax A galaxy group, which is also traced by the member galaxy and globular cluster distribution. The gas distribution in the SLOW simulation shows similar features as those we have discovered with eROSITA. With eROSITA, we witness the growth of a cluster along large-scale filaments.
The basic observables in cosmology are known as in-in correlators. Recent calculations have revealed that in-in correlators in four dimensional de Sitter space exhibit hidden simplicity stemming from a close relation to scattering amplitudes in flat space. In this paper we explain how to make this property manifest by dressing flat space Feynman diagrams with certain auxiliary propagators. These dressing rules hold for any order in perturbation theory and can be derived for a broad range of scalar theories, including those with infrared divergences. In the latter case we show that they reproduce the same infrared divergences predicted by the Schwinger-Keldysh formalism.
This thesis presents a comprehensive investigation of the modeling uncertainties
of asymptotic giant branch (AGB) stellar evolution and nucleosynthesis through
the examination of two key nucleosynthetic processes: the intermediate and slow
neutron-capture processes (i-process and s-process). The research combines stel-
lar evolution modeling with detailed post-processing nucleosynthesis calculations
to advance our understanding of heavy element production in the universe.
To study the i-process, I run a grid of models with different overshoot val-
ues and masses. A proton ingestion event (PIE) is found to occur in low-mass,
low-metallicity stars even without overshoot. I develop and validate a novel
timescale-based criterion for determining when PIEs occur in stellar models. I
find that diffusive overshooting significantly influences both PIE occurrence and
characteristics. The timing of the split of the pulse driven convection zone (PDCZ)
during a PIE crucially affects the final surface abundances. Comparison of the
modeled and observed surface abundances show that the models overproduce
carbon and have difficulty in matching the first-peak element abundances of
CEMP-r/s stars. A key finding is the identification of “failed” i-process events as a
potential explanation for both some CEMP-r/s and CEMP-s stars, suggesting a
more nuanced picture of heavy element production in metal-poor AGB stars.[...]
We investigate electromagnetically interacting spin-1/2 DM particles by comparing the theoretical prediction with the reach of DM direct detection experiments. We evaluate the one-loop contributions for scalar- and vector-portal models, which are valid for Dirac and Majorana DM. We apply the model-independent results to the lightest neutralino and a Dirac toy model. Finally, we discuss the SM prediction for the EM interactions of neutrinos and characterize additional possible BSM contributions.
We apply the cobordism hypothesis with singularities to the case of affine Rozansky-Witten models, providing a construction of extended TQFTs that includes all line and surface defects. On a technical level, this amounts to proving that the associated homotopy 2-category is pivotal, and to systematically employing its 3-dimensional graphical calculus. This in particular allows us to explicitly calculate state spaces for surfaces with arbitrary defect networks. As specific examples we discuss symmetry defects which can be used to model non-trivial background gauge fields, as well as boundary conditions.
The interaction of relativistic particles with plasma, relevant to astrophysics and laboratory-based plasma wakefield accelerators, is governed by plasma instabilities leading to electromagnetic fluctuations and filamentary structures. Wakefield-driven and current-driven instabilities of particle beams with a well-defined extent are analysed through theory and particle-in-cell simulations and compared to experimental observations, providing a basis for experimental designs.
We compute analytically the three-loop correlation function of the local operator tr ϕ3 inserted into three on-shell states, in maximally supersymmetric Yang-Mills theory. The result is expressed in terms of Chen iterated integrals. We also present our result using generalised polylogarithms, and evaluate them numerically, finding agreement with a previous numerical result in the literature. We observe that the result depends on fewer kinematic singularities compared to individual Feynman integrals. Furthermore, upon choosing a suitable definition of the finite part, we find that the latter satisfies powerful symbol adjacency relations similar to those previously observed for the tr ϕ2 case.
Strongly lensed quasars provide valuable insights into the rate of cosmic expansion, the distribution of dark matter in foreground deflectors, and the characteristics of quasar hosts. However, detecting them in astronomical images is difficult due to the prevalence of non-lensing objects. To address this challenge, we developed a generative deep learning model called VariLens, built upon a physics-informed variational autoencoder. This model seamlessly integrates three essential modules: image reconstruction, object classification, and lens modeling, offering a fast and comprehensive approach to strong lens analysis. VariLens is capable of rapidly determining both (1) the probability that an object is a lens system and (2) key parameters of a singular isothermal ellipsoid (SIE) mass model – including the Einstein radius (θE), lens center, and ellipticity – in just milliseconds using a single CPU. A direct comparison of VariLens estimates with traditional lens modeling for 20 known lensed quasars within the Subaru Hyper Suprime-Cam (HSC) footprint shows good agreement, with both results consistent within 2σ for systems with θE < 3″. To identify new lensed quasar candidates, we began with an initial sample of approximately 80 million sources, combining HSC data with multiwavelength information from Gaia, UKIRT, VISTA, WISE, eROSITA, and VLA. After applying a photometric preselection aimed at locating z > 1.5 sources, the number of candidates was reduced to 710 966. Subsequently, VariLens highlights 13 831 sources, each showing a high likelihood of being a lens. A visual assessment of these objects results in 42 promising candidates that await spectroscopic confirmation. These results underscore the potential of automated deep learning pipelines to efficiently detect and model strong lenses in large datasets, substantially reducing the need for manual inspection.
We present a computation of the one-loop QCD corrections to top-quark pair production in association with a $W$ boson, including terms up to order $\varepsilon^2$ in dimensional regularization. Providing a first glimpse into the complexity of the corresponding two-loop amplitude, this result is a first step towards a description of this process at next-to-next-to-leading order (NNLO) in QCD. We perform a tensor decomposition and express the corresponding form factors in terms of a basis of independent special functions with compact rational coefficients, providing a structured framework for future developments. In addition, we derive an explicit analytic representation of the form factors, valid up to order $\varepsilon^0$, expressed in terms of logarithms and dilogarithms. For the complete set of special functions required, we obtain a semi-numerical solution based on generalized power series expansion.
The post-inflationary Peccei-Quinn (PQ) symmetry breaking scenario provides a unique opportunity to pinpoint the QCD axion dark matter mass, which is a crucial input for laboratory experiments that are designed for probing specific mass ranges. Predicting their mass requires a precise knowledge of how axions are produced from the decay of topological defects in the early Universe that are inevitably formed. In this contribution, we present recent results on the analysis of the spectrum of axions radiated from global strings based on large scale numerical simulations of the cosmological evolution of the PQ field on a static lattice. We highlight several systematic effects that have been overlooked in previous works, such as the dependence on the initial conditions, contaminations due to oscillations in the spectrum, and discretisation effects; some of which could explain the discrepancy in the current literature. Taking these uncertainties into account and performing the extrapolation to cosmologically relevant string tensions, we find that the dark matter mass is predicted to be in the range of $95\,\mu\text{eV} \lesssim m_a \lesssim 450 \, \mu\text{eV}$, which will be probed by some of the next generation direct detection experiments.
We have observed the late Class I protostellar source Elias 29 at a spatial resolution of 70 au with the Atacama Large Millimeter/submillimeter Array as part of the FAUST Large Program. We focus on the line emission of SO, while that of 34SO, C18O, CS, SiO, H13CO+, and DCO+ are used supplementarily. The spatial distribution of the SO rotational temperature (Trot(SO)) is evaluated by using the intensity ratio of its two rotational excitation lines. Besides in the vicinity of the protostar, two hot spots are found at a distance of 500 au from the protostar; Trot(SO) locally rises to 53<inline-formula> </inline-formula> K at the interaction point of the outflow and the southern ridge, and 72<inline-formula> </inline-formula> K within the southeastern outflow probably due to a jet-driven bow shock. However, the SiO emission is not detected at these hot spots. It is likely that active gas accretion through the disk-like structure and onto the protostar still continues even at this evolved protostellar stage, at least sporadically, considering the outflow/jet activities and the possible infall motion previously reported. Interestingly, Trot(SO) is as high as 20–30 K even within the quiescent part of the southern ridge apart from the protostar by 500–1000 au without clear kinematic indication of current outflow/jet interactions. Such a warm condition is also supported by the low deuterium fractionation ratio of HCO+ estimated by using the H13CO+ and DCO+ lines. The B-type star HD147889 ∼0.5 pc away from Elias 29, previously suggested as a heating source for this region, is likely responsible for the warm condition of Elias 29.
In this paper, we define absorptive Compton amplitudes, which capture the absorption factor for waves of spin-weight-<inline-formula><mml:math display="inline"><mml:mi>s</mml:mi></mml:math></inline-formula> scattering in black hole perturbation theory. At the leading order, in the <inline-formula><mml:math display="inline"><mml:mi>G</mml:mi><mml:mi>M</mml:mi><mml:mi>ω</mml:mi></mml:math></inline-formula> expansion, such amplitudes are purely imaginary and expressible as contact terms. Equipped with these amplitudes we compute the mass change in black hole scattering events via the Kosower-Maybee-O'Connell formalism, where the rest mass of a Schwarzschild/Kerr black hole is modified due to absorption of gravitational, electromagnetic, or scalar fields sourced by other compact object. We reproduced the power loss previously computed in the post-Newtonian expansion. The results presented here hold for similar mass ratios and generic spin orientation, while keeping the Kerr spin parameter to lie in the physical region <inline-formula><mml:math display="inline"><mml:mi>χ</mml:mi><mml:mo>≤</mml:mo><mml:mn>1</mml:mn></mml:math></inline-formula>.