We revisit our previous work [Capozzi et al., Phys. Rev. D 95, 096014 (2017), 10.1103/PhysRevD.95.096014] where neutrino oscillation and nonoscillation data were analyzed in the standard framework with three neutrino families, in order to constrain their absolute masses and to probe their ordering (either normal, NO, or inverted, IO). We include updated oscillation results to discuss best fits and allowed ranges for the two squared mass differences δ m2 and Δ m2, the three mixing angles θ12, θ23, and θ13, as well as constraints on the C P -violating phase δ , plus significant indications in favor of NO vs IO at the level of Δ χ2=10.0 . We then consider nonoscillation data from beta decay, from neutrinoless double beta decay (if neutrinos are Majorana), and from various cosmological input variants (in the data or the model) leading to results dubbed as default, aggressive, and conservative. In the default option, we obtain from nonoscillation data an extra contribution Δ χ2≃2.2 in favor of NO, and an upper bound on the sum of neutrino masses Σ <0.15 eV at 2 σ ; both results—dominated by cosmology—can be strengthened or weakened by using more aggressive or conservative options, respectively. Taking into account such variations, we find that the combination of all (oscillation and nonoscillation) neutrino data favors NO at the level of 3.2 -3.7 σ , and that Σ is constrained at the 2 σ level within Σ <0.12 - 0.69 eV . The upper edge of this allowed range corresponds to an effective β -decay neutrino mass mβ≃Σ /3 ≃0.23 eV , at the sensitivity frontier of the KATRIN experiment.
Neutrinos are unique probes of core-collapse supernova dynamics, especially in the case of black hole (BH-)forming stellar collapses, where the electromagnetic emission may be faint or absent. By investigating two three-dimensional hydrodynamical simulations of BH-forming stellar collapses of mass 40 M⊙ and 75 M⊙, we identify the physical processes preceding BH formation through neutrinos and forecast the neutrino signal expected in the existing IceCube and Super-Kamiokande detectors, as well as in the future generation DUNE facility. Prior to the abrupt termination of the neutrino signal corresponding to BH formation, both models develop episodes of strong and long-lasting activity by the spiral standing accretion shock instability (SASI). We find that the spiral SASI peak in the Fourier power spectrum of the neutrino event rate will be distinguishable at 3 σ above the detector noise for distances up to ∼O (30 ) kpc in the most optimistic scenario, with IceCube having the highest sensitivity. Interestingly, given the long duration of the spiral SASI episodes, the spectrograms of the expected neutrino event rate carry clear signs of the evolution of the spiral SASI frequency as a function of time, as the shock radius and postshock fluid velocity evolve. Because of the high accretion luminosity and its large-amplitude SASI-induced modulations, any contribution from asymmetric (dipolar or quadrupolar) neutrino emission associated with the lepton emission self-sustained asymmetry is far subdominant in the neutrino signal.
This is the first advanced, systematic and comprehensive look at weak decays in the framework of gauge theories. Included is a large spectrum of topics, both theoretical and experimental. In addition to explicit advanced calculations of Feynman diagrams and the study of renormalization group strong interaction effects in weak decays, the book is devoted to the Standard Model Effective Theory, dominating present phenomenology in this field, and to new physics models with the goal of searching for new particles and interactions through quantum fluctuations. This book will benefit theorists, experimental researchers, and Ph.D. students working on flavour physics and weak decays as well as physicists interested in physics beyond the Standard Model. In its concern for the search for new phenomena at short distance scales through the interplay between theory and experiment, this book constitutes a travel guide to physics far beyond the scales explored by the Large Hadron Collider at CERN.
We calculate the step-scaling function, the lattice analog of the renormalization group β -function, for an SU(3) gauge theory with ten fundamental flavors. We present a detailed analysis including the study of systematic effects of our extensive data set generated with ten dynamical flavors using the Symanzik gauge action and three times stout smeared Möbius domain wall fermions. Using up to 324 volumes, we calculate renormalized couplings for different gradient flow schemes and determine the step-scaling β function for a scale change s =2 on up to five different lattice volume pairs. In an accompanying paper we discuss that gradient flow can promote lattice dislocations to instantonlike objects, introducing nonperturbative lattice artifacts to the step-scaling function. Motivated by the observation that Wilson flow sufficiently suppresses these artifacts, we choose Wilson flow with the Symanzik operator as our preferred analysis. We study systematic effects by calculating the step-scaling function based on alternative flows (Zeuthen or Symanzik), alternative operators (Wilson plaquette, clover), and also explore the effects of the perturbative tree-level improvement. Further we investigate the effects due to the finite value of Ls.
We study stellar property statistics, including satellite galaxy occupation, of haloes in three cosmological hydrodynamics simulations: BAHAMAS + MACSIS, IllustrisTNG, and Magneticum Pathfinder. Applying localized linear regression, we extract halo mass-conditioned normalizations, slopes, and intrinsic covariance for (i) Nsat, the number of stellar mass-thresholded satellite galaxies within radius R200c of the halo; (ii) M⋆,tot, the total stellar mass within that radius, and (iii) M⋆,BCG, the gravitationally bound stellar mass of the central galaxy within a 100 kpc radius. The parameters show differences across the simulations, in part from numerical resolution, but there is qualitative agreement for the Nsat - M⋆,BCG correlation. Marginalizing over Mhalo, we find the Nsat kernel, p(ln Nsat | Mhalo,z) to be consistently skewed left in all three simulations, with skewness parameter γ = -0.91 ± 0.02, while the M⋆,tot kernel shape is closer to lognormal. The highest resolution simulations find γ ≃ -0.8 for the z = 0 shape of the M⋆,BCG kernel. We provide a Gaussian mixture fit to the low-redshift Nsat kernel as well as local linear regression parameters tabulated for Mhalo > 1013.5 M⊙ in all simulations.
The Fundamental Plane (FP) of black hole (BH) activity in galactic nuclei relates X-ray and radio luminosities to BH mass and accretion rate. However, there is a large scatter exhibited by the data, which motivated us for a new variable. We add BH spin as a new variable and estimate the spin dependence of the jet power and disc luminosity in terms of radio and X-ray luminosities. We assume the Blandford-Znajek process as the main source of the outflow, and find that the jet power depends on BH spin stronger than quadratically at moderate and large spin values. We perform a statistical analysis for 10 active galactic nuclei (AGNs) which have sub-Eddington accretion rates and whose spin values are measured independently via the reflection or continuum-fitting methods, and find that the spin-dependent relation describes the data significantly better. This analysis, if supported with more data, could imply not only the spin dependence of the FP relation, but also the Blandford-Znajek process in AGN jets.
In the presence of an external magnetic field, the axion and the photon mix. In particular, the dispersion relation of a longitudinal plasmon always crosses the dispersion relation of the axion (for small axion masses), thus leading to a resonant conversion. Using thermal field theory, we concisely derive the axion emission rate, applying it to astrophysical and laboratory scenarios. For the Sun, depending on the magnetic field profile, plasmon-axion conversion can dominate over Primakoff production at low energies (≲200 eV ). This both provides a new axion source for future helioscopes and, in the event of discovery, would probe the magnetic field structure of the Sun. In the case of white dwarfs (WDs), plasmon-axion conversion provides a pure photon coupling probe of the axion, which may contribute significantly for low-mass WDs. Finally, we rederive and confirm the axion absorption rate of the recently proposed plasma haloscopes.
We study the bottomonium spectrum using a relativistic potential model in the momentum space. This model is based on a complete one gluon exchange interaction with a momentum dependent screening factor to account for the effects due to virtual pair creation that appear close to the decay thresholds. The overall model does not make use of nonrelativistic approximations. We fit well established bottomonium states below the open bottom threshold and predict the rest of the spectrum up to ≈11200 MeV and JPC=3-- . Uncertainties are treated rigorously and propagated in full to the parameters of the model using a Monte Carlo to identify if which deviations from experimental data can be absorbed into the statistical uncertainties of the models and which can be related to physics beyond the b b ¯ picture, guiding future research. We get a good description of the spectrum, in particular the Belle measurement of the ηb(2 S ) state and the Υ (10860 ) and χb(3 P ) resonances.
In this paper we examine the viability of inflation models with a spectator axion field coupled to both gravitational and SU(2) gauge fields via Chern-Simons couplings. Requiring phenomenological success of the axion-SU(2) sector constrains the coupling strength of the gravitational Chern-Simons term. We find that the impact of this term on the production and propagation of gravitational waves can be as large as fifty percent enhancement for the helicity that is not sourced by the gauge field, if the cut-off scale is as low as Λ = 20H. The effect becomes smaller for a larger value of Λ, while the impact on the helicity sourced by the gauge field is negligible regardless of Λ.
We revisit techniques for performing cosmological simulations with both baryons and cold dark matter when each fluid has different initial conditions, as is the case at the end of the radiation era. Most simulations do not reproduce the linear prediction for the difference between the cold dark matter and baryon perturbations. We show that this is due to the common use of offset regular grids when setting up the particle initial conditions. The desired linear evolution can be obtained without any loss of simulation resolution by using a Lagrangian glass for the baryon particles. We further show that the difference between cold dark matter and baryons may affect predictions for the Lyman-α forest flux power spectrum at the 5% level, potentially impacting current cosmological constraints.
We use functional methods to compute one-loop effects in Heavy Quark Effective Theory. The covariant derivative expansion technique facilitates the efficient extraction of matching coefficients and renormalization group evolution equations. This paper pro- vides the first demonstration that such calculations can be performed through the algebraic evaluation of the path integral for the class of effective field theories that are (i) constructed using a non-trivial one-to-many mode decomposition of the UV theory, and (ii) valid for non-relativistic kinematics. We discuss the interplay between operators that appear at intermediate steps and the constraints imposed by the residual Lorentz symmetry that is encoded as reparameterization invariance within the effective description. The tools presented here provide a systematic approach for computing corrections to higher order in the heavy mass expansion; precision applications include predictions for experimental data and connections to theoretical tests via lattice QCD. A set of pedagogical appendices comprehensively reviews modern approaches to performing functional calculations algebraically, and derives contributions from a term with open covariant derivatives for the first time.
Upcoming surveys will use a variety of galaxy selections to map the large-scale structure of the Universe. It is important to make accurate predictions for the properties and clustering of such galaxies, including the errors on these statistics. Here, we describe a novel technique which uses the semi-analytical model of galaxy formation galform, embedded in the high-resolution N-body Planck-Millennium simulation, to populate a thousand halo catalogues generated using the Parallel-PM N-body glam code. Our hybrid scheme allows us to make clustering predictions on scales that cannot be modelled in the original N-body simulation. We focus on luminous red galaxies (LRGs) selected in the redshift range z = 0.6 − 1 from the galform output using similar colour-magnitude cuts in the r, z, and W1 bands to those that will be applied in the Dark Energy Spectroscopic Instrument (DESI) survey, and call this illustrative sample ‘DESI-like’ LRGs. We find that the LRG-halo connection is non-trivial, leading to the prediction of a non-standard halo occupation distribution; in particular, the occupation of central galaxies does not reach unity for the most massive haloes, and drops with increasing mass. The glam catalogues reproduce the abundance and clustering of the LRGs predicted by galform. We use the glam mocks to compute the covariance matrices for the two-point correlation function and power spectrum of the LRGs and their background dark matter density field, revealing important differences. We also make predictions for the linear-growth rate and the baryon acoustic oscillations distances at z = 0.6, 0.74, and 0.93. All ‘DESI-like’ LRG catalogues are made publicly available.
It has been argued that the symmetries of gravity at null infinity should include a Diff (S2) factor associated with diffeomorphisms on the celestial sphere. However, the standard phase space of gravity does not support the action of such transformations. Building on earlier work by Laddha and one of the authors, we present an extension of the phase space of gravity at null infinity on which Diff (S2) acts canonically. The Poisson brackets of supertranslation and Diff (S2) charges reproduce the generalized BMS algebra introduced in [Campiglia and Laddha Phys. Rev. D 90, 124028 (2014), 10.1103/PhysRevD.90.124028].
The relation between early type galaxy size, surface brightness and velocity dispersion, ``the fundamental plane", has long been understood as resulting from equilibrium in their largely pressure supported stellar dynamics. The dissipation and feedback involved in reaching such an equilibrium through merger formation of these galaxies over cosmic time can be responsible for the orientation of the plane. We see a correlation between surface brightness enhancement and youth in the 6dF Galaxy Survey. Correlations of this `tilt' with stellar mass, age, concentration, shape and metallicity now point the direction for further work on the resolved kinematics and structure of these nearby galaxies and on their initial mass function and dark matter component. On the face of it, the Tully Fisher relation is a simpler one dimensional scaling relation. However, as late type galaxies have bulges as well as disks, and, as the surface density of disks is only standard for the more massive galaxies, additional parameters are involved.
We study the K ¯ p →Y K K ¯ π reactions with K ¯ =K¯ 0,K- and Y =Σ0,Σ+,Λ , in the region of K K ¯ π invariant masses of 1200 -1550 MeV. The strong coupling of the f1(1285 ) resonance to K∗K ¯ makes the mechanism based on K∗ exchange very efficient to produce this resonance observed in the K K ¯ π invariant mass distribution. In addition, in all these reactions one observes an associated peak at 1420 MeV which comes from the K∗K ¯ decay mode of the f1(1285 ) when the K∗ is placed on shell at higher invariant masses. We call the attention to the possibility that the peaks observed in other reactions where the "f1(1420 ) " is observed have a similar origin.
The abundance of galaxy clusters as a function of mass and redshift is a well known powerful cosmological probe, which relies on underlying modelling assumptions on the mass-observable relations (MOR). Some of the MOR parameters can be constrained directly from multi-wavelength observations, as the normalization at some reference cosmology, the mass-slope, the redshift evolution, and the intrinsic scatter. However, the cosmology dependence of MORs cannot be tested with multi-wavelength observations alone. We use magneticum simulations to explore the cosmology dependence of galaxy cluster scaling relations. We run fifteen hydrodynamical cosmological simulations varying Ωm, Ωb, h0, and σ8 (around a reference cosmological model). The MORs considered are gas mass, baryonic mass, gas temperature, Y and velocity dispersion as a function of virial mass. We verify that the mass and redshift slopes and the intrinsic scatter of the MORs are nearly independent of cosmology with variations significantly smaller than current observational uncertainties. We show that the gas mass and baryonic mass sensitively depends only on the baryon fraction, velocity dispersion, and gas temperature on h0, and Y on both baryon fraction and h0. We investigate the cosmological implications of our MOR parametrization on a mock catalogue created for an idealized eROSITA-like experiment. We show that our parametrization introduces a strong degeneracy between the cosmological parameters and the normalization of the MOR. Finally, the parameter constraints derived at different overdensity (Δ500c), for X-ray bolometric gas luminosity, and for different subgrid physics prescriptions are shown in the appendix.
Several types/classes of shocks naturally arise during formation and evolution of galaxy clusters. One such class is represented by accretion shocks, associated with deceleration of infalling baryons. Such shocks, characterized by a very high Mach number, are present even in 1D models of cluster evolution. Another class is composed of 'runaway merger shocks', which appear when a merger shock, driven by a sufficiently massive infalling subcluster, propagates away from the main-cluster centre. We argue that, when the merger shock overtakes the accretion shock, a new long-living shock is formed that propagates to large distances from the main cluster (well beyond its virial radius), affecting the cold gas around the cluster. We refer to these structures as Merger-accelerated Accretion shocks (MA-shocks) in this paper. We show examples of such MA-shocks in one-dimensioanal (1D) and three-dimensional (3D) simulations and discuss their characteristic properties. In particular, (1) MA-shocks shape the boundary separating the hot intracluster medium (ICM) from the unshocked gas, giving this boundary a 'flower-like' morphology. In 3D, MA-shocks occupy space between the dense accreting filaments. (2) Evolution of MA-shocks highly depends on the Mach number of the runaway merger shock and the mass accretion rate parameter of the cluster. (3) MA-shocks may lead to the misalignment of the ICM boundary and the splashback radius.
We calculate the masses of χc(3 P ) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of χc(2 P ) and χb(3 P ) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the χc(3 P ) states and their radiative transitions. According to our predictions, the χc(3 P ) states should be dominated by the charmonium core, but they may also show small meson-meson components. The X(4274) is interpreted as a c c ¯ χc 1(3 P ) state. More information on the other members of the χc(3 P ) multiplet, as well as a more rigorous analysis of the X(4274)'s decay modes, are needed to provide further indications on the quark structure of the previous resonance.
Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the b → cℓν and b → sℓℓ transitions, as observed in recent years. While not required to explain the anomalies, these leptoquarks generically yield new sources of CP violation. In this paper, we explore constraints and discovery potential for electric dipole moments (EDMs) in leptonic and hadronic systems. We provide the most generic expressions for dipole moments induced by vector leptoquarks at one loop. We find that O(1) CP-violating phases in tau and muon couplings can lead to corresponding EDMs within reach of next-generation EDM experiments, and that existing bounds on the electron EDM already put stringent constraints on CP-violating electron couplings.
We investigate the build-up of the galactic dynamo and subsequently the origin of a magnetic driven outflow. We use a set-up of an isolated disc galaxy with a realistic circum-galactic medium (CGM). We find good agreement of the galactic dynamo with theoretical and observational predictions from the radial and toroidal components of the magnetic field as function of radius and disc scale height. We find several field reversals indicating dipole structure at early times and quadrupole structure at late times. Together with the magnetic pitch angle and the dynamo control parameters Rα, Rω, and D, we present strong evidence for an α2-Ω dynamo. The formation of a bar in the centre leads to further amplification of the magnetic field via adiabatic compression which subsequently drives an outflow. Due to the Parker instability the magnetic field lines rise to the edge of the disc, break out, and expand freely in the CGM driven by the magnetic pressure. Finally, we investigate the correlation between magnetic field and star formation rate. Globally, we find that the magnetic field is increasing as function of the star formation rate surface density with a slope between 0.3 and 0.45 in good agreement with predictions from theory and observations. Locally, we find that the magnetic field can decrease while star formation increases. We find that this effect is correlated with the diffusion of magnetic field from the spiral arms to the interarm regions which we explicitly include by solving the induction equation and accounting for non-linear terms.
We estimate the H I mass function (HIMF) of galaxies in groups based on thousands of ALFALFA (Arecibo Legacy Fast ALFA survey) H I detections within the galaxy groups of four widely used SDSS (Sloan Digital Sky Survey) group catalogues. Although differences between the catalogues mean that there is no one definitive group galaxy HIMF, in general we find that the low-mass slope is flat, in agreement with studies based on small samples of individual groups, and that the 'knee' mass is slightly higher than that of the global HIMF of the full ALFALFA sample. We find that the observed fraction of ALFALFA galaxies in groups is approximately 22 per cent. These group galaxies were removed from the full ALFALFA source catalogue to calculate the field HIMF using the remaining galaxies. Comparison between the field and group HIMFs reveals that group galaxies make only a small contribution to the global HIMF as most ALFALFA galaxies are in the field, but beyond the HIMF 'knee' group galaxies dominate. Finally, we attempt to separate the group galaxy HIMF into bins of group halo mass, but find that too few low-mass galaxies are detected in the most massive groups to tightly constrain the slope, owing to the rarity of such groups in the nearby Universe where low-mass galaxies are detectable with existing H I surveys.
We present accurate measurements of the total H I mass in dark matter halos of different masses at z ∼ 0, by stacking the H I spectra of entire groups from the Arecibo Fast Legacy ALFA Survey. The halos are selected from the optical galaxy group catalog constructed from the Sloan Digital Sky Survey DR7 Main Galaxy sample, with reliable measurements of halo mass and halo membership. We find that the H I-halo mass relation is not a simple monotonic function, as assumed in several theoretical models. In addition to the dependence of halo mass, the total H I gas mass shows a strong dependence on the halo richness, with larger H I masses in groups with more members at fixed halo masses. Moreover, halos with at least three member galaxies in the group catalog have a sharp decrease of the H I mass, potentially caused by the virial halo shock-heating and the active galactic nucleus (AGN) feedback. The dominant contribution of the H I gas comes from the central galaxies for halos of ${M}_{{\rm{h}}}\lt {10}^{12.5}{h}^{-1}{M}_{\odot }$ , while the satellite galaxies dominate over more massive halos. Our measurements are consistent with a three-phase formation scenario of the H I-rich galaxies. The smooth cold gas accretion is driving the H I mass growth in halos of ${M}_{{\rm{h}}}\lt {10}^{11.8}{h}^{-1}{M}_{\odot }$ , with late-forming halos having more H I accreted. The virial halo shock-heating and AGN feedback will take effect to reduce the H I supply in halos of ${10}^{11.8}{h}^{-1}{M}_{\odot }\lt {M}_{{\rm{h}}}\lt {10}^{13}{h}^{-1}{M}_{\odot }$ . The H I mass in halos more massive than ${10}^{13}{h}^{-1}{M}_{\odot }$ generally grows by mergers, with the dependence on halo richness becoming much weaker.
Star-forming galaxies with strong nebular and collisional emission lines are privileged target galaxies in forthcoming cosmological large galaxy redshift surveys. We use the COSMOS2015 photometric catalogue to model galaxy spectral energy distributions and emission-line fluxes. We adopt an empirical but physically motivated model that uses information from the best-fitting spectral energy distribution of stellar continuum to each galaxy. The emission-line flux model is calibrated and validated against direct flux measurements in subsets of galaxies that have 3D-HST or zCOSMOS-Bright spectra. We take a particular care in modelling dust attenuation such that our model can explain both Hα and [O II] observed fluxes at different redshifts. We find that a simple solution to this is to introduce a redshift evolution in the dust attenuation fraction parameter, f = Estar(B - V)/Egas(B - V), as f(z) = 0.44 + 0.2z. From this catalogue, we derive the Hα and [O II] luminosity functions up to redshifts of about 2.5 after carefully accounting for emission line flux and redshift errors. This allows us to make predictions for Hα and [O II] galaxy number counts in next-generation cosmological redshift surveys. Our modelled emission lines and spectra in the COSMOS2015 catalogue shall be useful to study the target selection for planned next-generation galaxy redshift surveys and we make them publicly available as 'EL-COSMOS' on the ASPIC data base.
Comparison of theoretical line profiles to observations provides important tests for supernova explosion models. We study the shapes of radioactive decay lines predicted by current 3D core-collapse explosion simulations, and compare these to observations of SN 1987A and Cas A. Both the widths and shifts of decay lines vary by several thousand kilometres per second depending on viewing angle. The line profiles can be complex with multiple peaks. By combining observational constraints from 56Co decay lines, 44Ti decay lines, and Fe IR lines, we delineate a picture of the morphology of the explosive burning ashes in SN 1987A. For MZAMS = 15-20 M⊙ progenitors exploding with ∼1.5 × 1051 erg, ejecta structures suitable to reproduce the observations involve a bulk asymmetry of the 56Ni of at least ∼400 km s-1 and a bulk velocity of at least 1500 km s-1. By adding constraints to reproduce the UVOIR bolometric light curve of SN 1987A up to 600 d, an ejecta mass around 14 M⊙ is favoured. We also investigate whether observed decay lines can constrain the neutron star (NS) kick velocity. The model grid provides a constraint VNS > Vredshift, and applying this to SN 1987A gives a NS kick of at least 500 km s-1. For Cas A, our single model provides a satisfactory fit to the NuSTAR observations and reinforces the result that current neutrino-driven core-collapse SN models achieve enough bulk asymmetry in the explosive burning material. Finally, we investigate the internal gamma-ray field and energy deposition, and compare the 3D models to 1D approximations.
We present stellar metallicity measurements of more than 600 late-type stars in the central 10 pc of the Galactic centre. Together with our previously published KMOS data, this data set allows us to investigate, for the first time, spatial variations of the nuclear star cluster's metallicity distribution. Using the integral-field spectrograph KMOS (VLT) we observed almost half of the area enclosed by the nuclear star cluster's effective radius. We extract spectra at medium spectral resolution, and apply full spectral fitting utilising the PHOENIX library of synthetic stellar spectra. The stellar metallicities range from [M/H]=-1.25 dex to [M/H]> +0.3 dex, with most of the stars having super-solar metallicity. We are able to measure an anisotropy of the stellar metallicity distribution. In the Galactic North, the portion of sub-solar metallicity stars with [M/H]<0.0 dex is more than twice as high as in the Galactic South. One possible explanation for different fractions of sub-solar metallicity stars in different parts of the cluster is a recent merger event. We propose to test this hypothesis with high-resolution spectroscopy, and by combining the metallicity information with kinematic data.
Ultralight bosonic fields are compelling dark-matter candidates and arise in a variety of beyond standard model scenarios. These fields can tap energy and angular momentum from spinning black holes through superradiant instabilities, during which a macroscopic bosonic condensate develops around the black hole. Striking features of this phenomenon include gaps in the spin-mass distribution of astrophysical black holes and a continuous gravitational-wave (GW) signal emitted by the condensate. So far these processes have been studied in great detail for scalar fields and, more recently, for vector fields. Here we take an important step forward in the black hole superradiance program by computing, analytically, the instability timescale, direct GW emission, and stochastic background, in the case of massive tensor (i.e., spin-2) fields. Our analysis is valid for any black hole spin and for small boson masses. The instability of massive spin-2 fields shares some properties with the scalar and vector cases, but its phenomenology is much richer, for example, there exist multiple modes with comparable instability timescales, and the dominant GW signal is hexadecapolar rather than quadrupolar. Electromagnetic and GW observations of spinning black holes in the mass range M ∈(1 ,1010) M⊙ can constrain the mass of a putative spin-2 field in the range 10-22≲mb c2/eV ≲10-10 . For 10-17≲mb c2/eV ≲10-15 , the space mission LISA could detect the continuous GW signal for sources at redshift z =20 , or even larger.
The chemical composition of planets is determined by the distribution of the various molecular species in the protoplanetary disk at the time of their formation. To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outflow sources in Taurus, we report on new ALMA Band 6 (~1.3 mm) observations with ~0.15'' (20 au) resolution toward the embedded young star DG Tau B. Images of the continuum emission reveals a dust disk with rings and, putatively, a leading spiral arm. The disk, as well as the prominent outflow cavities, are detected in CO, H2CO, CS, and CN; instead, they remain undetected in SO2, HDO, and CH3OH. From the absorption of the back-side outflow, we inferred that the disk emission is optically thick in the inner 50 au. This morphology explains why no line emission is detected from this inner region and poses some limitations toward the calculation of the dust mass and the characterization of the inner gaseous disk. The H2CO and CS emission from the inner 200 au is mostly from the disk, and their morphology is very similar. The CN emission significantly differs from the other two molecules as it is observed only beyond 150 au. This ring-like morphology is consistent with previous observations and the predictions of thermochemical disk models. Finally, we constrained the disk-integrated column density of all molecules. In particular, we found that the CH3OH/H2CO ratio must be smaller than ~2, making the methanol non-detection still consistent with the only such ratio available from the literature (1.27 in TW Hya).
The reduced datacubes are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/636/A65
Following the recent analysis done in collaboration with Jason Aebischer and Christoph Bobeth, I summarize the optimal, in our view, strategy for the present evaluation of the ratio ɛ ‧/ɛ in the Standard Model. In particular, I emphasize the importance of the correct matching of the long-distance and short-distance contributions to ɛ ‧/ɛ, which presently is only achieved by RBC-UKQCD lattice QCD collaboration and by the analytical Dual QCD approach. An important role play also the isospin-breaking and QED effects, which presently are best known from chiral perturbation theory, albeit still with a significant error. Finally, it is essential to include NNLO QCD corrections in order to reduce unphysical renormalization scheme and scale dependences present at the NLO level. Here µ c in m c (µ c ) in the case of QCD penguin contributions and µ t in m t (µ t ) in the case of electroweak penguin contributions play the most important roles. Presently the error on ɛ ‧/ɛ is dominated by the uncertainties in the QCDP parameter B_6(1/2) and the isospin-breaking parameter \hat Ω {{eff}}. We present a table illustrating this.
We investigate the stellar kinematics of a sample of galaxies extracted from the hydrodynamic cosmological Magneticum Pathfinder simulations out to five half-mass radii. We construct differential radial stellar spin profiles quantified by the observationally widely used λ and the closely related (V/σ) parameters. We find three characteristic profile shapes: profiles exhibiting a (I) peak within 2.5 half-mass radii and a subsequent decrease; (II) continuous increase that plateaus at larger radii typically with a high amplitude; (III) completely flat behaviour typically with low amplitude, in agreement with observations. This shows that the kinematic state of the stellar component can vary significantly with radius, suggesting a distinct interplay between in-situ star formation and ex-situ accretion of stars. Following the evolution of our sample through time, we provide evidence that the accretion history of galaxies with decreasing profiles is dominated by the anisotropic accretion of low-mass satellites that get disrupted beyond ∼2.0 half-mass radii, building up a stellar halo with non-ordered motion while maintaining the central rotation already present at z = 2. In fact, at z = 2 decreasing profiles are the predominant profile class. Hence, we can predict a distinct formation pathway for galaxies with a decreasing profile and show that the centre resembles an old embedded disc. Furthermore, we show that the radius of the kinematic transition provides a good estimation for the transition radius from in-situ stars in the centre to accreted stars in the halo.
If dark matter was produced in the early Universe by the decoupling of its annihilations into known particles, there is a sharp experimental target for the size of its coupling. We show that if dark matter was produced by inelastic scattering against a lighter particle from the thermal bath, then its coupling can be exponentially smaller than the coupling required for its production from annihilations. As an application, we demonstrate that dark matter produced by inelastic scattering against electrons provides new thermal relic targets for direct detection and fixed target experiments.
The baryon acoustic oscillations feature (BAO) imprinted in the clustering correlation function is known to furnish us cosmic distance determinations that are independent of the cosmological-background model and the primordial perturbation parameters. These measurements can be accomplished rigorously by means of the purely geometric BAO methods. To date two different purely geometric BAO approaches have been proposed. The first exploits the linear-point standard ruler. The second, called correlation-function model-fitting, exploits the sound-horizon standard ruler. A key difference between them is that, when estimated from clustering data, the linear point makes use of a cosmological-model-independent procedure to extract the ratio of the ruler to the cosmic distance, while the correlation-function model-fitting relies on a phenomenological cosmological model for the correlation function. Nevertheless the two rulers need to be precisely defined independently of any specific observable (e.g., the BAO). We define the linear point and sound horizon and we fully characterize and compare the two rulers' cosmological-parameter dependence. We find that they are both geometrical (i.e., independent of the primordial cosmological parameters) within the required accuracy, and that they have the same parameter dependence for a wide range of parameter values. We estimate the rulers' best-fit values and errors, given the cosmological constraints obtained by the Planck Satellite team from their measurements of the cosmic microwave background temperature and polarization anisotropies. We do this for three different cosmological models encompassed by the purely geometric BAO methods. In each case we find that the relative errors of the two rulers coincide and they are insensitive to the assumed cosmological model. Interestingly both the linear point and the sound horizon shift by 0.5 σ when we do not fix the spatial geometry to be flat in Λ CDM . This points toward a sensitivity of the rulers to different cosmological models when they are estimated from the cosmic microwave background.
The quality of the recent GlueX J /ψ photoproduction data from Hall D at Jefferson Laboratory and the proximity of the data to the energy threshold, gives access to a variety of interesting physics aspects. As an example, an estimation of the J /ψ -nucleon scattering length αJ /ψ p is provided within the vector meson dominance model. It results in | αJ /ψ p|=(3.08 ±0.55 (stat . ) ±0.42 (syst . ) ) mfm which is much smaller than a typical size of a hadron.
Building on Weinberg's approach to effective field theory for inflation, we construct an effective Lagrangian for a pseudo scalar (axion) inflaton field with shift symmetry. In this Lagrangian we allow the axion field to couple to non-Abelian gauge fields via a Chern-Simons term. We then analyze a class of inflation models driven by kinetic terms. We find that the observational constraints on the amplitudes of curvature perturbations and non-Gaussianity yield a lower bound for the tensor-to-scalar ratio of $r\gtrsim 5\times 10^{-3}$ from the vacuum fluctuation. The sourced gravitational wave from SU(2) gauge fields further increases the tensor-to-scalar ratio and makes the total gravitational wave partially chiral and non-Gaussian, which can be probed by polarization of the cosmic microwave background and direct detection experiments. We discuss constraints on parameter space due to backreaction of spin-2 particles produced by the gauge field.
We have studied the small-scale distribution of atomic hydrogen (H I) using 21 cm absorption spectra against multiple-component background radio continuum sources from the 21-SPONGE survey and the Millennium Arecibo Absorption-Line Survey. We have found >5σ optical depth variations at a level of ∼0.03-0.5 between 13 out of 14 adjacent sightlines separated by a few arcseconds to a few arcminutes, suggesting the presence of neutral structures on spatial scales from a few to thousands of au (which we refer to as tiny-scale atomic structure, TSAS). The optical depth variations are strongest in directions where the H I column density and the fraction of H I in the cold neutral medium (CNM) are highest, which tend to be at low Galactic latitudes. By measuring changes in the properties of Gaussian components fitted to the absorption spectra, we find that changes in both the peak optical depth and the linewidth of TSAS absorption features contribute to the observed optical depth variations, while changes in the central velocity do not appear to strongly impact the observed variations. Both thermal and turbulent motions contribute appreciably to the linewidths, but the turbulence does not appear strong enough to confine overpressured TSAS. In a majority of cases, the TSAS column densities are sufficiently high that these structures can radiatively cool fast enough to maintain thermal equilibrium with their surroundings, even if they are overpressured. We also find that a majority of TSAS is associated with the CNM. For TSAS in the direction of the Taurus molecular cloud and the local Leo cold cloud, we estimate densities over an order of magnitude higher than typical CNM densities.
We examine the contribution of small instantons to the axion mass in various UV completions of QCD. We show that the reason behind the potential dominance of such contributions is the non-trivial embedding of QCD into the UV theory. The effects from instantons in the partially broken gauge group appear as "fractional instanton" corrections in the effective theory. These will exhibit unusual dependences on the various scales in the problem whenever the index of embedding is non-trivial. We present a full one-instanton calculation of the axion mass in the simplest product group models, carefully keeping track of numerical prefactors. Rather than using a 't Hooft operator approximation we directly evaluate the contributions to the vacuum bubble, automatically capturing the effects of closing up external fermion lines with Higgs loops. This approach is manifestly finite and removes the uncertainty associated with introducing a cutoff scale for the Higgs loops. We verify that the small instantons may dominate over the QCD contribution for very high breaking scales and at least three group factors.
Polarizations of primordial gravitational waves can be relevant when considering inflationary universe in modified gravity or when matter fields survive during inflation. Such polarizations have been discussed in the Bunch-Davies vacuum. Instead of taking into account dynamical generation of polarizations of gravitational waves, in this paper, we consider polarized initial states constructed from $SU(2)$ coherent states. We then evaluate the power spectrums of the primordial gravitational waves in the states.
New Physics can manifest itself in kinematic distributions of particle decays. The parameter space defining the shape of such distributions can be large which is chalenging for both theoretical and experimental studies. Using clustering algorithms, the parameter space can however be dissected into subsets (clusters) which correspond to similar kinematic distributions. Clusters can then be represented by benchmark points, which allow for less involved studies and a concise presentation of the results. We demonstrate this concept using the Python package ClusterKinG, an easy to use framework for the clustering of distributions that particularly aims to make these techniques more accessible in a High Energy Physics context. As an example we consider B ¯→D(∗)τ-ν¯τ distributions and discuss various clustering methods and possible implications for future experimental analyses.
We study the Schrödinger-Poisson (SP) method in the context of cosmological large-scale structure formation in an expanding background. In the limit ℏ→0, the SP technique can be viewed as an effective method to sample the phase space distribution of cold dark matter that remains valid on non-linear scales. We present results for the 2D and 3D matter correlation function and power spectrum at length scales corresponding to the baryon acoustic oscillation (BAO) peak. We discuss systematic effects of the SP method applied to cold dark matter and explore how they depend on the simulation parameters. In particular, we identify a combination of simulation parameters that controls the scale-independent loss of power observed at low redshifts, and discuss the scale relevant to this effect.
In this work, we study how the dust coagulation/fragmentation will influence the evolution and observational appearances of vortices induced by a massive planet embedded in a low-viscosity disk by performing global 2D high-resolution hydrodynamical simulations. Within the vortex, due to its higher gas surface density and steeper pressure gradients, dust coagulation, fragmentation, and drift (to the vortex center) are all quite efficient, producing dust particles ranging from 1 μm to ∼1.0 cm, as well as an overall high dust-to-gas ratio (above unity). In addition, the dust size distribution is quite nonuniform inside the vortex, with the mass-weighted average dust size at the vortex center (∼4.0 mm) being a factor of ∼10 larger than other vortex regions. Both large (∼millimeter) and small (tens of microns) particles contribute strongly to affect the gas motion within the vortex. As such, we find that the inclusion of dust coagulation has a significant impact on the vortex lifetime and the typical vortex lifetime is about 1000 orbits. After the initial gaseous vortex is destroyed, the dust spreads into a ring with a few remaining smaller gaseous vortices with a high dust concentration and a large maximum size (∼millimeter). At late time, the synthetic dust continuum images for the coagulation case show as a ring inlaid with several hot spots at the 1.33 mm band, while only distinct hot spots remain at 7.0 mm.
We carry out a comprehensive analysis of the full set of B¯q→D(∗)q form factors for spectator quarks q=u,d,s within the framework of the Heavy-Quark Expansion (HQE) to order O(αs,1/mb,1/m2c). In addition to the available lattice QCD calculations we make use of two new sets of theoretical constraints: we produce for the first time numerical predictions for the full set of B¯s→D(∗)s form factors using Light-Cone Sum Rules with Bs-meson distribution amplitudes. Furthermore, we reassess the QCD three-point sum rule results for the Isgur-Wise functions entering all our form factors for both q=u,d and q=s spectator quarks. These additional constraints allow us to go beyond the commonly used assumption of SU(3)F symmetry for the B¯s→D(∗)s form factors, especially in the unitarity constraints which we impose throughout our analysis. We find the coefficients of the IW functions emerging at O(1/m2c) to be consistent with the naive O(1) expectation, indicating a good convergence of the HQE. While we do not find significant SU(3) breaking, the explicit treatment of q=s as compared to a simple symmetry assumption renders the unitarity constraints more effective. We find that the (pseudo)scalar bounds are saturated to a large degree, which affects our theory predictions. We analyze the phenomenological consequences of our improved form factors by extracting |Vcb| from B¯→D(∗)ℓν decays and producing theoretical predictions for the lepton-flavour universality ratios R(D), R(D∗), R(Ds) and R(D∗s), as well as the τ- and D∗q polarization fractions for the B¯q→D(∗)qτν modes.
Context. Complex organic molecules (COMs) have been detected in a few Class 0 protostars but their origin is not well understood. While the usual picture of a hot corino explains their presence as resulting from the heating of the inner envelope by the nascent protostar, shocks in the outflow, disk wind, the presence of a flared disk, or the interaction region between envelope and disk at the centrifugal barrier have also been claimed to enhance the abundance of COMs.
Aims: Going beyond studies of individual objects, we want to investigate the origin of COMs in young protostars on a statistical basis.
Methods: We use the CALYPSO survey performed with the Plateau de Bure Interferometer of the Institut de Radioastronomie Millimétrique to search for COMs at high angular resolution in a sample of 26 solar-type protostars, including 22 Class 0 and four Class I objects. We derive the column densities of the detected molecules under the local thermodynamic equilibrium approximation and search for correlations between their abundances and with various source properties.
Results: Methanol is detected in 12 sources and tentatively in one source, which represents half of the sample. Eight sources (30%) have detections of at least three COMs. We find a strong chemical differentiation in multiple systems with five systems having one component with at least three COMs detected but the other component devoid of COM emission. All sources with a luminosity higher than 4 L⊙ have at least one detected COM whereas no COM emission is detected in sources with internal luminosity lower than 2 L⊙, likely because of a lack of sensitivity. Internal luminosity is found to be the source parameter impacting the COM chemical composition of the sources the most, while there is no obvious correlation between the detection of COM emission and that of a disk-like structure. A canonical hot-corino origin may explain the COM emission in four sources, an accretion-shock origin in two or possibly three sources, and an outflow origin in three sources. The CALYPSO sources with COM detections can be classified into three groups on the basis of the abundances of oxygen-bearing molecules, cyanides, and CHO-bearing molecules. These chemical groups correlate neither with the COM origin scenarios, nor with the evolutionary status of the sources if we take the ratio of envelope mass to internal luminosity as an evolutionary tracer. We find strong correlations between molecules that are a priori not related chemically (for instance methanol and methyl cyanide), implying that the existence of a correlation does not imply a chemical link.
Conclusions: The CALYPSO survey has revealed a chemical differentiation in multiple systems that is markedly different from the case of the prototypical binary IRAS 16293-2422. This raises the question of whether all low-mass protostars go through a phase showing COM emission. A larger sample of young protostars and a more accurate determination of their internal luminosity will be necessary to make further progress. Searching for correlations between the COM emission and the jet/outflow properties of the sources may also be promising.
Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).
The CALYPSO calibrated visibility tables and maps are publicly available at http://www.iram-institute.org/EN/content-page-317-7-158-240-317-0.html
We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-sized planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts to being transparent to the planet flux in the infrared (IR). Column densities are estimated by means of three-dimensional hydrodynamical models, performed for several planet masses. Expected magnitudes are obtained by using typical extinction properties of the disc material and evolutionary models of giant planets. For the simulated cases located at 5.2 au in a disc with a local unperturbed surface density of 127 g cm^{-2}, a 1MJ planet is highly extinct in the J, H, and Kbands, with predicted absolute magnitudes ≥ 50 mag. In the L and Mbands, extinction decreases, with planet magnitudes between 25 and 35 mag. In the Nband, due to the silicate feature on the dust opacities, the expected magnitude increases to ∼40 mag. For a 2MJ planet, the magnitudes in the J, H, and Kbands are above 22 mag, while for the L, M, and Nbands, the planet magnitudes are between 15 and 20 mag. For the 5MJ planet, extinction does not play a role in any IR band, due to its ability to open deep gaps. Contrast curves are derived for the transition discs in CQ Tau, PDS 70, HL Tau, TW Hya, and HD 163296. Planet mass upper limits are estimated for the known gaps in the last two systems.
We present the novel algorithmically regularized integration method MSTAR for high-accuracy (|ΔE/E| ≳ 10-14) integrations of N-body systems using minimum spanning tree coordinates. The twofold parallelization of the O(N_part^2) force loops and the substep divisions of the extrapolation method allow for a parallel scaling up to NCPU = 0.2 × Npart. The efficient parallel scaling of MSTAR makes the accurate integration of much larger particle numbers possible compared to the traditional algorithmic regularization chain (AR-CHAIN) methods, e.g. Npart = 5000 particles on 400 CPUs for 1 Gyr in a few weeks of wall-clock time. We present applications of MSTAR on few particle systems, studying the Kozai mechanism and N-body systems like star clusters with up to Npart = 104 particles. Combined with a tree or fast multipole-based integrator, the high performance of MSTAR removes a major computational bottleneck in simulations with regularized subsystems. It will enable the next-generation galactic-scale simulations with up to 109 stellar particles (e.g. m_\star = 100 M_⊙ for an M_\star = 10^{11} M_⊙ galaxy), including accurate collisional dynamics in the vicinity of nuclear supermassive black holes.
We present a statistical analysis of the optical properties of an X-ray-selected Type 1 active galactic nucleus (AGN) sample, using high signal-to-noise ratio (S/N>20) spectra of the counterparts of the ROSAT/2RXS sources in the footprint of the SDSS-IV/SPIDERS (Spectroscopic IDentification of eROSITA Sources) programme. The final sample contains 2100 sources. It significantly extends the redshift and luminosity ranges (z ∼ 0.01-0.80 and L_{0.1-2.4 keV} ∼ 2.0 × 10^{41}-1.0 × 10^{46} erg s^{-1}) used so far in this kind of analysis. By means of a principal component analysis, we derive eigenvector (EV) 1 and 2 in an eleven-dimensional optical and X-ray parameter space, which are consistent with previous results. The validity of the correlations of the Eddington ratio L/LEdd with EV1 and the black hole mass with EV2 is strongly confirmed. These results imply that L/LEdd and black hole mass are related to the diversity of the optical properties of Type 1 AGNs. Investigating the relation of the width and asymmetry of H β and the relative strength of the iron emission r_{Fe II}, we show that our analysis supports the presence of a distinct kinematic region: the very broad line region. Furthermore, comparing sources with a red-asymmetric broad H β emission line to sources for which it is blue asymmetric, we find an intriguing difference in the correlation of the Fe II and the continuum emission strengths. We show that this contrasting behaviour is consistent with a flattened, stratified model of the broad-line region, in which the Fe II-emitting region is shielded from the central source.
The inner parsec of our Galaxy contains tens of Wolf-Rayet stars whose powerful outflows are constantly interacting while filling the region with hot, diffuse plasma. Theoretical models have shown that, in some cases, the collision of stellar winds can generate cold, dense material in the form of clumps. However, their formation process and properties are not well understood yet. In this work, we present, for the first time, a statistical study of the clump formation process in unstable wind collisions. We study systems with dense outflows (∼ 10^{-5} M_{⊙ } yr^{-1}), wind speeds of 500-1500 km s^{-1}, and stellar separations of ∼20-200 au. We develop three-dimensional high-resolution hydrodynamical simulations of stellar wind collisions with the adaptive-mesh refinement grid-based code RAMSES. We aim at characterizing the initial properties of clumps that form through hydrodynamic instabilities, mostly via the non-linear thin-shell instability (NTSI). Our results confirm that more massive clumps are formed in systems whose winds are close to the transition between the radiative and adiabatic regimes. Increasing either the wind speed or the degree of asymmetry increases the dispersion of the clump mass and ejection speed distributions. Nevertheless, the most massive clumps are very light (∼10-3-10^{-2} M_{\oplus }), about three orders of magnitude less massive than theoretical upper limits. Applying these results to the Galactic Centre, we find that clumps formed through the NTSI should not be heavy enough either to affect the thermodynamic state of the region or to survive for long enough to fall on to the central supermassive black hole.
It has been speculated for a long time that neutrinos from a supernova (SN) may undergo fast flavor conversions near the collapsed stellar core. We perform a detailed study of this intriguing possibility, for the first time analyzing two time-dependent state-of-the-art three-dimensional (3D) SN models of 9 M⊙ and 20 M⊙ from recent papers of Glas et al. Both models were computed with multidimensional three-flavor neutrino transport based on a two-moment solver, and both exhibit the presence of the so-called lepton-number emission self-sustained asymmetry (LESA). The transport solution does not provide the angular distributions of the flavor-dependent neutrino fluxes, which are crucial to track the fast flavor instability. To overcome this limitation, we use a recently proposed approach based on the angular moments of the energy-integrated electron lepton-number distribution up to second order, i.e., angle-energy integrals of the difference between νe and ν¯e phase-space distributions multiplied by corresponding powers of the unit vector of the neutrino velocity. With this method we find the possibility of fast neutrino flavor instability at radii smaller than ∼20 km , which is well interior to the neutrinosphere where neutrinos are still in the diffusive and near-equilibrium regime. Our results confirm recent observations in a two-dimensional (2D) (axisymmetric) SN model and in 2D and 3D models with a fixed matter background, which were computed with Boltzmann neutrino transport. However, the flavor unstable locations are not isolated points as discussed previously, but thin skins surrounding volumes where ν¯e are more abundant than νe. These volumes grow with time and appear first in the convective layer of the proto-neutron star (PNS), where a decreasing electron fraction and high temperatures favor the occurrence of regions with negative neutrino chemical potential. Since the electron fraction remains higher in the LESA dipole direction, where convective lepton-number transport out from the nonconvective PNS core slows down the deleptonization, flavor unstable conditions become more widespread in the opposite hemisphere. This interesting phenomenon deserves further investigation, since its impact on SN modeling and possible consequences for SN dynamics and neutrino observations are presently unclear.
We construct an emulator for the halo mass function over group and cluster mass scales for a range of cosmologies, including the effects of dynamical dark energy and massive neutrinos. The emulator is based on the recently completed Mira-Titan Universe suite of cosmological N-body simulations. The main set of simulations spans 111 cosmological models with 2.1 Gpc boxes. We extract halo catalogs in the redshift range z = [0.0, 2.0] and for masses . The emulator covers an eight-dimensional hypercube spanned by {, , , σ 8, h, n s , w 0, w a }; spatial flatness is assumed. We obtain smooth halo mass functions by fitting piecewise second-order polynomials to the halo catalogs and employ Gaussian process regression to construct the emulator while keeping track of the statistical noise in the input halo catalogs and uncertainties in the regression process. For redshifts z ≲ 1, the typical emulator precision is better than 2% for and <10% for . For comparison, fitting functions using the traditional universal form for the halo mass function can be biased at up to 30% at for z = 0. Our emulator is publicly available at github.com/SebastianBocquet/MiraTitanHMFemulator.
Bimetric theory describes a massless and a massive spin-2 field with fully non-linear (self-)interactions. It has a rich phenomenology and has been successfully tested with several data sets. However, the observational constraints have not been combined in a consistent framework, yet. We propose a parametrization of bimetric solutions in terms of the effective cosmological constant Λ and the mass mFP of the spin-2 field as well as its coupling strength to ordinary matter &baralpha;. This simplifies choosing priors in statistical analysis and allows to directly constrain these parameters with observational data not only from local systems but also from cosmology. By identifying the physical vacuum of bimetric theory these parameters are uniquely determined. We work out the new parametrization for various submodels and present the implied consistency constraints on the physical parameter space. As an application we derive observational constraints from SN1a on the physical parameters. We find that a large portion of the physical parameter space is in perfect agreement with current supernova data including self-accelerating models with a heavy spin-2 field.
Type Ic supernovae (SNe Ic) are a sub-class of core-collapse SNe that exhibit no helium or hydrogen lines in their spectra. Their progenitors are thought to be bare carbon-oxygen cores formed during the evolution of massive stars that are stripped of their hydrogen and helium envelopes sometime before collapse. SNe Ic present a range of luminosities and spectral properties, from luminous GRB-SNe with broad-lined spectra to less luminous events with narrow-line spectra. Modelling SNe Ic reveals a wide range of both kinetic energies, ejecta masses, and 56Ni masses. To explore this diversity and how it comes about, light curves and spectra are computed from the ejecta following the explosion of an initially 22 M⊙ progenitor that was artificially stripped of its hydrogen and helium shells, producing a bare CO core of ∼5 M⊙, resulting in an ejected mass of ∼4 M⊙, which is an average value for SNe Ic. Four different explosion energies are used that cover a range of observed SNe. Finally, 56Ni and other elements are artificially mixed in the ejecta using two approximations to determine how element distribution affects light curves and spectra. The combination of different explosion energy and degree of mixing produces spectra that roughly replicate the distribution of near-peak spectroscopic features of SNe Ic. High explosion energies combined with extensive mixing can produce red, broad-lined spectra, while minimal mixing and a lower explosion energy produce bluer, narrow-lined spectra.
We consider a scenario where the dark sector includes two Feebly Interacting Massive Particles (FIMPs), with couplings to the Standard Model particles that allow their production in the Early Universe via thermal freeze-in. These couplings generically lead to the decay of the heavier dark matter component into the lighter, possibly leading to observable signals of the otherwise elusive FIMPs. Concretely, we argue that the loop induced decay ψ2→ψ1γ for fermionic FIMPs, or phi2→phi1γγ for scalar FIMPs, could have detectable rates for model parameters compatible with the observed dark matter abundance.
All life on Earth is built of organic molecules, so the primordial sources of reduced carbon remain a major open question in studies of the origin of life. A variant of the alkaline-hydrothermal-vent theory for life’s emergence suggests that organics could have been produced by the reduction of CO2 via H2 oxidation, facilitated by geologically sustained pH gradients. The process would be an abiotic analog—and proposed evolutionary predecessor—of the Wood–Ljungdahl acetyl-CoA pathway of modern archaea and bacteria. The first energetic bottleneck of the pathway involves the endergonic reduction of CO2 with H2 to formate (HCOO–), which has proven elusive in mild abiotic settings. Here we show the reduction of CO2 with H2 at room temperature under moderate pressures (1.5 bar), driven by microfluidic pH gradients across inorganic Fe(Ni)S precipitates. Isotopic labeling with 13C confirmed formate production. Separately, deuterium (2H) labeling indicated that electron transfer to CO2 does not occur via direct hydrogenation with H2 but instead, freshly deposited Fe(Ni)S precipitates appear to facilitate electron transfer in an electrochemical-cell mechanism with two distinct half-reactions. Decreasing the pH gradient significantly, removing H2, or eliminating the precipitate yielded no detectable product. Our work demonstrates the feasibility of spatially separated yet electrically coupled geochemical reactions as drivers of otherwise endergonic processes. Beyond corroborating the ability of early-Earth alkaline hydrothermal systems to couple carbon reduction to hydrogen oxidation through biologically relevant mechanisms, these results may also be of significance for industrial and environmental applications, where other redox reactions could be facilitated using similarly mild approaches.
Context. The water snow line divides dry and icy solid material in protoplanetary disks. It has been thought to significantly affect planet formation at all stages. If dry particles break up more easily than icy ones, then the snow line causes a traffic jam because small grains drift inward at lower speeds than larger pebbles.
Aims: We aim to evaluate the effect of high dust concentrations around the snow line onto the gas dynamics.
Methods: Using numerical simulations, we modeled the global radial evolution of an axisymmetric protoplanetary disk. Our model includes particle growth, the evaporation and recondensation of water, and the back-reaction of dust onto the gas. The model takes into account the vertical distribution of dust particles.
Results: We find that the dust back-reaction can stop and even reverse the net flux of gas outside the snow line, decreasing the gas accretion rate onto the star to under 50% of its initial value. At the same time, the dust accumulates at the snow line, reaching dust-to-gas ratios of ɛ ≳ 0.8, and it delivers large amounts of water vapor towards the inner disk as the icy particles cross the snowline. However, the accumulation of dust at the snow line and the decrease in the gas accretion rate only take place if the global dust-to-gas ratio is high (ɛ0 ≳ 0.03), the viscous turbulence is low (αν ≲ 10-3), the disk is large enough (rc ≳ 100 au), and only during the early phases of the disk evolution (t ≲ 1 Myr). Otherwise the dust back-reaction fails to perturb the gas motion.
We study radial oscillations of non-rotating neutron stars (NSs) in four-dimensional general relativity. The interior of the NS was modeled within a recently proposed multicomponent realistic equation of state (EoS) with the induced surface tension (IST). In particular, we considered the IST EoS with two sets of model parameters, that both reproduce all the known properties of normal nuclear matter, give a high quality description of the proton flow constraint, hadron multiplicities created in nuclear-nuclear collisions, consistent with astrophysical observations and the observational data from the NS-NS merger. We computed the 12 lowest radial oscillation modes, their frequencies and corresponding eigenfunctions, as well as the large frequency separation for six selected fiducial NSs (with different radii and masses of 1.2, 1.5 and 1.9 solar masses) of the two distinct model sets. The calculated frequencies show their continuous growth with an increase of the NS central baryon density. Moreover, we found correlations between the behavior of the first eigenfunction calculated for the fundamental mode, the adiabatic index and the speed of sound profile, which could be used to probe the internal structure of NSs with the asteroseismology data.
We combine the NLTE spectral analysis of the detached O-type eclipsing binary OGLE-LMC-ECL-06782 with the analysis of the radial velocity curve and light curve to measure an independent distance to the Large Magellanic Cloud (LMC). In our spectral analysis we study composite spectra of the system at quadrature and use the information from radial velocity and light curve about stellar gravities, radii, and component flux ratio to derive effective temperature, reddening, extinction, and intrinsic surface brightness. We obtain a distance modulus to the LMC of m - M = 18.53 ± 0.04 mag. This value is 0.05 mag larger than the precision distance obtained recently from the analysis of a large sample of detached, long period late spectral type eclipsing binaries but agrees within the margin of the uncertainties. We also determine the surface brightnesses of the system components and find good agreement with the published surface brightness-color relationship. A comparison of the observed stellar parameters with the prediction of stellar evolution based on the MESA stellar evolution code shows reasonable agreement, but requires a reduction of the internal angular momentum transport to match the observed rotational velocities.
Origins of contemporary $B$-physics. Mesons with beauty and charm. Stable tetraquarks? Flavor and the problem of identity. Top matters. Electroweak symmetry breaking and the Higgs sector. Future instruments.
The simultaneous study of top-down and bottom-up approaches to modular flavor symmetry leads necessarily to the concept of eclectic flavor groups. These are non-trivial products of modular and traditional flavor symmetries that exhibit the phenomenon of local flavor enhancement in moduli space. We develop methods to determine the eclectic flavor groups that can be consistently associated with a given traditional flavor symmetry. Applying these methods to a large family of prominent traditional flavor symmetries, we try to identify potential candidates for realistic eclectic flavor groups and show that they are relatively rare. Model building with finite modular flavor symmetries thus appears to be much more restrictive than previously thought.
We show that for a wide range of stellar masses, from 0.3 to 20 M⊙, and for evolutionary phases from the main sequence to the beginning of the red giant stage, the stellar flux-weighted gravity, gF ≅ g/ ${T}_{\mathrm{eff}}^{4}$ , is tightly correlated with absolute bolometric magnitude ${M}_{\mathrm{bol}}$ . Such a correlation is predicted by stellar evolution theory. We confirm this relation observationally, using a sample of 445 stars with precise stellar parameters. It holds over 17 stellar magnitudes from ${M}_{\mathrm{bol}}$ = 9.0 to -8.0 mag with a scatter of 0.17 mag above ${M}_{\mathrm{bol}}$ = -3.0 and 0.29 mag below this value. We then test the relation with 2.2 million stars with 6.5 mag ≥ ${M}_{\mathrm{bol}}$ ≥ 0.5 mag, where "mass-produced" but robust $\mathrm{log}\,g$ , ${T}_{{\rm{e}}{\rm{f}}{\rm{f}}},$ and ${M}_{\mathrm{bol}}$ from LAMOST DR5 and Gaia DR2 are available. We find that the same relation holds with a scatter of ∼0.2 mag for single stars offering a simple spectroscopic distance estimate good to ∼10%.
We present a 7 minute long 4π-3D simulation of a shell merger event in a nonrotating 18.88 ${M}_{\odot }$ M ⊙ supernova progenitor before the onset of gravitational collapse. The key motivation is to capture the large-scale mixing and asymmetries in the wake of the shell merger before collapse using a self-consistent approach. The 4π geometry is crucial, as it allows us to follow the growth and evolution of convective modes on the largest possible scales. We find significant differences between the kinematic, thermodynamic, and chemical evolution of the 3D and 1D models. The 3D model shows vigorous convection leading to more efficient mixing of nuclear species. In the 3D case, the entire oxygen shell attains convective Mach numbers of ≈0.1, whereas in the 1D model, the convective velocities are much lower, and there is negligible overshooting across convective boundaries. In the 3D case, the convective eddies entrain nuclear species from the neon (and carbon) layers into the deeper part of the oxygen-burning shell, where they burn and power a violent convection phase with outflows. This is a prototypical model of a convective-reactive system. Due to the strong convection and resulting efficient mixing, the interface between the neon layer and the silicon-enriched oxygen layer disappears during the evolution, and silicon is mixed far out into the merged oxygen/neon shell. Neon entrained inward by convective downdrafts burns, resulting in lower neon mass in the 3D model compared to the 1D model at the time of collapse. In addition, the 3D model develops remarkable large-scale, large-amplitude asymmetries, which may have important implications for the impending gravitational collapse and subsequent explosion.
We consider scenarios with a heavy Z' gauge boson with flavour non-universal quark and lepton couplings with the goal to illustrate how the cancellation of gauge anomalies generated by the presence of an additional U(1)' gauge symmetry would imply correlations between FCNC processes within the quark sector, within the lepton sector and most interestingly between quark flavour and lepton flavour violating processes. To this end we present simple scenarios with only left-handed flavour-violating Z' couplings and those in which also right-handed flavour-violating couplings are present. The considered scenarios are characterized by a small number of free parameters but in contrast to gauge anomaly cancellation in the Standard Model, in which it takes place separately within each generation, in our scenarios anomaly cancellation involves simultaneously quarks and leptons of all three generations. Our models involve, beyond the ordinary quarks and leptons, three heavy right-handed neutrinos. The models with only left-handed FCNCs of Z' involve beyond gZ' and MZ' two real parameters characterizing the charges of all fermions under the U(1)' gauge symmetry and the CKM and PMNS ones in the quark and lepton sectors, respectively. The models with the right-handed FCNCs of Z' involve few additional parameters. Imposing constraints from well measured ΔF = 2 observables we identify a number of interesting correlations that involve e.g. ɛ'/ɛ, Bs,d→ μ+μ-, B → K(K*)ℓ+ℓ-, K+→π+ν ν ¯,KL→π0ν ν ¯ and purely lepton flavour violating decays like μ → eγ, μ → 3e, τ → 3μ and μ - e conversion among others. Also (g - 2)μ,e are considered. The impact of the experimental μ → eγ, μ → 3e and in particular μ - e conversion bounds on rare K and B decays is emphasized.
We construct and validate the selection function of the MARD-Y3 galaxy cluster sample. This sample was selected through optical follow-up of the 2nd ROSAT faint source catalogue with Dark Energy Survey year 3 data. The selection function is modelled by combining an empirically constructed X-ray selection function with an incompleteness model for the optical follow-up. We validate the joint selection function by testing the consistency of the constraints on the X-ray flux–mass and richness–mass scaling relation parameters derived from different sources of mass information: (1) cross-calibration using South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) clusters, (2) calibration using number counts in X-ray, in optical and in both X-ray and optical while marginalizing over cosmological parameters, and (3) other published analyses. We find that the constraints on the scaling relation from the number counts and SPT-SZ cross-calibration agree, indicating that our modelling of the selection function is adequate. Furthermore, we apply a largely cosmology independent method to validate selection functions via the computation of the probability of finding each cluster in the SPT-SZ sample in the MARD-Y3 sample and vice versa. This test reveals no clear evidence for MARD-Y3 contamination, SPT-SZ incompleteness or outlier fraction. Finally, we discuss the prospects of the techniques presented here to limit systematic selection effects in future cluster cosmological studies.
We improve the pNRQCD approach to annihilation processes of heavy quarkonium and make first pNRQCD predictions for exclusive electromagnetic production of heavy quarkonium. We consider strongly coupled quarkonia, i.e., quarkonia that are not Coulombic bound states. Possible strongly coupled quarkonia include excited charmonium and bottomonium states. For these, pNRQCD provides expressions for the decay and exclusive electromagnetic production NRQCD matrix elements that depend on the wavefunctions at the origin and few universal gluon field correlators. We compute electromagnetic decay widths and exclusive production cross sections, and inclusive decay widths into light hadrons for P -wave quarkonia at relative order v$^{2}$ and leading order, respectively. We also compute the decay widths of 2S and 3S bottomonium states into lepton pairs and their ratios with the inclusive widths into light hadrons at relative order v$^{2}$.
Light curves, explosion energies, and remnant masses are calculated for a grid of supernovae resulting from massive helium stars that have been evolved including mass loss. These presupernova stars should approximate the results of binary evolution for stars in interacting systems that lose their envelopes close to the time of helium core ignition. Initial helium star masses are in the range 2.5-40 M⊙, which corresponds to main-sequence masses of about 13-90 M⊙. Common SNe Ib and Ic result from stars whose final masses are approximately 2.5-5.6 M⊙. For heavier stars, a large fraction of collapses lead to black holes, though there is an island of explodability for presupernova masses near 10 M⊙. The median neutron star mass in binaries is 1.35-1.38 M⊙, and the median black hole mass is between 9 and 11 M⊙. Even though black holes less massive than 5 M⊙ are rare, they are predicted down to the maximum neutron star mass. There is no empty "gap," only a less populated mass range. For standard assumptions regarding the explosions and nucleosynthesis, the models predict light curves that are fainter than the brighter common SNe Ib and Ic. Even with a very liberal but physically plausible increase in 56Ni production, the highest-energy models are fainter than 1042.6 erg s-1 at peak, and very few approach that limit. The median peak luminosity ranges from 1042.0 to 1042.3 erg s-1. Possible alternatives to the standard neutrino-powered and radioactive-illuminated models are explored. Magnetars are a promising alternative. Several other unusual varieties of SNe I at both high and low mass are explored.
We present a general formalism to write the decay amplitude for multibody reactions with explicit separation of the rotational degrees of freedom, which are well controlled by the spin of the decay particle, and dynamic functions on the subchannel invariant masses, which require modeling. Using the three-particle kinematics we demonstrate the proposed factorization, named the Dalitz-plot decomposition. The Wigner rotations, which are subtle factors needed by the isobar modeling in the helicity framework, are simplified with the proposed decomposition. Consequently, we are able to provide them in an explicit form suitable for the general case of arbitrary spins. The only unknown model-dependent factors are the isobar line shapes that describe the subchannel dynamics. The advantages of the new decomposition are shown through three examples relevant for the recent discovery of the exotic charmonium candidate Zc(4430 ), the pentaquarks Pc, and the intriguing Λc+→p K-π+ decay.
Following updated and extended measurements of the full angular distribution of the decay Λb→Λ(→pπ−)μ+μ− by the LHCb collaborations, as well as a new measurement of the Λ→pπ− decay asymmetry parameter by the BESIII collaboration, we study the impact of these results on searches for non-standard effects in exclusive b→sμ+μ− decays. To this end, we constrain the Wilson coefficients 9 and 10 of the numerically leading dimension-six operators in the weak effective Hamiltonian, in addition to the relevant nuisance parameters. In stark contrast to previous analyses of this decay mode, the changes in the updated experimental results lead us to find very good compatibility with both the Standard Model and with the b→sμ+μ− anomalies observed in rare B-meson decays. We provide a detailed analysis of the impact of the partial angular distribution, the full angular distribution, and the Λb→Λμ+μ− branching fraction on the Wilson coefficients. In this process, we are also able to constrain the size of the production polarization of the Λb baryon at LHCb.
Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations of the protoplanetary disk around HD 169142 reveal a peculiar structure made of concentric dusty rings: a main ring at ∼20 au, a triple system of rings at ∼55-75 au in millimetric continuum emission, and a perturbed gas surface density from the 12CO,13CO, and C18O (J = 2-1) surface brightness profile. In this Letter, we perform 3D numerical simulations and radiative transfer modeling exploring the possibility that two giant planets interacting with the disk and orbiting in resonant locking can be responsible for the origin of the observed dust inner rings structure. We find that in this configuration the dust structure is actually long lived while the gas mass of the disk is accreted onto the star and the giant planets, emptying the inner region. In addition, we also find that the innermost planet is located at the inner edge of the dust ring, and can accrete mass from the disk, generating a signature in the dust ring shape that can be observed in mm ALMA observations.
We present new 890 μm continuum ALMA observations of five brown dwarfs (BDs) with infrared excess in Lupus I and III, which in combination with four previously observed BDs allowed us to study the millimeter properties of the full known BD disk population of one star-forming region. Emission is detected in five out of the nine BD disks. Dust disk mass, brightness profiles, and characteristic sizes of the BD population are inferred from continuum flux and modeling of the observations. Only one source is marginally resolved, allowing for the determination of its disk characteristic size. We conduct a demographic comparison between the properties of disks around BDs and stars in Lupus. Due to the small sample size, we cannot confirm or disprove a drop in the disk mass over stellar mass ratio for BDs, as suggested for Ophiuchus. Nevertheless, we find that all detected BD disks have an estimated dust mass between 0.2 and 3.2 M⊙; these results suggest that the measured solid masses in BD disks cannot explain the observed exoplanet population, analogous to earlier findings on disks around more massive stars. Combined with the low estimated accretion rates, and assuming that the mm-continuum emission is a reliable proxy for the total disk mass, we derive ratios of Ṁacc/Mdisk that are significantly lower than in disks around more massive stars. If confirmed with more accurate measurements of disk gas masses, this result could imply a qualitatively different relationship between disk masses and inward gas transport in BD disks.
Parametric correlations are studied in several classes of covariant density functional theories (CDFTs) using a statistical analysis in a large parameter hyperspace. In the present manuscript, we investigate such correlations for two specific types of models, namely, for models with density dependent meson exchange and for point coupling models. Combined with the results obtained previously in Ref. [1] for a non-linear meson exchange model, these results indicate that parametric correlations exist in all major classes of CDFTs when the functionals are fitted to the ground state properties of finite nuclei and to nuclear matter properties. In particular, for the density dependence in the isoscalar channel only one parameter is really independent. Accounting for these facts potentially allows one to reduce the number of free parameters considerably.
Single-particle resonances are crucial for exotic nuclei near and beyond the drip lines. Since the majority of nuclei are deformed, the interplay between deformation and orbital structure near threshold becomes very important and can lead to an improved description of exotic nuclei. In this work, the Green's function (GF) method is applied to solve the coupled-channel Dirac equation with quadrupole-deformed Woods-Saxon potentials. The detailed formalism for the partial-wave expansion of the Green's function is presented. A different approach getting exact values for energies and widths of resonant states by the GF method is proposed. Numerical checks are carried out by comparing with our previous implementation of the spherical GF method and the results from the deformed complex momentum representation, the analytical continuation of the coupling constant, and the scattering phase shift methods, and it is proved that the GF method is very effective and reliable for describing resonance states, no matter whether they are narrow or broad, spherical or deformed. Finally, Nilsson levels for bound and resonant orbitals in the halo candidate nucleus 37Mg are calculated from the deformed GF method over a wide range of deformations, and some decisive hints of p-wave halo formation are shown in this nucleus; namely, the crossing between the configurations 1/2[321] and 5/2[312] at deformation parameter β>0.5 may enhance the probability to occupy the 1/2[321] orbital that originates from the 2p3/2 shell.
Direct imaging is a tried and tested method of detecting exoplanets in the near infrared, but has so far not been extended to longer wavelengths. New data at mid-IR wavelengths (8-20{\mu}m) canprovide additional constraints on planetary atmospheric models. We use the VISIR instrumenton the VLT to detect or set stringent limits on the 8.7{\mu}m flux of the four planets surrounding HR8799, and to search for additional companions. We use a novel circularised PSF subtractiontechnique to reduce the stellar signal and obtain instrument limited background levels andobtain optimal flux limits. The BT SETTL isochrones are then used to determine the resultingmass limits. We find flux limits between 0.7 and 3.3 mJy for the J8.9 flux of the differentplanets at better than5{\sigma}level and derive a new mass limit of 30 MJupfor any objects beyond40 AU. While this work has not detected planets in the HR 8799 system at 8.7{\mu}m, it has foundthat an instrument with the sensitivity of VISIR is sufficient to detect at least 4 known hotplanets around close stars, including\b{eta}Pictoris b (1700 K, 19 pc), with more than5{\sigma}certaintyin 10 hours of observing time in the mid-IR.
Following the 1999 analysis of Gambino, Haisch and one of us, we stress that all the recent NLO analyses of ε′/ ε in the Standard Model (SM) suffer from the renormalization scheme dependence present in the electroweak penguin contributions as well as from scale uncertainties in them related to the matching scale μW and in particular to μt in mt(μt). We also reemphasize the important role of isospin-breaking and QED effects in the evaluation of ε′/ ε. Omitting all these effects, as done in the 2015 analysis by RBC-UKQCD collaboration, and choosing as an example the QCD penguin (Q6) and electroweak penguin (Q8) parameters B6(1/2) and B8(3/2) to be B6(1/2)=0.80±0.08 and B8(3/2)=0.76±0.04 at μ=mc=1.3GeV, we find (ε′/ε)SM=(9.4±3.5)×10-4, whereas including them results in (ε′/ε)SM=(5.6±2.4)×10-4. This is an example of an anomaly at the 3.3σ level, which would be missed without these corrections. NNLO QCD contributions to QCD penguins are expected to further enhance this anomaly. We provide a table for ε′/ ε for different values of B6(1/2) and the isospin-breaking parameter Ω ^ eff, that should facilitate monitoring the values of ε′/ ε in the SM when the RBC-UKQCD calculations of hadronic matrix elements including isospin-breaking corrections and QED effects will improve with time.
We carry out an analysis of the full set of ten B¯→D(∗) form factors within the framework of the Heavy-Quark Expansion (HQE) to order (αs,1/mb,1/m2c), both with and without the use of experimental data. This becomes possible due to a recent calculation of these form factors at and beyond the maximal physical recoil using QCD light-cone sum rules, in combination with constraints from lattice QCD, QCD three-point sum rules and unitarity. We find good agreement amongst the various theoretical results, as well as between the theoretical results and the kinematical distributions in B¯→D(∗){e−,μ−}ν¯ measurements. The coefficients entering at the 1/m2c level are found to be of (1), indicating convergence of the HQE. The phenomenological implications of our study include an updated exclusive determination of |Vcb| in the HQE, which is compatible with both the exclusive determination using the BGL parametrization and with the inclusive determination. We also revisit predictions for the lepton-flavour universality ratios RD(∗), the τ polarization observables PD(∗)τ, and the longitudinal polarization fraction FL. Posterior samples for the HQE parameters are provided as ancillary files, allowing for their use in subsequent studies.
The structure and morphology of supernova remnants (SNRs) reflect the properties of the parent supernovae (SNe) and the characteristics of the inhomogeneous environments through which the remnants expand. Linking the morphology of SNRs to anisotropies developed in their parent SNe can be essential to obtain key information on many aspects of the explosion processes associated with SNe. Nowadays, our capability to study the SN-SNR connection has been largely improved thanks to multi-dimensional models describing the long-term evolution from the SN to the SNR as well as to observational data of growing quality and quantity across the electromagnetic spectrum which allow to constrain the models. Here we used the numerical resources obtained in the framework of the ``Accordo Quadro INAF-CINECA (2017)'' together with a CINECA ISCRA Award N.HP10BARP6Y to describe the full evolution of a SNR from the core-collapse to the full-fledged SNR at the age of 2000 years. Our simulations were compared with observations of SNR Cassiopeia A (Cas A) at the age of ∼ 350 years. Thanks to these simulations we were able to link the physical, chemical and morphological properties of a SNR to the physical processes governing the complex phases of the SN explosion.
Recent years have seen considerable progress with ab-initio calculations of the
nuclear structure by non-relativistic many-body methods. Dirac-Brueckner-Hartree-Fock
Theory provides a relativistic ab-intio approach, which is able to reproduce saturation properties
of symmetric nuclear matter without three-body forces. However, so far, the corresponding
equations have been solved only for positive energy states. Negative energy states have
been included for forty years in various approximations, leading to differences in the isospin
dependence. This problem has been solved only recently by a complete solution of the self-
consistent relativistic Brueckner-Hartree-Fock equations in asymmetric nuclear matter. Due
to its numerical complexity, however, it is very difficult to extend the Relativistic Brueckner-
Hartree-Fock theory to the study of finite nuclear systems. Recent efforts will be discussed to
overcome this problem.
The measurement of an astrophysical flux of high-energy neutrinos by IceCube is an important step towards finding the long-sought sources of cosmic rays. Nevertheless, the long exposure neutrino sky map shows no significant indication of point sources so far. This may point to a large population of faint, steady sources or flaring objects as origins of this flux. The most compelling evidence for a neutrino point source so far is the recent observation of the flaring gamma-ray blazar TXS 0506+056 in coincidence with a high-energy neutrino from IceCube. This is a result of a Neutrino Target of Opportunity (NToO) program in which all currently operating Imaging Atmospheric Cherenkov Telescopes (IACTs) take part. The case for TXS 0506+056 being a neutrino source was made stronger by evidence of a 5-month long neutrino flare in 2014-2015.Here we investigate the chances of a detection of a gamma-ray counterpart to a neutrino source with CTA, as a result of a follow-up observation of a neutrino alert. We use the FIRESONG software to simulate different neutrino sources populations, which could be responsible for the diffuse flux of astrophysical neutrinos as measured by IceCube. We scan over parameters that can be used to describe the populations such as density (density rate) for steady (flaring) objects. Several CTA array layouts and instrument response functions are tested in order to derive optimal follow-up strategies and the potential science reach of the NToO program for CTA. We find that following neutrino alerts by IceCube, CTA has a low per alert probability of detecting a matching steady source. However, using a model by Halzen et al. (2018), for neutrino flares similar to that of 2014-2015, we find that CTA will detect a counterpart in as many as one third of the alerts.
The large volume of data expected to be produced by the Belle II experiment presents the opportunity for studies of rare, previously inaccessible processes. Investigating such rare processes in a high data volume environment necessitates a correspondingly high volume of Monte Carlo simulations to prepare analyses and gain a deep understanding of the contributing physics processes to each individual study. This resulting challenge, in terms of computing resource requirements, calls for more intelligent methods of simulation, in particular for processes with very high background rejection rates. This work presents a method of predicting in the early stages of the simulation process the likelihood of relevancy of an individual event to the target study using graph neural networks. The results show a robust training that is integrated natively into the existing Belle II analysis software framework.
Numerically estimating the integral of functions in high dimensional spaces is a non-trivial task. A oft-encountered example is the calculation of the marginal likelihood in Bayesian inference, in a context where a sampling algorithm such as a Markov Chain Monte Carlo provides samples of the function. We present an Adaptive Harmonic Mean Integration (AHMI) algorithm. Given samples drawn according to a probability distribution proportional to the function, the algorithm will estimate the integral of the function and the uncertainty of the estimate by applying a harmonic mean estimator to adaptively chosen regions of the parameter space. We describe the algorithm and its mathematical properties, and report the results using it on multiple test cases.
The time dependent density functional theory is applied to study modes of vibrational excitations in atomic nuclei. The covariant density functional DD-ME2 is adopted. It turns out that DD-ME2 is able to provide simultaneously a satisfactory description of isocalar giant monopole (ISGM), isovector giant dipole (IVGD), and isoscalar giant quadrupole (ISGQ) resonances. The functional is also able to describe very well the soft dipole modes known as pygmy dipole resonances (PDR).
In an interacting neutrino gas, flavor coherence becomes dynamical and can propagate as a collective mode. In particular, tachyonic instabilities can appear, leading to "fast flavor conversion" that is independent of neutrino masses and mixing angles. On the other hand, without neutrino-neutrino interaction, a prepared wave packet of flavor coherence simply dissipates by kinematical decoherence of infinitely many non-collective modes. We reexamine the dispersion relation for fast flavor modes and show that for any wavenumber, there exists a continuum of non-collective modes besides a few discrete collective ones. So for any initial wave packet, both decoherence and collective motion occurs, although the latter typically dominates for a sufficiently dense gas. We derive explicit eigenfunctions for both collective and non-collective modes. If the angular mode distribution of electron-lepton number crosses between positive and negative values, two non-collective modes can merge to become a tachyonic collective mode. We explicitly calculate the interaction strength for this critical point. As a corollary we find that a single crossing always leads to a tachyonic instability. For an even number of crossings, no instability needs to occur.
This thesis seeks to identify and investigate various universal quantum phenomena that are particularly, albeit by far not exclusively, relevant for gravity. In the first part, we study the question of how long a generic quantum system can be approximated as classical. Using a prototypical model of a self-interacting scalar field, we discuss possible scalings of the quantum break-time, after which the classical description breaks down. Subsequently, we apply this analysis to the hypothetical QCD axion. We conclude that the approximation as classically oscillating scalar field is extremely accurate. Next we turn to de Sitter. Our approach is to resolve the classical metric as a multi-graviton state defined on top of Minkowski vacuum. On the one hand, this composite picture of de Sitter is able to reproduce all known (semi)classical properties. On the other hand, it leads a breakdown of the description in terms of a classical metric after the timescale 1/(G H^3), where G and H correspond to Newton’s constant and the Hubble scale, respectively. This finding results in important restrictions on inflationary scenarios. [...]
The location at which life emerged on Earth defined the physical boundary conditions under which the first replicating systems evolved. Nonequilibrium systems were necessary to provide the energy driving these processes. One such nonequilibrium system could have been temperature gradients, found for example across porous rock in hydrothermal vents. The work presented here focuses on the effects of temperature gradients on molecules in these water-filled micro-compartments and on methods how they could be analyzed. [...]
Context. Analyzing the properties of dust and its evolution in the early phases of star formation is crucial to put constraints on the collapse and accretion processes as well as on the pristine properties of planet-forming seeds.
Aims: In this paper, we aim to investigate the variations of the dust grain size in the envelopes of the youngest protostars.
Methods: We analyzed Plateau de Bure interferometric observations at 1.3 and 3.2 mm for 12 Class 0 protostars obtained as part of the CALYPSO survey. We performed our analysis in the visibility domain and derived dust emissivity index (β1-3mm) profiles as a function of the envelope radius at 200-2000 au scales.
Results: Most of the protostellar envelopes show low dust emissivity indices decreasing toward the central regions. The decreasing trend remains after correction of the (potentially optically thick) central region emission, with surprisingly low β1-3mm < 1 values across most of the envelope radii of NGC 1333-IRAS 4A, NGC 1333-IRAS 4B, SVS13B, and Serpens-SMM4.
Conclusions: We discuss the various processes that could explain such low and varying dust emissivity indices at envelope radii 200-2000 au. Our observations of extremely low dust emissivity indices could trace the presence of large (millimeter-size) grains in Class 0 envelopes, in which case our results would point to a radial increase of the dust grain size toward the inner envelope regions. While it is expected that large grains in young protostellar envelopes could be built via grain growth and coagulation, we stress that the typical timescales required to build millimeter grains in current coagulation models are at odds with the youth of our Class 0 protostars. Additional variations in the dust composition could also partly contribute to the low β1-3mm we observe. We find that the steepness of the β1-3mm radial gradient depends strongly on the envelope mass, which might favor a scenario in which large grains are built in high-density protostellar disks and transported to the intermediate envelope radii, for example with the help of outflows and winds.
The light-meson spectrum can be studied by analyzing data from diffractive dissociation of pion or kaon beams. The contributions of the various states that are produced in these reactions are disentangled by the means of partial-wave analysis. A challenge in these analyses is that the partial-wave expansion has to be truncated, i.e. that only a finite subset of the infinitely many partial-wave amplitudes can be inferred from the data. In recent years, different groups have applied regularization techniques in order to determine the contributing waves from the data. However, to obtain meaningful results the choice of the regularization term is crucial. We present our recent developments of wave-selection methods for partial-wave analyses based on simulated data for diffractively produced three-pion events.
We present an alternative method for carrying out a principal-component analysis of Wilson coefficients in standard model effective field theory (SMEFT). The method is based on singular-value decomposition (SVD). The SVD method provides information about the sensitivity of experimental observables to physics beyond the standard model that is not accessible in the Fisher-information method. In principle, the SVD method can also have computational advantages over diagonalization of the Fisher information matrix. We demonstrate the SVD method by applying it to the dimension-6 coefficients for the process of top-quark decay to a b quark and a W boson and use this example to illustrate some pitfalls in widely used fitting procedures. We also outline an iterative procedure for applying the SVD method to dimension-8 SMEFT coefficients.
Context. Large area catalogs of galaxy clusters constructed from ROSAT All-Sky Survey provide the basis for our knowledge of the population of clusters thanks to long-term multiwavelength efforts to follow up observations of these clusters.Aims. The advent of large area photometric surveys superseding previous, in-depth all-sky data allows us to revisit the construction of X-ray cluster catalogs, extending the study to lower cluster masses and higher redshifts and providing modeling of the selection function.Methods. We performed a wavelet detection of X-ray sources and made extensive simulations of the detection of clusters in the RASS data. We assigned an optical richness to each of the 24 788 detected X-ray sources in the 10 382 square degrees of the Baryon Oscillation Spectroscopic Survey area using red sequence cluster finder redMaPPer version 5.2 run on Sloan Digital Sky Survey photometry. We named this survey COnstrain Dark Energy with X-ray (CODEX) clusters.Results. We show that there is no obvious separation of sources on galaxy clusters and active galactic nuclei (AGN) based on the distribution of systems on their richness. This is a combination of an increasing number of galaxy groups and their selection via the identification of X-ray sources either by chance or by groups hosting an AGN. To clean the sample, we use a cut on the optical richness at the level corresponding to the 10% completeness of the survey and include it in the modeling of the cluster selection function. We present the X-ray catalog extending to a redshift of 0.6.Conclusions. The CODEX suvey is the first large area X-ray selected catalog of northern clusters reaching fluxes of 10−13 ergs s−1 cm−2. We provide modeling of the sample selection and discuss the redshift evolution of the high end of the X-ray luminosity function (XLF). Our results on z < 0.3 XLF agree with previous studies, while we provide new constraints on the 0.3 < z < 0.6 XLF. We find a lack of strong redshift evolution of the XLF, provide exact modeling of the effect of low number statistics and AGN contamination, and present the resulting constraints on the flat ΛCDM.Key words: surveys / catalogs / large-scale structure of Universe⋆ The catalog of clusters is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/638/A114
We study the impact of anomalous couplings in the Higgs sector on the shape of the Higgs boson pair invariant mass distribution at NLO. Our analysis is based on a five-dimensional coupling parameter space relevant for Higgs boson pair production in gluon fusion, in the framework of a non-linear Effective Field Theory. In particular, we present a clustering procedure into certain shape types based on unsupervised machine learning, with the aim to infer information about the underlying parameter space from a given shape type.
We propose to replace the exact amplitudes used in MC event generators for trained Machine Learning regressors, with the aim of speeding up the evaluation of {\it slow} amplitudes. As a proof of concept, we study the process $gg \to ZZ$ whose LO amplitude is loop induced. We show that gradient boosting machines like $\texttt{XGBoost}$ can predict the fully differential distributions with errors below $0.1 \%$, and with prediction times $\mathcal{O}(10^3)$ faster than the evaluation of the exact function. This is achieved with training times $\sim 7$ minutes and regressors of size $\lesssim 30$~Mb. These results suggest a possible new avenue to speed up MC event generators.
Unilamellar lipid vesicles can serve as model for protocells. We present a vesicle fission mechanism in a thermal gradient under flow in a convection chamber, where vesicles cycle cold and hot regions periodically. Crucial to obtain fission of the vesicles in this scenario is a temperature-induced membrane phase transition that vesicles experience multiple times. We model the temperature gradient of the chamber with a capillary to study single vesicles on their way through the temperature gradient in an external field of shear forces. Starting in the gel-like phase the spherical vesicles are heated above their main melting temperature resulting in a dumbbell-deformation. Further downstream a temperature drop below the transition temperature induces splitting of the vesicles without further physical or chemical intervention. This mechanism also holds for less cooperative systems, as shown here for a lipid alloy with a broad transition temperature width of 8 K. We find a critical tether length that can be understood from the transition width and the locally applied temperature gradient. This combination of a temperature-induced membrane phase transition and realistic flow scenarios as given e.g. in a white smoker enable a fission mechanism that can contribute to the understanding of more advanced protocell cycles.
We revisit the decay Λ0b→Λ+cℓ−ν¯ (ℓ=e,μ,τ) with a subsequent two-body decay Λ+c→Λ0π+ in the Standard Model and in generic New Physics models. The decay's joint four-differential angular distribution can be expressed in terms of ten angular observables, assuming negligible polarization of the initial Λb state. We present compact analytical results for all angular observables, which enables us to discuss their possible New Physics reach. We find that the decay at hand probes more and complementary independent combinations of Wilson coefficients compared to its mesonic counter parts B¯→D(∗)ℓ−ν¯. Our result for the angular distribution is at variance with some of the results on scalar-vector interference terms in the literature. We provide numerical estimates for all angular observables based on lattice-QCD results for the Λb→Λc form factors and account for a recent measurement of the parity-violating parameter in Λ+c→Λ0π+ decays by BESIII. A numerical implementation of our results is made publicly available as part of the EOS software.
Nuclear structure models built from phenomenological mean fields, the effective nucleon–nucleon interactions (or Lagrangians), and the realistic bare nucleon–nucleon interactions are reviewed. The success of covariant density functional theory (CDFT) to describe nuclear properties and its influence on Brueckner theory within the relativistic framework are focused upon. The challenges and ambiguities of predictions for unstable nuclei without data or for high-density nuclear matter, arising from relativistic density functionals, are discussed. The basic ideas in building an ab initio relativistic density functional for nuclear structure from ab initio calculations with realistic nucleon–nucleon interactions for both nuclear matter and finite nuclei are presented. The current status of fully self-consistent relativistic Brueckner–Hartree–Fock (RBHF) calculations for finite nuclei or neutron drops (ideal systems composed of a finite number of neutrons and confined within an external field) is reviewed. The guidance and perspectives towards an ab initio covariant density functional theory for nuclear structure derived from the RBHF results are provided.
The goal of blinding is to hide an experiment’s critical results – here the inferred cosmological parameters – until all decisions affecting its analysis have been finalized. This is especially important in the current era of precision cosmology, when the results of any new experiment are closely scrutinized for consistency or tension with previous results. In analyses that combine multiple observational probes, like the combination of galaxy clustering and weak lensing in the Dark Energy Survey (DES), it is challenging to blind the results while retaining the ability to check for (in)consistency between different parts of the data. We propose a simple new blinding transformation, which works by modifying the summary statistics that are input to parameter estimation, such as two-point correlation functions. The transformation shifts the measured statistics to new values that are consistent with (blindly) shifted cosmological parameters while preserving internal (in)consistency. We apply the blinding transformation to simulated data for the projected DES Year 3 galaxy clustering and weak lensing analysis, demonstrating that practical blinding is achieved without significant perturbation of internal-consistency checks, as measured here by degradation of the χ^2 between the data and best-fitting model. Our blinding method’s performance is expected to improve as experiments evolve to higher precision and accuracy.
Cosmic voids gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint on degree scales. We use the simulated CMB lensing convergence map from the Marenostrum Institut de Ciencias de l’Espai (MICE) N-body simulation to calibrate our detection strategy for a given void definition and galaxy tracer density. We then identify cosmic voids in Dark Energy Survey (DES) Year 1 data and stack the Planck 2015 lensing convergence map on their locations, probing the consistency of simulated and observed void lensing signals. When fixing the shape of the stacked convergence profile to that calibrated from simulations, we find imprints at the 3σ significance level for various analysis choices. The best measurement strategies based on the MICE calibration process yield S/N ≈ 4 for DES Y1, and the best-fitting amplitude recovered from the data is consistent with expectations from MICE (A ≈ 1). Given these results as well as the agreement between them and N-body simulations, we conclude that the previously reported excess integrated Sachs–Wolfe (ISW) signal associated with cosmic voids in DES Y1 has no counterpart in the Planck CMB lensing map.
The compact binary radio pulsar system J0453+1559 consists of a recycled pulsar as primary component of 1.559(5) M ⊙ and an unseen companion star of 1.174(4) M ⊙. Because of the relatively large orbital eccentricity of e = 0.1125, it was argued that the companion is a neutron star (NS), making it the NS with the lowest accurately determined mass to date. However, a direct observational determination of the nature of the companion is currently not feasible. Moreover, state-of-the-art stellar evolution and supernova modeling are contradictory concerning the possibility of producing such a low-mass NS remnant. Here we challenge the NS interpretation by reasoning that the lower-mass component could instead be a white dwarf born in a thermonuclear electron-capture supernova (tECSN) event, in which oxygen-neon deflagration in the degenerate stellar core of an ultra-stripped progenitor ejects several 0.1 M ⊙ of matter and leaves a bound ONeFe white dwarf as the second-formed compact remnant. We determine the ejecta mass and remnant kick needed in this scenario to explain the properties of PSR J0453+1559 by a NS-white dwarf system. More work on tECSNe is needed to assess the viability of this scenario.
Confining hidden sectors are an attractive possibility for physics beyond the Standard Model (SM). They are especially motivated by neutral naturalness theories, which reconcile the lightness of the Higgs with the strong constraints on colored top partners. We study hidden QCD with one light quark flavor, coupled to the SM via effective operators suppressed by the mass M of new electroweak-charged particles. This effective field theory is inspired by a new tripled top model of supersymmetric neutral naturalness. The hidden sector is accessed primarily via the Z and Higgs portals, which also mediate the decays of the hidden mesons back to SM particles. We find that exotic Z decays at the LHC and future Z factories provide the strongest sensitivity to this scenario, and we outline a wide array of searches. For a larger hidden confinement scale Λ ∼ O (10) GeV, the exotic Z decays dominantly produce final states with two hidden mesons. ATLAS and CMS can probe their prompt decays up to M ∼ 3 TeV at the high luminosity phase, while a TeraZ factory would extend the reach up to M ∼ 20 TeV through a combination of searches for prompt and displaced signals. For smaller Λ ∼ O (1) GeV, the Z decays to the hidden sector produce jets of hidden mesons, which are long-lived. LHCb will be a powerful probe of these emerging jets. Furthermore, the light hidden vector meson could be detected by proposed dark photon searches.
We present high angular resolution (∼80 mas) ALMA continuum images of the SN 1987A system, together with CO J = 2 \to 1, J = 6 \to 5, and SiO J = 5 \to 4 to J = 7 \to 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in Hα images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO J = 6 \to 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In these regions, carbonaceous dust grains might have formed after dissociation of CO. The dust grains would have cooled by radiation, and subsequent collisions of grains with gas would also cool the gas, suppressing the CO J = 6 \to 5 intensity. The data show a dust peak spatially coincident with the molecular hole seen in previous ALMA CO J = 2 \to 1 and SiO J = 5 \to 4 images. That dust peak, combined with CO and SiO line spectra, suggests that the dust and gas could be at higher temperatures than the surrounding material, though higher density cannot be totally excluded. One of the possibilities is that a compact source provides additional heat at that location. Fits to the far-infrared-millimeter spectral energy distribution give ejecta dust temperatures of 18-23 K. We revise the ejecta dust mass to M dust = 0.2-0.4 {M}⊙ for carbon or silicate grains, or a maximum of <0.7 {M}⊙ for a mixture of grain species, using the predicted nucleosynthesis yields as an upper limit.
We argue that the tree-level graviton-scalar scattering in the Regge limit is unitarized by non-perturbative effects within General Relativity alone, that is without resorting to any extension thereof. At Planckian energy the back reaction of the incoming graviton on the background geometry produces a non-perturbative plane wave which softens the UV-behavior in turn. Our amplitude interpolates between the perturbative graviton-scalar scattering at low energy and scattering on a classical plane wave in the Regge limit that is bounded for all values of s.
We test exact marginality of the deformation describing the blow-up of a zero- size D(-1) brane bound to a background of D3-branes by analyzing the equations of motion of superstring field theory to third order in the size. In the process we review the derivation of the instanton profile from string theory, extending it to include α'-corrections.
We present a blind time-delay cosmographic analysis for the lens system DES J0408−5354. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more information at the cost of increased modelling complexity with respect to previously analysed systems. We perform detailed modelling of the mass distribution for this lens system using three band Hubble Space Telescope imaging. We combine the measured time delays, line-of-sight central velocity dispersion of the deflector, and statistically constrained external convergence with our lens models to estimate two cosmological distances. We measure the ‘effective’ time-delay distance corresponding to the redshifts of the deflector and the lensed quasar |$D_{\Delta t}^{\rm eff}=$||$3382_{-115}^{+146}$| Mpc and the angular diameter distance to the deflector D_d = |$1711_{-280}^{+376}$| Mpc, with covariance between the two distances. From these constraints on the cosmological distances, we infer the Hubble constant H_0= |$74.2_{-3.0}^{+2.7}$| km s^−1 Mpc^−^1 assuming a flat ΛCDM cosmology and a uniform prior for Ω_m as |$\Omega _{\rm m} \sim \mathcal {U}(0.05, 0.5)$|. This measurement gives the most precise constraint on H_0 to date from a single lens. Our measurement is consistent with that obtained from the previous sample of six lenses analysed by the H_0 Lenses in COSMOGRAIL’s Wellspring (H0LiCOW) collaboration. It is also consistent with measurements of H_0 based on the local distance ladder, reinforcing the tension with the inference from early Universe probes, for example, with 2.2σ discrepancy from the cosmic microwave background measurement.
The doubled target space of the fundamental closed string is identified with its phase space and described by an almost para-Hermitian geometry. We explore this setup in the context of group manifolds which admit a maximally isotropic subgroup. This leads to a formulation of the Poisson-Lie σ-model and Poisson-Lie T-duality in terms of para-Hermitian geometry. The emphasis is put on so called half-integrable setups where only one of the Lagrangian subspaces of the doubled space has to be integrable. Using the dressing coset construction in Poisson-Lie T-duality, we extend our construction to more general coset spaces. This allows to explicitly obtain a huge class of para-Hermitian geometries. Each of them is automatically equipped which a generalized frame field, required for consistent generalized Scherk-Schwarz reductions. As examples we present integrable λ- and η-deformations on the three- and two-sphere.
The effect of galactic orbits on a galaxy's internal evolution within a galaxy cluster environment has been the focus of heated debate in recent years. To understand this connection, we use both the (0.5 Gpc)3 and the Gpc3 boxes from the cosmological hydrodynamical simulation set Magneticum Pathfinder. We investigate the velocity anisotropy, phase space, and the orbital evolution of up to ∼5 × 105 resolved satellite galaxies within our sample of 6776 clusters with M_{vir} > 10^{14} M_{⊙ } at low redshift, which we also trace back in time. In agreement with observations, we find that star-forming satellite galaxies inside galaxy clusters are characterized by more radially dominated orbits, independent of cluster mass. Furthermore, the vast majority of star-forming satellite galaxies stop forming stars during their first passage. We find a strong dichotomy both in line-of-sight and radial phase space between star-forming and quiescent galaxies, in line with observations. The tracking of individual orbits shows that the star formation of almost all satellite galaxies drops to zero within 1 Gyr after infall. Satellite galaxies that are able to remain star forming longer are characterized by tangential orbits and high stellar mass. All this indicates that in galaxy clusters the dominant quenching mechanism is ram-pressure stripping.
Turbulence is the natural state of many weakly collisional space and astrophysical plasmas.
Prominent examples range from the near-Earth solar wind, to more distant astrophysical systems such as the warm interstellar medium, hot accretion flows, and galaxy clusters. In low-collisionality turbulent plasmas, it is anticipated theoretically and documented observationally that the electromagnetic energy cascade extends beyond the inertial, magnetohydrodynamic range into the plasma kinetic range of scales. Upon transition into the kinetic range, below the ion gyroradius and the ion inertial scale, the character of the turbulence changes significantly compared to the magnetohydrodynamic turbulence. The nature of this kinetic-scale turbulence is presently the subject of ongoing investigations, with important implications for the general thermodynamic properties of weakly collisional plasmas.