Context. Pre-main-sequence variability characteristics can be used to probe the physical processes leading to the formation and initial evolution of both stars and planets.
Aims: The photometric variability of pre-main-sequence stars is studied at optical wavelengths to explore star-disk interactions, accretion, spots, and other physical mechanisms associated with young stellar objects.
Methods: We observed a field of 16' × 16' in the star-forming region Pelican Nebula (IC 5070) at BVRI wavelengths for 90 nights spread over one year in 2012-2013. More than 250 epochs in the VRI bands are used to identify and classify variables up to V ∼ 21 mag. Their physical association with the cluster IC 5070 is established based on the parallaxes and proper motions from the Gaia second data release (DR2). Multiwavelength photometric data are used to estimate physical parameters based on the isochrone fitting and spectral energy distributions.
Results: We present a catalog of optical time-series photometry with periods, mean magnitudes, and classifications for 95 variable stars including 67 pre-main-sequence variables towards star-forming region IC 5070. The pre-main-sequence variables are further classified as candidate classical T Tauri and weak-line T Tauri stars based on their light curve variations and the locations on the color-color and color-magnitude diagrams using optical and infrared data together with Gaia DR2 astrometry. Classical T Tauri stars display variability amplitudes up to three times the maximum fluctuation in disk-free weak-line T Tauri stars, which show strong periodic variations. Short-term variability is missed in our photometry within single nights. Several classical T Tauri stars display long-lasting (≥10 days) single or multiple fading and brightening events of up to two magnitudes at optical wavelengths. The typical mass and age of the pre-main-sequence variables from the isochrone fitting and spectral energy distributions are estimated to be ≤1 M_⊙ and ∼2 Myr, respectively. We do not find any correlation between the optical amplitudes or periods with the physical parameters (mass and age) of pre-main-sequence stars.
Conclusions: The low-mass pre-main-sequence stars in the Pelican Nebula region display distinct variability and color trends and nearly 30% of the variables exhibit strong periodic signatures attributed to cold spot modulations. In the case of accretion bursts and extinction events, the average amplitudes are larger than one magnitude at optical wavelengths. These optical magnitude fluctuations are stable on a timescale of one year.

Full Tables 1 and 2 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/qcat?J/A+A/627/A135

We present a detailed analysis of the effect of an observationally determined dark matter (DM) velocity distribution function (VDF) of the Milky Way (MW) on DM direct detection rates. We go beyond local kinematic tracers and use rotation curve data up to 200 kpc to construct a MW mass model and self-consistently determine the local phase-space distribution of DM. This approach mitigates any incomplete understanding of local dark matter-visible matter degeneracies that can affect the determination of the VDF. Comparing with the oft used Standard Halo Model (SHM), which assumes an isothermal VDF, we look at how the tail of the empirically determined VDF alters our interpretation of the present direct detection WIMP DM cross section exclusion limits. While previous studies have suggested a very large difference (of more than an order of magnitude) in the bounds at low DM masses, we show that accounting for the detector response at low threshold energies, the difference is still significant although less extreme. The change in the number of signal events, when using the empirically determined DM VDF in contrast to the SHM VDF, is most prominent for low DM masses for which the shape of the recoil energy spectrum depends sensitively on the detector threshold energy as well as detector response near the threshold. We demonstrate that these trends carry over to the respective DM exclusion limits, modulo detailed understanding of the experimental backgrounds. With the unprecedented precision of astrometric data in the GAIA era, use of observationally determined DM phase space will become a critical and necessary ingredient for DM searches. We provide an accurate fit to the current best observationally determined DM VDF (and self-consistent local DM density) for use in analyzing current DM direct detection data by the experimental community.

This work explores the detailed chemistry of the Milky Way bulge using the HERMES spectrograph on the Anglo-Australian Telescope. Here, we present the abundance ratios of 13 elements for 832 red giant branch and clump stars along the minor bulge axis at latitudes b = -10^○, - 7.5^○, and -5^○. Our results show that none of the abundance ratios vary significantly with latitude. We also observe disc-like [Na/Fe] abundance ratios, which indicate that the bulge does not contain helium-enhanced populations as observed in some globular clusters. Helium enhancement is therefore not the likely explanation for the double red-clump observed in the bulge. We confirm that bulge stars mostly follow abundance trends observed in the disc. However, this similarity is not confirmed across all elements and metallicity regimes. The more metal-poor bulge population at [Fe/H] ≲ - 0.8 is enhanced in the elements associated with core collapse supernovae (SNeII). In addition, the [La/Eu] abundance ratio suggests higher r-process contribution, and likely higher star formation in the bulge compared to the disc. This highlights the complex evolution in the bulge, which should be investigated further, both in terms of modelling; and with additional observations of the inner Galaxy.

Asteroids and other Small Solar System Bodies (SSSBs) are of high general and scientific interest in many aspects. The origin, formation, and evolution of our Solar System (and other planetary systems) can be better understood by analysing the constitution and physical properties of small bodies in the Solar System. Currently, two space missions (Hayabusa2, OSIRIS-REx) have recently arrived at their respective targets and will bring a sample of the asteroids back to Earth. Other small body missions have also been selected by, or proposed to, space agencies. The threat posed to our planet by near-Earth objects (NEOs) is also considered at the international level, and this has prompted dedicated research on possible mitigation techniques. The DART mission, for example, will test the kinetic impact technique. Even ideas for industrial exploitation have risen during the last years. Lastly, the origin of water and life on Earth appears to be connected to asteroids. Hence, future space mission projects will undoubtedly target some asteroids or other SSSBs. In all these cases and research topics, specific knowledge of the structure and mechanical behaviour of the surface as well as the bulk of those celestial bodies is crucial. In contrast to large telluric planets and dwarf planets, a large proportion of such small bodies is believed to consist of gravitational aggregates (`rubble piles') with no—or low—internal cohesion, with varying macro-porosity and surface properties (from smooth regolith covered terrain, to very rough collection of boulders), and varying topography (craters, depressions, ridges). Bodies with such structure can sustain some plastic deformation without being disrupted in contrast to the classical visco-elastic models that are generally valid for planets, dwarf planets, and large satellites. These SSSBs are hence better described through granular mechanics theories, which have been a subject of intense theoretical, experimental, and numerical research over the last four decades. This being the case, it has been necessary to use the theoretical, numerical and experimental tools developed within soil mechanics, granular dynamics, celestial mechanics, chemistry, condensed matter physics, planetary and computer sciences, to name the main ones, in order to understand the data collected and analysed by observational astronomy (visible, thermal, and radio), and different space missions. In this paper, we present a review of the multi-disciplinary research carried out by these different scientific communities in an effort to study SSSBs.

A correlation between proto-planetary disc radii and sub-mm fluxes has been recently reported. In this letter, we show that the correlation is a sensitive probe of grain growth processes. Using models of grain growth and drift, we have shown in a companion paper that the observed disc radii trace where the dust grains are large enough to have a significant sub-mm opacity. We show that the observed correlation emerges naturally if the maximum grain size is set by radial drift, implying relatively low values of the viscous α parameter ≲0.001. In this case, the relation has an almost universal normalization, while if the grain size is set by fragmentation the flux at a given radius depends on the dust-to-gas ratio. We highlight two observational consequences of the fact that radial drift limits the grain size. The first is that the dust masses measured from the sub-mm could be overestimated by a factor of a few. The second is that the correlation should be present also at longer wavelengths (e.g. 3mm), with a normalization factor that scales as the square of the observing frequency as in the optically thick case.

We review open questions and prospects for progress in ultrahigh-energy cosmic ray (UHECR) research, based on a series of discussions that took place during the `The High-Energy Universe: Gamma-Ray, Neutrino, and Cosmic-ray Astronomy' MIAPP workshop in 2018. Specifically, we overview open questions on the origin of the bulk of UHECRs, the UHECR mass composition, the origin of the end of the cosmic-ray spectrum, the transition from Galactic to extragalactic cosmic rays, the effect of magnetic fields on the trajectories of UHECRs, anisotropy expectations for specific astrophysical scenarios, hadronic interactions, and prospects for discovering neutral particles as well as new physics at ultrahigh energies. We also briefly present upcoming and proposed UHECR experiments and discuss their projected science reach.

We study the properties of the Sydney University Molonglo Sky Survey (SUMSS) 843 MHz radio active galactic nuclei (AGNs) population in galaxy clusters from two large catalogues created using the Dark Energy Survey (DES): ∼11 800 optically selected RM-Y3 and ∼1000 X-ray selected MARD-Y3 clusters. We show that cluster radio loud AGNs are highly concentrated around cluster centres to |$z$| ∼ 1. We measure the halo occupation number for cluster radio AGNs above a threshold luminosity, finding that the number of radio AGNs per cluster increases with cluster halo mass as N ∝ M^1.2 ± 0.1 (N ∝ M^0.68 ± 0.34) for the RM-Y3 (MARD-Y3) sample. Together, these results indicate that radio mode feedback is favoured in more massive galaxy clusters. Using optical counterparts for these sources, we demonstrate weak redshift evolution in the host broad-band colours and the radio luminosity at fixed host galaxy stellar mass. We use the redshift evolution in radio luminosity to break the degeneracy between density and luminosity evolution scenarios in the redshift trend of the radio AGNs luminosity function (LF). The LF exhibits a redshift trend of the form (1 + |$z$|⁠)^γ in density and luminosity, respectively, of γ_D = 3.0 ± 0.4 and γ_P = 0.21 ± 0.15 in the RM-Y3 sample, and γ_D = 2.6 ± 0.7 and γ_P = 0.31 ± 0.15 in MARD-Y3. We discuss the physical drivers of radio mode feedback in cluster AGNs, and we use the cluster radio galaxy LF to estimate the average radio-mode feedback energy as a function of cluster mass and redshift and compare it to the core (<0.1R_500) X-ray radiative losses for clusters at |$z$| < 1.

Observational cosmology in the next decade will rely on probes of the distribution of matter in the redshift range between $0<z<3$ to elucidate the nature of dark matter and dark energy. In this redshift range, galaxy formation is known to have a significant impact on observables such as two-point correlations of galaxy shapes and positions, altering their amplitude and scale dependence beyond the expected statistical uncertainty of upcoming experiments at separations under 10 Mpc. Successful extraction of information in such a regime thus requires, at the very least, unbiased models for the impact of galaxy formation on the matter distribution, and can benefit from complementary observational priors. This work reviews the current state of the art in the modelling of baryons for cosmology, from numerical methods to approximate analytical prescriptions, and makes recommendations for studies in the next decade, including a discussion of potential probe combinations that can help constrain the role of baryons in cosmological studies. We focus, in particular, on the modelling of the matter power spectrum, $P(k,z)$, as a function of scale and redshift, and of the observables derived from this quantity. This work is the result of a workshop held at the University of Oxford in November of 2018.

Weak lensing by large-scale structure is a powerful probe of cosmology and of the dark universe. This cosmic shear technique relies on the accurate measurement of the shapes and redshifts of background galaxies and requires precise control of systematic errors. Monte Carlo control loops (MCCL) is a forward modeling method designed to tackle this problem. It relies on the ultra fast image generator (UFig) to produce simulated images tuned to match the target data statistically, followed by calibrations and tolerance loops. We present the first end-to-end application of this method, on the Dark Energy Survey (DES) Year 1 wide field imaging data. We simultaneously measure the shear power spectrum Cℓ and the redshift distribution n(z) of the background galaxy sample. The method includes maps of the systematic sources, point spread function (PSF), an approximate Bayesian computation (ABC) inference of the simulation model parameters, a shear calibration scheme, and a fast method to estimate the covariance matrix. We find a close statistical agreement between the simulations and the DES Y1 data using an array of diagnostics. In a nontomographic setting, we derive a set of Cℓ and n(z) curves that encode the cosmic shear measurement, as well as the systematic uncertainty. Following a blinding scheme, we measure the combination of Ωm, σ8, and intrinsic alignment amplitude AIA, defined as S8DIA=σ8(Ωm/0.3)0.5DIA, where DIA=1-0.11(AIA-1). We find S8DIA=0.895-0.039+0.054, where systematics are at the level of roughly 60% of the statistical errors. We discuss these results in the context of earlier cosmic shear analyses of the DES Y1 data. Our findings indicate that this method and its fast runtime offer good prospects for cosmic shear measurements with future wide-field surveys.

We present a sample of galaxies with the Dark Energy Survey (DES) photometry that replicates the properties of the BOSS CMASS sample. The CMASS galaxy sample has been well characterized by the Sloan Digital Sky Survey (SDSS) collaboration and was used to obtain the most powerful redshift-space galaxy clustering measurements to date. A joint analysis of redshift-space distortions (such as those probed by CMASS from SDSS) and a galaxy–galaxy lensing measurement for an equivalent sample from DES can provide powerful cosmological constraints. Unfortunately, the DES and SDSS-BOSS footprints have only minimal overlap, primarily on the celestial equator near the SDSS Stripe 82 region. Using this overlap, we build a robust Bayesian model to select CMASS-like galaxies in the remainder of the DES footprint. The newly defined DES-CMASS (DMASS) sample consists of 117 293 effective galaxies covering |$1244\,\deg ^2$|⁠. Through various validation tests, we show that the DMASS sample selected by this model matches well with the BOSS CMASS sample, specifically in the South Galactic cap (SGC) region that includes Stripe 82. Combining measurements of the angular correlation function and the clustering-z distribution of DMASS, we constrain the difference in mean galaxy bias and mean redshift between the BOSS CMASS and DMASS samples to be |$\Delta b = 0.010^{+0.045}_{-0.052}$| and |$\Delta z = \left(3.46^{+5.48}_{-5.55} \right) \times 10^{-3}$| for the SGC portion of CMASS, and |$\Delta b = 0.044^{+0.044}_{-0.043}$| and |$\Delta z= (3.51^{+4.93}_{-5.91}) \times 10^{-3}$| for the full CMASS sample. These values indicate that the mean bias of galaxies and mean redshift in the DMASS sample are consistent with both CMASS samples within 1σ.

Cosmic voids offer an extraordinary opportunity to study the effects of massive neutrinos on cosmological scales. Because they are freely streaming, neutrinos can penetrate the interior of voids more easily than cold dark matter or baryons, which makes their relative contribution to the mass budget in voids much higher than elsewhere in the Universe. In simulations it has recently been shown how various characteristics of voids in the matter distribution are affected by neutrinos, such as their abundance, density profiles, dynamics, and clustering properties. However, the tracers used to identify voids in observations (e.g., galaxies or halos) are affected by neutrinos as well, and isolating the unique neutrino signatures inherent to voids becomes more difficult. In this paper we make use of the DEMNUni suite of simulations to investigate the clustering bias of voids in Fourier space as a function of their core density and compensation. We find a clear dependence on the sum of neutrino masses that remains significant even for void statistics extracted from halos. In particular, we observe that the amplitude of the linear void bias increases with neutrino mass for voids defined in dark matter, whereas this trend gets reversed and slightly attenuated when measuring the relative void-halo bias using voids identified in the halo distribution. Finally, we argue how the original behaviour can be restored when considering observations of the total matter distribution (e.g. via weak lensing), and comment on scale-dependent effects in the void bias that may provide additional information on neutrinos in the future.

A guiding principle in self-assembly is that, for high production yield, nucleation of structures must be significantly slower than their growth. However, details of the mechanism that impedes nucleation are broadly considered irrelevant. Here, we analyze self-assembly into finite-sized target structures employing mathematical modeling. We investigate two key scenarios to delay nucleation: (i) by introducing a slow activation step for the assembling constituents and, (ii) by decreasing the dimerization rate. These scenarios have widely different characteristics. While the dimerization scenario exhibits robust behavior, the activation scenario is highly sensitive to demographic fluctuations. These demographic fluctuations ultimately disfavor growth compared to nucleation and can suppress yield completely. The occurrence of this stochastic yield catastrophe does not depend on model details but is generic as soon as number fluctuations between constituents are taken into account. On a broader perspective, our results reveal that stochasticity is an important limiting factor for self-assembly and that the specific implementation of the nucleation process plays a significant role in determining the yield.

Local, manifestly dual-conformally invariant loop integrands are now known for all finite quantities associated with observables in planar, maximally supersymmetric Yang-Mills theory through three loops. These representations, however, are not infrared-finite term by term and therefore require regularization; and even using a regulator consistent with dual-conformal invariance, ordinary methods of loop integration would naïvely obscure this symmetry. In this work, we show how any planar loop integral through at least two loops can be systematically regulated and evaluated directly in terms of strictly finite, manifestly dual-conformal Feynman-parameter integrals. We apply these methods to the case of the two-loop ratio and remainder functions for six particles, reproducing the known results in terms of individually regulated local loop integrals, and we comment on some of the novelties that arise for this regularization scheme not previously seen at one loop.

We present an improved determination of the Hubble constant from Hubble Space Telescope (HST) observations of 70 long-period Cepheids in the Large Magellanic Cloud (LMC). These were obtained with the same WFC3 photometric system used to measure extragalactic Cepheids in the hosts of SNe Ia. Gyroscopic control of HST was employed to reduce overheads while collecting a large sample of widely separated Cepheids. The Cepheid period-luminosity relation provides a zero-point-independent link with 0.4% precision between the new 1.2% geometric distance to the LMC from detached eclipsing binaries (DEBs) measured by Pietrzyński et al. and the luminosity of SNe Ia. Measurements and analysis of the LMC Cepheids were completed prior to knowledge of the new DEB LMC distance. Combined with a refined calibration of the count-rate linearity of WFC3-IR with 0.1% precision, these three improved elements together reduce the overall uncertainty in the geometric calibration of the Cepheid distance ladder based on the LMC from 2.5% to 1.3%. Using only the LMC DEBs to calibrate the ladder, we find H ₀ = 74.22 ± 1.82 km s^-1 Mpc^-1 including systematic uncertainties, 3% higher than before for this particular anchor. Combining the LMC DEBs, masers in NGC 4258, and Milky Way parallaxes yields our best estimate: H ₀ = 74.03 ± 1.42 km s^-1 Mpc^-1, including systematics, an uncertainty of 1.91%-15% lower than our best previous result. Removing any one of these anchors changes H ₀ by less than 0.7%. The difference between H ₀ measured locally and the value inferred from Planck CMB and ΛCDM is 6.6 ± 1.5 km s^-1 Mpc^-1 or 4.4σ (P = 99.999% for Gaussian errors) in significance, raising the discrepancy beyond a plausible level of chance. We summarize independent tests showing that this discrepancy is not attributable to an error in any one source or measurement, increasing the odds that it results from a cosmological feature beyond ΛCDM.

We calculate the contributions to the two-loop scattering amplitudes h → gg, h → ggg and h\to q\overline{q}g that arise from a modified trilinear Higgs coupling λ. Analytic expressions are obtained by performing an asymptotic expansion near the limit of infinitely heavy top quark. The calculated amplitudes are necessary to study the impact of the O(λ ) corrections to the transverse momentum distributions ( p _T,h ) in single-Higgs production at hadron colliders for low and moderate values of p _{T, h} .

Relativistic heavy ion collisions produce nuclei-sized droplets of quark-gluon plasma whose expansion is well described by viscous hydrodynamic calculations. Over the past half decade, this formalism was also found to apply to smaller droplets closer to the size of individual nucleons, as produced in p +p and p +A collisions. The hydrodynamic paradigm was further tested with a variety of collision species, including p +Au ,d +Au , and ³He+Au producing droplets with different geometries. Nevertheless, questions remain regarding the importance of pre-hydrodynamic evolution and the exact medium properties during the hydrodynamic evolution phase, as well as the applicability of alternative theories that argue the agreement with hydrodynamics is accidental. In this work we explore options for new collision geometries including p +O and O +O proposed for running at the Large Hadron Collider, as well as ⁴He+Au ,C +Au ,O +Au , and ^Be,9₇+Au at the Relativistic Heavy Ion Collider.

An understanding of astrophysical feedback is important for constraining models of galaxy formation and for extracting cosmological information from current and future weak lensing surveys. The thermal Sunyaev-Zel’dovich effect, quantified via the Compton-y parameter, is a powerful tool for studying feedback, because it directly probes the pressure of the hot, ionized gas residing in dark matter halos. Cross-correlations between galaxies and maps of Compton-y obtained from cosmic microwave background surveys are sensitive to the redshift evolution of the gas pressure, and its dependence on halo mass. In this work, we use galaxies identified in year one data from the Dark Energy Survey and Compton-y maps constructed from Planck observations. We find highly significant (roughly 12σ) detections of galaxy-y cross-correlation in multiple redshift bins. By jointly fitting these measurements as well as measurements of galaxy clustering, we constrain the halo bias-weighted, gas pressure of the Universe as a function of redshift between 0.15≲z≲0.75. We compare these measurements to predictions from hydrodynamical simulations, allowing us to constrain the amount of thermal energy in the halo gas relative to that resulting from gravitational collapse.

We propose a new strategy for searching for dark matter axions using tunable cryogenic plasmas. Unlike current experiments, which repair the mismatch between axion and photon masses by breaking translational invariance (cavity and dielectric haloscopes), a plasma haloscope enables resonant conversion by matching the axion mass to a plasma frequency. A key advantage is that the plasma frequency is unrelated to the physical size of the device, allowing large conversion volumes. We identify wire metamaterials as a promising candidate plasma, wherein the plasma frequency can be tuned by varying the interwire spacing. For realistic experimental sizes, we estimate competitive sensitivity for axion masses of 35–400  μeV, at least.

We introduce a galaxy cluster mass observable, μ_⋆, based on the stellar masses of cluster members, and we present results for the Dark Energy Survey (DES) Year 1 (Y1) observations. Stellar masses are computed using a Bayesian model averaging method, and are validated for DES data using simulations and COSMOS data. We show that μ_⋆ works as a promising mass proxy by comparing our predictions to X-ray measurements. We measure the X-ray temperature–μ_⋆ relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 < |$z$| < 0.7. For a scaling relation that is linear in logarithmic space, we find a slope of α = 0.488 ± 0.043 and a scatter in the X-ray temperature at fixed μ_⋆ of |$\sigma _{{\rm ln} T_\mathrm{ X}|\mu _\star }= 0.266^{+0.019}_{-0.020}$| for the joint sample. By using the halo mass scaling relations of the X-ray temperature from the Weighing the Giants program, we further derive the μ_⋆-conditioned scatter in mass, finding |$\sigma _{{\rm ln} M|\mu _\star }= 0.26^{+ 0.15}_{- 0.10}$|⁠. These results are competitive with well-established cluster mass proxies used for cosmological analyses, showing that μ_⋆ can be used as a reliable and physically motivated mass proxy to derive cosmological constraints.

Using archival X-ray observations and a lognormal population model, we estimate constraints on the intrinsic scatter in halo mass at fixed optical richness for a galaxy cluster sample identified in Dark Energy Survey Year-One (DES-Y1) data with the redMaPPer algorithm. We examine the scaling behaviour of X-ray temperatures, T_X, with optical richness, λ_RM, for clusters in the redshift range 0.2 < z < 0.7. X-ray temperatures are obtained from Chandra and XMM observations for 58 and 110 redMaPPer systems, respectively. Despite non-uniform sky coverage, the measurements are |$\gt 50{{\ \rm per\ cent}}$| complete for clusters with λ_RM > 130. Regression analysis on the two samples produces consistent posterior scaling parameters, from which we derive a combined constraint on the residual scatter, |$\sigma _{\ln T \, |\, \lambda }= 0.275 \pm 0.019$|⁠. Joined with constraints for T_X scaling with halo mass from the Weighing the Giants program and richness–temperature covariance estimates from the LoCuSS sample, we derive the richness-conditioned scatter in mass, |$\sigma _{\ln M \, |\, \lambda }= 0.30 \pm 0.04\, _{({\rm stat})} \pm 0.09\, _{({\rm sys})}$|⁠, at an optical richness of approximately 100. Uncertainties in external parameters, particularly the slope and variance of the T_X–mass relation and the covariance of T_X and λ_RM at fixed mass, dominate the systematic error. The |$95{{\ \rm per\ cent}}$| confidence region from joint sample analysis is relatively broad, |$\sigma _{\ln M \, |\, \lambda }\in [0.14, \, 0.55]$|⁠, or a factor 10 in variance.

In a shallow near-infrared survey of the dwarf irregular galaxy, NGC 3109, near the periphery of the Local Group, we have found eight Mira variables, seven of which appear to be oxygen-rich (O-Miras). The periods range from about 430 d to almost 1500 d. Because of our relatively bright limiting magnitude, only 45 of the more than 400 known carbon stars were measured, but none was found to be a large amplitude variable. One of the Miras may be an unrecognized C star. Five of the O-Miras are probably hot-bottom burning stars considering that they are brighter than expected from the period-luminosity relation of Miras and that, by comparison with theoretical evolutionary tracks, they appear to have masses {≳}4 M_⊙. A census of very long period (P > 1000 d) Miras in the Galaxy and Magellanic Clouds is presented and discussed together with the newly discovered long-period, but relatively blue, variables in NGC 3109. New JHKL photometry is presented for three O-rich long-period Miras in the Small Magellanic Cloud (including a candidate super-AGB star).

We present a spatially resolved study of the relation between dust and metallicity in the nearby spiral galaxies M 101 (NGC 5457) and NGC 628 (M 74). We explore the relation between the chemical abundances of their gas and stars with their dust content and their chemical evolution. The empirical spatially resolved oxygen effective yield and the gas-to-dust mass ratio (GDR) across both disc galaxies are derived, sampling 1 dex in oxygen abundance. We find that the metal budget of the NGC 628 disc and most of the M 101 disc appears consistent with the predictions of the simple model of chemical evolution for an oxygen yield between half and one solar, whereas the outermost region (R ≥ 0.8 R_{25}) of M 101 presents deviations suggesting the presence of gas flows. The GDR-metallicity relation shows a two slopes behaviour, with a break at 12 + log(O/H) ≈ 8.4, a critical metallicity predicted by theoretical dust models when stardust production equals grain growth. A relation between GDR and the fraction of molecular to total gas, Σ _{H₂}/Σ _{gas} is also found. We suggest an empirical relationship between GDR and the combination of 12 + log(O/H), for metallicity, and Σ _{H₂}/Σ _{gas}, a proxy for the molecular clouds fraction. The GDR is closely related with metallicity at low abundance and with Σ _{H₂}/Σ _{gas} for higher metallicities suggesting interstellar medium dust growth. The ratio Σ _{dust}/Σ _{star} correlates well with 12 + log(O/H) and strongly with log(N/O) in both galaxies. For abundances below the critical one, the `stardust' production gives us a constant value suggesting a stellar dust yield similar to the oxygen yield.

We report on a superdense star-forming region with an effective radius (R_e) smaller than 13 pc identified at z = 6.143 and showing a star formation rate density Σ_SFR ∼ 1000 M_⊙ yr^-1 kpc^-2 (or conservatively >300 M_⊙ yr^-1 kpc^-2). Such a dense region is detected with S/N ≳ 40 hosted by a dwarf extending over 440 pc, dubbed D1. D1 is magnified by a factor 17.4(±5.0) behind the Hubble Frontier Field galaxy cluster MACS J0416 and elongated tangentially by a factor 13.2 ± 4.0 (including the systematic errors). The lens model accurately reproduces the positions of the confirmed multiple images with a rms of 0.35 arcsec. D1 is part of an interacting star-forming complex extending over 800 pc. The SED-fitting, the very blue ultraviolet slope (β ≃ -2.5, F_λ ∼ λ^β), and the prominent Lyα emission of the stellar complex imply that very young (<10-100 Myr), moderately dust-attenuated (E(B - V) < 0.15) stellar populations are present and organized in dense subcomponents. We argue that D1 (with a stellar mass of 2 × 10⁷ M_⊙) might contain a young massive star cluster of M ≲ 10⁶ M_⊙ and M_UV ≃ -15.6 (or m_UV = 31.1), confined within a region of 13 pc, and not dissimilar from some local super star clusters (SSCs). The ultraviolet appearance of D1 is also consistent with a simulated local dwarf hosting an SSC placed at z = 6 and lensed back to the observer. This compact system fits into some popular globular cluster formation scenarios. We show that future high spatial resolution imaging (e.g. E-ELT/MAORY-MICADO and VLT/MAVIS) will allow us to spatially resolve light profiles of 2-8 pc.

We present an implementation of the relativistic three-particle quantization condition including both s- and d-wave two-particle channels. For this, we develop a systematic expansion of the three-particle K matrix, K _df,3, about threshold, which is the generalization of the effective range expansion of the two-particle K matrix, K ₂. Relativistic invariance plays an important role in this expansion. We find that d-wave two-particle channels enter first at quadratic order. We explain how to implement the resulting multichannel quantization condition, and present several examples of its application. We derive the leading dependence of the threshold three-particle state on the two-particle d-wave scattering amplitude, and use this to test our implementation. We show how strong two-particle d-wave interactions can lead to significant effects on the finite-volume three-particle spectrum, including the possibility of a generalized three-particle Efimov-like bound state. We also explore the application to the 3 π ⁺ system, which is accessible to lattice QCD simulations, where we study the sensitivity of the spectrum to the components of K _df,3. Finally, we investigate the circumstances under which the quantization condition has unphysical solutions.

High-energy radiation from a planet host star can have strong influence on the final habitability of a system through several mechanisms. In this context we have constructed a catalogue containing the X-ray luminosities, as well as basic stellar and planetary properties of all known stars hosting giant planets (> 0.1 M_J) that have been observed by the Chandra X-ray Observatory, XMM-Newton, and/or ROSAT. Specifically in this paper we present a first application of this catalogue to search for a possible imprint of X-ray photoevaporation of planet-forming discs on the present-day orbital distribution of the observed giant planets. We found a suggestive void in the semimajor axis, a, versus X-ray luminosity, L_x, plane, roughly located between a ∼ 0.05-1 au and L_x ∼ 10²⁷-10^{29} erg s^{-1}, which would be expected if photoevaporation played a dominant role in the migration history of these systems. However, due to the small observational sample size, the statistical significance of this feature cannot be proven at this point.

We propose an expression for a local planetesimal formation rate proportional to the instantaneous radial pebble flux. The result—a radial planetesimal distribution—can be used as an initial condition to study the formation of planetary embryos. We follow the idea that one needs particle traps to locally enhance the dust-to-gas ratios sufficiently, such that particle gas interactions can no longer prevent planetesimal formation on small scales. The locations of these traps can emerge everywhere in the disk. Their occurrence and lifetime is subject to ongoing research; thus, here they are implemented via free parameters. This enables us to study the influence of the disk properties on the formation of planetesimals, predicting their time-dependent formation rates and the location of primary pebble accretion. We show that large α-values of 0.01 (strong turbulence) prevent the formation of planetesimals in the inner part of the disk, arguing for lower values of around 0.001 (moderate turbulence), at which planetesimals form quickly at all places where they are needed for proto-planets. Planetesimals form as soon as dust has grown to pebbles (mm to dm) and the pebble flux reaches a critical value, which is after a few thousand years at 2-3 au and after a few hundred thousand years at 20-30 au. Planetesimal formation lasts until the pebble supply has decreased below a critical value. The final spatial planetesimal distribution is steeper compared to the initial dust and gas distribution, which helps explain the discrepancy between the minimum mass solar nebula and viscous accretion disks.

In the presence of a relative suppression of the different quarkonium states and due to the feed downs, the statement on pg. 1 & 2 "one is entitled […] to square the measured suppression factor [12] in pPb collisions to extrapolate to PbPb collisions."

Context. Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important classes of variable stars used as standard candles to estimate galactic and extragalactic distances. Their multiplicity is imperfectly known, particularly for RRLs. Astoundingly, to date only one RRL has convincingly been demonstrated to be a binary, TU UMa, out of tens of thousands of known RRLs.
Aims: Our aim is to detect the binary and multiple stars present in a sample of Milky Way CCs and RRLs.
Methods: In the present article, we combine the HIPPARCOS and Gaia DR2 positions to determine the mean proper motion of the targets, and we search for proper motion anomalies (PMa) caused by close-in orbiting companions.
Results: We identify 57 CC binaries from PMa out of 254 tested stars and 75 additional candidates, confirming the high binary fraction of these massive stars. For 28 binary CCs, we determine the companion mass by combining their spectroscopic orbital parameters and astrometric PMa. We detect 13 RRLs showing a significant PMa out of 198 tested stars, and 61 additional candidates.
Conclusions: We determine that the binary fraction of CCs is likely above 80%, while that of RRLs is at least 7%. The newly detected systems will be useful to improve our understanding of their evolutionary states. The discovery of a significant number of RRLs in binary systems also resolves the long-standing mystery of their extremely low apparent binary fraction.

Full Tables A.1 and A.3 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/qcat?J/A+A/623/A116

Context. The multiplicity of classical Cepheids (CCs) and RR Lyrae stars (RRLs) is still imperfectly known, particularly for RRLs.
Aims: In order to complement the close-in short orbital period systems presented in Paper I, our aim is to detect the wide, spatially resolved companions of the targets of our reference samples of Galactic CCs and RRLs.
Methods: Angularly resolved common proper motion pairs were detected using a simple progressive selection algorithm to separate the most probable candidate companions from the unrelated field stars.
Results: We found 27 resolved, high probability gravitationally bound systems with CCs out of 456 examined stars, and one unbound star embedded in the circumstellar dusty nebula of the long-period Cepheid RS Pup. We found seven spatially resolved, probably bound systems with RRL primaries out of 789 investigated stars, and 22 additional candidate pairs. We report in particular new companions of three bright RRLs: OV And (companion of F4V spectral type), RR Leo (M0V), and SS Oct (K2V). In addition, we discovered resolved companions of 14 stars that were likely misclassified as RRLs.
Conclusions: The detection of resolved non-variable companions around CCs and RRLs facilitates the validation of their Gaia DR2 parallaxes. The possibility to conduct a detailed analysis of the resolved coeval companions of CCs and old population RRLs will also be valuable to progress on our understanding of their evolutionary path.

Tables A.1-C.1 are also 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/qcat?J/A+A/623/A117

Aims: The characterisation of galaxy-scale outflows in terms of their multi-phase and multi-scale nature, amount, and effects of flowing material is crucial to place constraints on models of galaxy formation and evolution. This study can proceed only with the detailed investigation of individual targets.
Methods: We present a spatially resolved spectroscopic optical data analysis of Mkn 848, a complex system consisting of two merging galaxies at z ∼ 0.04 that are separated by a projected distance of 7.5 kpc. Motivated by the presence of a multi-phase outflow in the north-west system revealed by the SDSS integrated spectrum, we analysed the publicly available MaNGA data, which cover almost the entire merging system, to study the kinematic and physical properties of cool and warm gas in detail.
Results: Galaxy-wide outflowing gas in multiple phases is revealed for the first time in the two merging galaxies. We also detect spatially resolved resonant Na ID emission associated with the outflows. The derived outflow energetics (mass rate, and kinetic and momentum power) may be consistent with a scenario in which both winds are accelerated by stellar processes and AGN activity, although we favour an AGN origin given the high outflow velocities and the ionisation conditions observed in the outflow regions. Further deeper multi-wavelength observations are required, however, to better constrain the nature of these multi-phase outflows. Outflow energetics in the North-West system are strongly different between the ionised and atomic gas components, the latter of which is associated with mass outflow rate and kinetic and momentum powers that are one or two dex higher; those associated with the south-east galaxy are instead similar.
Conclusions: Strong kiloparsec-scale outflows are revealed in an ongoing merger system, suggesting that feedback can potentially impact the host galaxy even in the early merger phases. The characterisation of the neutral and ionised gas phases has proved to be crucial for a comprehensive study of the outflow phenomena.

A copy of the reduced datacube is also 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/qcat?J/A+A/623/A171

A compact device lifted over the ground surface might be used to observe optical radiation of extensive air showers (EAS). Here we consider spatial and temporal characteristics of Vavilov-Cherenkov radiation ("Cherenkov light") reflected from the snow surface of Lake Baikal, as registered by the SPHERE-2 detector. We perform detailed full direct Monte Carlo simulations of EAS development and present a dedicated highly modular code intended for detector response simulations. Detector response properties are illustrated by example of several model EAS events. The instrumental acceptance of the SPHERE-2 detector was calculated for a range of observation conditions. We introduce the concept of "composite model quantities", calculated for detector responses averaged over photoelectron count fluctuations, but retaining EAS development fluctuations. The distortions of EAS Cherenkov light lateral distribution function (LDF) introduced by the SPHERE-2 telescope are understood by comparing composite model LDF with the corresponding function as would be recorded by an ideal detector situated at the ground surface. We show that the uncertainty of snow optical properties does not change our conclusions, and, moreover, that the expected performance of the SPHERE experiment in the task of cosmic ray mass composition study in the energy region ∼ 10 PeV is comparable with other contemporary experiments. Finally, we compare the reflected Cherenkov light method with other experimental techniques and briefly discuss its prospects.

We modify the usual definitions of cumulants of net-charge fluctuations in a way that isolates dynamical fluctuations. The new observables, which we call dynamical cumulants, are robust with respect to trivial correlations induced by volume fluctuations and global charge conservation. We illustrate the potential of dynamical cumulants by carrying out Monte Carlo simulations where all correlations are trivial. The results of our simulations agree well with BNL Relativistic Heavy Ion Collider (RHIC) data, and are used to illustrate that dynamical cumulants consistently isolate dynamical fluctuations.

Parton shower event generators typically approximate evolution of QCD color so that only contributions that are leading in the limit of an infinite number of colors are retained. Our parton shower generator, Deductor, has used an "LC+" approximation that is better, but still quite limited. In this paper, we introduce a new scheme for color in which the approximations can be systematically improved. That is, one can choose the theoretical accuracy level, but the accuracy level that is practical is limited by the computer resources available.

In the era of precision cosmology, it is essential to determine the Hubble constant empirically with an accuracy of one per cent or better¹. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period-luminosity relationship^2,3 (also known as the Leavitt law). The Large Magellanic Cloud has traditionally served as the best galaxy with which to calibrate Cepheid period-luminosity relations, and as a result has become the best anchor point for the cosmic distance scale^4,5. Eclipsing binary systems composed of late-type stars offer the most precise and accurate way to measure the distance to the Large Magellanic Cloud. Currently the limit of the precision attainable with this technique is about two per cent, and is set by the precision of the existing calibrations of the surface brightness-colour relation^5,6. Here we report a calibration of the surface brightness-colour relation with a precision of 0.8 per cent. We use this calibration to determine a geometrical distance to the Large Magellanic Cloud that is precise to 1 per cent based on 20 eclipsing binary systems. The final distance is 49.59 ± 0.09 (statistical) ± 0.54 (systematic) kiloparsecs.

Dwarf galaxies are ideal laboratories to study the physics of the interstellar medium (ISM). Emission lines have been widely used to this aim. Retrieving the full information encoded in the spectra is therefore essential. This can be efficiently and reliably done using Machine Learning (ML) algorithms. Here, we apply the ML code GAME to MUSE (Multi Unit Spectroscopic Explorer) and PMAS (Potsdam Multi Aperture Spectrophotometer) integral field unit observations of two nearby blue compact galaxies: Henize 2-10 and IZw18. We derive spatially resolved maps of several key ISM physical properties. We find that both galaxies show a remarkably uniform metallicity distribution. Henize 2-10 is a star-forming-dominated galaxy, with a star formation rate (SFR) of about 1.2 M_⊙ yr^-1. Henize 2-10 features dense and dusty (A_V up to 5-7 mag) star-forming central sites. We find IZw18 to be very metal-poor (Z = 1/20 Z_⊙). IZw18 has a strong interstellar radiation field, with a large ionization parameter. We also use models of PopIII stars spectral energy distribution as a possible ionizing source for the He II λ4686 emission detected in the IZw18 NW component. We find that PopIII stars could provide a significant contribution to the line intensity. The upper limit to the PopIII star formation is 52 per cent of the total IZw18 SFR.

We compute the master integrals required for the calculation of the double-real emission contributions to the matching coefficients of 0-jettiness beam functions at nextto-next-to-next-to-leading order in perturbative QCD. As an application, we combine these integrals and derive the double-real gluon emission contribution to the matching coefficient I _qq ( t, z) of the quark beam function.

We present a resummation of the non-global and clustering effects in groomed (with modified mass drop tagger) multi-pronged observables, valid to next-to leading logarithmic accuracy in the D ₂ distribution (all single logarithmic terms), focusing on the non-global and clustering effects which cannot be removed by normalizing the cross-section. These effects are universal in the sense that they depend only on the flavor structure of the 1 → 2 splitting forming the multi-pronged subjets and the opening angle of the splitting, being insensitive to the underlying hard process or underlying event. The differential spectra with and without the non-global and clustering effects are presented, and the change in the spectra is found to be small.

Hydrodynamic instabilities in disks around young stars depend on the thermodynamic stratification of the disk and on the local rate of thermal relaxation. Here, we map the spatial extent of unstable regions for the Vertical Shear Instability (VSI), the Convective Overstability (COS), and the amplification of vortices via the Subcritical Baroclinic Instability (SBI). We use steady-state accretion disk models, including stellar irradiation, accretion heating, and radiative transfer. We determine the local radial and vertical stratification and thermal relaxation rate in the disk, which depends on the stellar mass, disk mass, and mass accretion rate. We find that passive regions of disks—that is, the midplane temperature dominated by irradiation—are COS unstable about one pressure scale height above the midplane and VSI unstable at radii >10 au. Vortex amplification via SBI should operate in most parts of active and passive disks. For active parts of disks (midplane temperature determined by accretion power), COS can become active down to the midplane. The same is true for the VSI because of the vertically adiabatic stratification of an internally heated disk. If hydrodynamic instabilities or other nonideal MHD processes are able to create α-stresses (>10^-5) and released accretion energy leads to internal heating of the disk, hydrodynamic instabilities are likely to operate in significant parts of the planet-forming zones in disks around young stars, driving gas accretion and flow structure formation. Thus, hydrodynamic instabilities are viable candidates to explain the rings and vortices observed with the Atacama Large Millimeter/submillimeter Array and Very Large Telescope.

In this paper JK_s-band data from the VISTA Magellanic Cloud (VMC) survey are used to investigate the tip of the red giant branch (TRGB) as a distance indicator. A linear fit to recent theoretical models is used as the basis for the absolute calibration which reads M_Ks = -4.196 - 2.013 (J - K_s), valid in the colour range 0.75 < (J - K_s)< 1.3 mag and in the 2MASS system. The observed TRGB is found based on a classical first-order derivative filter and a second-order derivative filter applied to the binned luminosity function using the "sharpened" magnitude that takes the colour term into account. Extensive simulations are carried out to investigate any biases and errors in the derived distance modulus (DM). Based on these simulations criteria are established related to the number of stars per bin in the 0.5 mag range below the TRGB and related to the significance with which the peak in the filter response curve is determined such that the derived distances are unbiased. The DMs based on the second-order derivative filter are found to be more stable and are therefore adopted, although this requires twice as many stars per bin. Given the surface density of TRGB stars in the Magellanic Clouds (MCs), areas of ∼0.5 deg² in the densest parts to ∼10 deg² in the outskirts of the MCs need to be considered to obtain accurate and reliable values for the DMs. The TRGB method is applied to specific lines-of-sight where independent distance estimates exist, based on detached eclipsing binaries in the Large and Small Magellanic Clouds (LMC, SMC), classical Cepheids in the LMC, RR Lyrae stars in the SMC, and fields in the SMC where the star formation history (together with reddening and distance) has been derived from deep VMC data. The analysis shows that the theoretical calibration is consistent with the data, that the systematic error on the DM is approximately 0.045 mag (about evenly split between the theoretical calibration and the method), and that random errors of 0.015 mag are achievable. Reddening is an important element in deriving the distance: we derive mean DMs ranging from 18.92 mag (for a typical E(B - V) of 0.15 mag) to 19.07 mag (E(B - V)∼0.04 mag) for the SMC, and ranging from 18.48 mag (E(B - V)∼0.12 mag) to 18.57 mag (E(B - V)∼0.05 mag) for the LMC.

Based on observations made with VISTA at ESO under programme ID 179.B-2003.

A permanent electric dipole moment (EDM) of a particle or system is a separation of charge along its angular momentum axis and is a direct signal of T violation and, assuming C P T symmetry, C P violation. For over 60 years EDMs have been studied, first as a signal of a parity-symmetry violation and then as a signal of C P violation that would clarify its role in nature and in theory. Contemporary motivations include the role that C P violation plays in explaining the cosmological matter-antimatter asymmetry and the search for new physics. Experiments on a variety of systems have become ever-more sensitive, but provide only upper limits on EDMs, and theory at several scales is crucial to interpret these limits. Nuclear theory provides connections from standard-model and beyond-standard-model physics to the observable EDMs, and atomic and molecular theory reveal how C P violation is manifest in these systems. EDM results in hadronic systems require that the standard-model QCD parameter of θ ¯ must be exceptionally small, which could be explained by the existence of axions, also a candidate dark-matter particle. Theoretical results on electroweak baryogenesis show that new physics is needed to explain the dominance of matter in the Universe. Experimental and theoretical efforts continue to expand with new ideas and new questions, and this review provides a broad overview of theoretical motivations and interpretations as well as details about experimental techniques, experiments, and prospects. The intent is to provide specifics and context as this exciting field moves forward.

Indications from Gaia data release 2 are that the tip of the red giant branch (a population II standard candle related to the helium flash in low mass stars) is close to -4 in absolute I magnitude in the Cousins photometric system. Our sample is high-latitude southern stars from the thick disk and inner halo, and our result is consistent with longstanding findings from globular clusters, whose distances were calibrated with RR Lyrae stars. As the Gaia mission proceeds, there is every reason to think an accurate Galactic geometric calibration of tip of the red giant branch will be a significant outcome for the extragalactic distance scale.

Numerous superluminous supernovae (SLSNe) of Type Ic have been discovered and monitored in the last decade. The favored mechanism at their origin is a sustained power injection from a magnetar. This study presents non-local thermodynamic equilibrium (NLTE) time-dependent radiative transfer simulations of various single carbon-rich Wolf-Rayet star explosions influenced by magnetars of diverse properties and covering from a few days to one or two years after explosion. Nonthermal processes are treated; the magnetar-power deposition profile is prescribed; dynamical effects are ignored. In this context, the main influence of the magnetar power is to boost the internal energy of the ejecta on week-long time scales, enhancing the ejecta temperature and ionization, shifting the spectral energy distribution to the near-UV (even for the adopted solar metallicity), creating blue optical colors. Varying the ejecta and magnetar properties introduces various stretches and shifts to the light curve (rise time, peak or nebular luminosity, light curve width). At maximum, all models show the presence of O II and C II lines in the optical, and more rarely O III and C III lines. Non-thermal effects are found to be negligible during the high-brightness phase. After maximum, higher energy explosions are hotter and more ionized, and produce spectra that are optically bluer. Clumping is a source of spectral diversity after maximum. Clumping is essential to trigger ejecta recombination and yield the presence of O I, Ca II, and Fe II lines from a few weeks after maximum until nebular times. The UV and optical spectrum of Gaia16apd at maximum or the nebular spectrum of LSQ14an at +410 d are compatible with some models that assume no clumping. However, most observed SLSNe Ic seem to require clumping from early post-maximum to nebular times (e.g., SN 2007bi at +46 and +367 d; Gaia16apd at +43 d).

We review some of the common methods for model selection: the goodness of fit, the likelihood ratio test, Bayesian model selection using Bayes factors, and the classical as well as the Bayesian information theoretic approaches. We illustrate these different approaches by comparing models for the expansion history of the Universe. In the discussion we highlight the premises and objectives entering these different approaches to model selection and finally recommend the information theoretic approach.

A critical review of the standard paradigm for the origin of Galactic cosmic rays (CRs) is presented. Recent measurements of local and far-away CRs reveal unexpected behaviors, which challenge the commonly accepted scenario. These recent findings are discussed, together with long-standing open issues. Despite the progress made thanks to ever-improving observational techniques and theoretical investigations, at present our understanding of the origin and of the behavior of CRs remains incomplete. We believe it is still unclear whether a modification of the standard paradigm, or rather a radical change of the paradigm itself is needed in order to interpret all the available data on CRs within a self-consistent scenario.

Different types of core-collapse supernovae (SNe) have been considered as candidate sources of high-energy cosmic neutrinos. Stripped-envelope SNe, including energetic events like hypernovae and super-luminous SNe, are of particular interest. They may harbor relativistic jets, which are capable of explaining the diversity among gamma-ray bursts (GRBs), low-luminosity GRBs, ultra-long GRBs, and broadline Type Ib/c SNe. Using the six-year IceCube data on high-energy starting events (HESEs), we perform an unbinned maximum likelihood analysis to search for spatial and temporal coincidences with 222 samples of SNe Ib/c. We find that the present data are consistent with the background only hypothesis, by which we place new upper constraints on the isotropic-equivalent energy of cosmic rays, Script E_crlesssim10⁵² erg, in the limit that all SNe are accompanied by on-axis jets. Our results demonstrate that not only upgoing muon neutrinos but also HESE data enable us to constrain the potential contribution of these SNe to the diffuse neutrino flux observed in IceCube. We also discuss implications for the next-generation neutrino detectors such as IceCube-Gen2 and KM3Net.

The theoretical interpretation of dark matter (DM) experiments is hindered by uncertainties on the dark matter density and velocity distribution inside the Solar System. In order to quantify those uncertainties, we present a parameter that characterizes the deviation of the true velocity distribution from the standard Maxwell-Boltzmann form, and we then determine for different values of this parameter the most aggressive and most conservative limits on the dark matter scattering cross section with nuclei; uncertainties in the local dark matter density can be accounted for trivially. This allows us to bracket, in a model independent way, the impact of astrophysical uncertainties on limits from direct detection experiments and/or neutrino telescopes. We find that current limits assuming the Standard Halo Model are at most a factor of ~ 2 weaker than the most aggressive possible constraints. In addition, combining neutrino telescope and direct detection constraints (in a statistically meaningful way), we show that limits on DM in the mass range ~ 10 - 1000 GeV cannot be weakened by more than around a factor of 10, for all possible velocity distributions. We finally demonstrate that our approach can also be employed in the event of a DM discovery, allowing us to avoid bias in the reconstruction of the DM properties.

Parton distribution functions are key quantities for us to understand the hadronic structures in high-energy scattering, but they are difficult to calculate from lattice QCD. Recent years have seen fast development of the large-momentum effective theory which allows extraction of the x-dependence of parton distribution functions from a quasi-parton distribution function that can be directly calculated on lattice. The extraction is based on a factorization formula for the quasi-parton distribution function that has been derived rigorously in perturbation theory. A systematic procedure that includes renormalization, perturbative matching, and power corrections has been established to calculate parton distribution functions. Latest progress from lattice QCD has shown promising signs that it will become an effective tool for calculating parton physics.

In the large top-mass limit, Higgs plus multi-gluon amplitudes in QCD can be computed using an effective field theory. This approach turns the computation of such amplitudes into that of form factors of operators of increasing classical dimension. In this paper we focus on the first finite top-mass correction, arising from the operator Tr( F ³), up to two loops and three gluons. Setting up the calculation in the maximally supersymmetric theory requires identification of an appropriate supersymmetric completion of Tr( F ³), which we recognise as a descendant of the Konishi operator. We provide detailed computations for both this operator and the component operator Tr( F ³), preparing the ground for the calculation in N < 4, to be detailed in a companion paper. Our results for both operators are expressed in terms of a few universal functions of transcendental degree four and below, some of which have appeared in other contexts, hinting at universality of such quantities. An important feature of the result is a delicate cancellation of unphysical poles appearing in soft/collinear limits of the remainders which links terms of different transcendentality. Our calculation provides another example of the principle of maximal transcendentality for observables with non-trivial kinematic dependence.

We present a detailed light-curve analysis of RR Lyrae variables at multiple wavelengths using Fourier decomposition method. The time-series data for RR Lyrae variables in the Galactic bulge and the Magellanic Clouds are taken from the Optical Gravitational Lensing Experiment survey while the infrared light curves are compiled from the literature. We also analyse the multiband theoretical light curves that are generated from the stellar pulsation models of RR Lyrae stars for a wide range of metal abundances. We find that the theoretical light-curve parameters with different metal abundances are consistent with observed parameters in most period bins at both optical and infrared wavelengths. The theoretical and observed Fourier amplitude parameters decrease with increase in wavelength while the Fourier phase parameters increase with wavelength at a given period. We use absolute magnitudes for a subset of theoretical models that fit the observed optical RR Lyrae light curves in the Large Magellanic Cloud to estimate a distance modulus, μ_LMC = 18.51 ± 0.07, independent of the metallicity. We also use Fourier analysis to study the period-colour and amplitude-colour relations for RR Lyrae stars in the Magellanic Clouds using optical data and find that the slope of period-colour relation at minimum light is very shallow or flat and becomes increasingly significant at the maximum light for RRab stars. We also find that the metallicity dependence of the period-colour relations increases as we go from minimum to maximum light, suggesting that the mean light results are indeed an average of the various pulsational phases. We summarize that the average variation in these relations is consistent between theory and observations and supports the theory of the interaction of the stellar photosphere and the hydrogen ionization front.

Galaxy formation is at the heart of our understanding of cosmic evolution. Although there is a consensus that galaxies emerged from the expanding matter background by gravitational instability of primordial fluctuations, a number of additional physical processes must be understood and implemented in theoretical models before these can be reliably used to interpret observations. In parallel, the astonishing recent progresses made in detecting galaxies that formed only a few hundreds of million years after the Big Bang is pushing the quest for more sophisticated and detailed studies of early structures. In this review, we combine the information gleaned from different theoretical models/studies to build a coherent picture of the Universe in its early stages which includes the physics of galaxy formation along with the impact that early structures had on large-scale processes as cosmic reionization and metal enrichment of the intergalactic medium.

High-resolution Atacama Large Millimeter/submillimeter Array observations of protoplanetary disks have revealed that many, if not all, primordial disks consist of ring-like dust structures. The origin of these dust rings remains unclear, but a common explanation is the presence of planetary companions that have cleared gaps along their orbit and trapped the dust at the gap edge. A signature of this scenario is a decrease of gas density inside these gaps. In a recent work, Isella et al. derived drops in gas density that are consistent with Saturn-mass planets inside the gaps in the HD 163296 disk through spatially resolved CO isotopologue observations. However, as CO abundance and temperature depends on a large range of factors, the interpretation of CO emission is non-trivial. We use the physical-chemical code DALI to show that the gas temperature increases inside dust density gaps, implying that any gaps in the gas, if present, would have to be much deeper, consistent with planet masses >M _Jup. Furthermore, we show that a model with increased grain growth at certain radii, as expected at a snowline, can reproduce the dust rings in HD 163296 equally well without the need for companions. This scenario can explain both younger and older disks with observed gaps, as gaps have been seen in systems as young <1 Myr. While the origin of the rings in HD 163296 remains unclear, these modeling results demonstrate that care has to be taken when interpreting CO emission in protoplanetary disk observations.

Aims: The standard active galactic nuclei (AGN)-galaxy co-evolutionary scenario predicts a phase of deeply "buried" supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous quasar (QSO) is revealed (called the SB-QSO evolutionary sequence). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of submillimetre galaxies (SMGs), as expected by some models, and to place these measurements in the context of the SB-QSO framework.
Methods: We target CO(1-0) transition in BzK4892, a Compton thick (CT) QSO at z = 2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured (N_H ≈ 6 × 10²³ cm^-2) QSOs at z = 2.5 and z = 1.5, respectively. For these targets, we place 3σ upper limits on the CO lines, with L'_CO < (1.5 ÷ 2.8)×10¹⁰ K km s^-1 pc². We also compare the molecular gas conditions of our targets with those of other systems at z > 1, considering normal star-forming galaxies and SMGs, and unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and almost complete collection of targets with CO follow-up at z > 1.
Results: BzK4892 displays a high star formation efficiency (SFE = L_IR/L'_CO > 410 L_⊙/(K km s^-1 pc² )) and a gas fraction f_gas = M_gas/(M_star + M_gas)< 10%. Less stringent constraints are derived for the other two targets (f_gas < 0.5 and SFE > 10 L_⊙/(K km s^-1 pc² )). From the comparison with the literature data we found that, on average, i) obscured AGN at z > 1 are associated with higher SFE and lower f_gas with respect to normal star-forming galaxies and SMGs; ii) mildly and highly obscured active galaxies have comparable gas fractions; iii) the SFE of CT and obscured AGN are similar to those of unobscured AGN.
Conclusions: Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO evolutionary sequence.

Distant luminous Lyman-α emitters (LAEs) are excellent targets for spectroscopic observations of galaxies in the epoch of reionisation (EoR). We present deep high-resolution (R = 5000) VLT/X-shooter observations, along with an extensive collection of photometric data of COLA1, a proposed double peaked LAE at z = 6.6. We rule out the possibility that COLA1's emission line is an [OII] doublet at z = 1.475 on the basis of i) the asymmetric red line-profile and flux ratio of the peaks (blue/red=0.31 ± 0.03) and ii) an unphysical [OII]/Hα ratio ([OII]/Hα > 22). We show that COLA1's observed B-band flux is explained by a faint extended foreground LAE, for which we detect Lyα and [OIII] at z = 2.142. We thus conclude that COLA1 is a real double-peaked LAE at z = 6.593, the first discovered at z > 6. COLA1 is UV luminous (M₁₅₀₀ = -21.6 ± 0.3), has a high equivalent width (EW_0,Lyα = 120_-40⁺⁵⁰ Å) and very compact Lyα emission (r_50,Lyα = 0.33_-0.04^+0.07 kpc). Relatively weak inferred Hβ+[OIII] line-emission from Spitzer/IRAC indicates an extremely low metallicity of Z < 1/20 Z_⊙ or reduced strength of nebular lines due to high escape of ionising photons. The small Lyα peak separation of 220 ± 20 km s^-1 implies a low HI column density and an ionising photon escape fraction of ≈15 - 30%, providing the first direct evidence that such galaxies contribute actively to the reionisation of the Universe at z > 6. Based on simple estimates, we find that COLA1 could have provided just enough photons to reionise its own ≈0.3 pMpc (2.3 cMpc) bubble, allowing the blue Lyα line to be observed. However, we also discuss alternative scenarios explaining the detected double peaked nature of COLA1. Our results show that future high-resolution observations of statistical samples of double peaked LAEs at z > 5 are a promising probe of the occurrence of ionised regions around galaxies in the EoR.

Based on observations obtained with the Very Large Telescope, programs: 294.A-5039, 099.A-0254 and 100.A-0213.Reduced 1D X-shooter spectrum is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/619/A136

Recent observations with the Atacama Large Millimeter/submillimeter Array (ALMA) detected far-infrared emission lines such as the [O III] 88 μ m line from galaxies at z ∼ 7-9. We use a cosmological simulation of galaxy formation to study the physical properties of [O III] 88 μ m emitters. In a comoving volume of 50 h^-1 Mpc on a side, we locate 34 galaxies with stellar masses greater than 10^8 M_{⊙} at z = 9, and more than 270 such galaxies at z = 7. We calculate the [O III] 88 μ m luminosities (L_{O III}, 88) by combining a physical model of H II regions with emission line calculations using the photoionization code CLOUDY. We show that the resulting L_{O III}, 88, for a given star formation rate, is slightly higher than predicted from the empirical relation for local galaxies, and is consistent with recent observations of galaxies at redshifts 7-9. Bright [O III] emitters with L_{O III}, 88 > 10^8 L_{⊙} have star formation rates higher than 3 M_{⊙} yr^{-1}, and the typical metallicity is {∼ } 0.1 Z_{⊙}. The galaxies are hosted by dark matter haloes with masses greater than 10^{11} M_{⊙}. We propose to use the [O III] 5007 Å line, to be detected by James Webb Space Telescope, to study the properties of galaxies whose [O III] 88 μ m line emission has been already detected with ALMA.

Predictions are made for elliptic flow in collisions of polarized deuterons with a heavy nucleus. It is shown that the eccentricity of the initial fireball, evaluated with respect to the deuteron polarization axis perpendicular to the beam direction, has a substantial magnitude for collisions of highest multiplicity. Within the Glauber approach we obtain ∼7 % for the deuteron states with spin projection 0, and ∼-3 % for spin projection ±1 . We propose to measure the elliptic flow coefficient as the second order harmonic coefficient in the azimuthal distribution of produced charged hadrons with respect to the fixed polarization axis. Collective expansion yields a value of the order of 1% for this quantity, as compared to zero in the absence of polarization and/or collectivity. Such a vivid rotational symmetry breaking could be measured with the current experimental accuracy of the relativistic heavy-ion experiments. The effect has a fundamental significance for understanding the nature of dynamics in small systems, as its experimental confirmation would prove the presence of the shape-flow transmutation mechanism, typical of hydrodynamic expansion or rescattering in the later stages of the fireball evolution.

We present compact integral representations for the calculation of two-loop anomalous dimensions for a generic class of soft functions that are defined in terms of two light-like Wilson lines. Our results are relevant for the resummation of Sudakov logarithms for e⁺e^- event-shape variables and inclusive hadron-collider observables at next-to-next-to-leading logarithmic accuracy within Soft-Collinear Effective Theory (SCET). Our formalism applies to both SCET-1 and SCET-2 soft functions and we clarify the relation between the respective soft anomalous dimension and the collinear anomaly exponent. We confirm existing two-loop results for about a dozen dijet soft functions and obtain new predictions for the angularity event shape and the soft-drop jet-grooming algorithm.

The energy liberated by fallback accretion has been suggested as a possible engine to power hydrogen-poor superluminous supernovae (SLSNe). We systematically investigate this model using the Bayesian light curve (LC) fitting code MOSFiT (Modular Open Source Fitter for Transients), fitting the LCs of 37 hydrogen-poor SLSNe assuming a fallback accretion central engine. We find that this model can yield good fits to their LCs, with a fit quality that rivals the popular magnetar engine models. Examining our derived parameters for the fallback model, we estimate the total energy requirements from the accretion disk to be 0.002-0.7 {\text{}}{M}_⊙ c ². If we adopt a typical conversion efficiency ∼10^-3, the required mass to accrete is thus 2-700 {\text{}}{M}_⊙ . Many SLSNe, therefore, require an unrealistic accretion mass, and so only a fraction of these events could be powered by fallback accretion unless the true efficiency is much greater than our fiducial value. The SLSNe that require the smallest amounts of fallback mass are still fallback accretion-powered supernova candidates, but they are difficult to distinguish solely by their LC properties.

We derive from ambitwistor strings new formulae for two-loop scattering amplitudes in supergravity and super-Yang-Mills theory, with any number of particles. We start by constructing a formula for the type II ambitwistor string amplitudes on a genus-two Riemann surface, and then study the localisation of the moduli space integration on a degenerate limit, where the genus-two surface turns into a Riemann sphere with two nodes. This leads to scattering amplitudes in supergravity, expressed in the formalism of the two-loop scattering equations. For super-Yang-Mills theory, we import `half' of the supergravity result, and determine the colour dependence by considering a current algebra on the nodal Riemann sphere, thereby completely specifying the two-loop analogue of the Parke-Taylor factor, including non-planar contributions. We also present in appendices explicit expressions for the Szegő kernels and the partition functions for even spin structures, up to the relevant orders in the degeneration parameters, which may be useful for related investigations in conventional superstring theory.

Imaging of the dust continuum emitted from disks around nearby protostars reveals diverse substructure. In recent years, theoretical efforts have been intensified to investigate how far the intrinsic dynamics of protoplanetary disks (PPDs) can lead to such features. Turbulence in the realm of non-ideal magnetohydrodynamics (MHD) is one candidate for explaining the generation of zonal flows which can lead to local dust enhancements. Adopting a radially varying cylindrical disk model, and considering combinations of vertical and azimuthal initial net flux, we perform 3D non-ideal MHD simulations aimed at studying self-organization induced by the Hall effect in turbulent PPDs. To this end, new modules have been incorporated into the NIRVANA-III and FARGO3D MHD codes. We moreover include dust grains, treated in the fluid approximation, in order to study their evolution subject to the emerging zonal flows. In the regime of a dominant Hall effect, we robustly obtain large-scale organized concentrations in the vertical magnetic field that remain stable for hundreds of orbits. For disks with vertical initial net flux alone, we confirm the presence of zonal flows and vortices that introduce regions of super-Keplerian gas flow. Including a moderately strong net-azimuthal magnetic flux can significantly alter the dynamics, partially preventing the self-organization of zonal flows. For plasma beta-parameters smaller than 50, large-scale, near-axisymmetric structures develop in the vertical magnetic flux. In all cases, we demonstrate that the emerging features are capable of accumulating dust grains for a range of Stokes numbers.

We consider implications of high-energy neutrino emission from blazar flares, including the recent event IceCube-170922A and the 2014-2015 neutrino flare that could originate from TXS 0506+056. First, we discuss their contribution to the diffuse neutrino intensity taking into account various observational constraints. Blazars are likely to be subdominant in the diffuse neutrino intensity at sub-PeV energies, and we show that blazar flares like those of TXS 0506+056 could make ≲1%-10% of the total neutrino intensity. We also argue that the neutrino output of blazars can be dominated by the flares in the standard leptonic scenario for their γ-ray emission, and energetic flares may still be detected with a rate of ≲ 1 {yr}}^-1. Second, we consider multi-messenger constraints on the source modeling. We show that luminous neutrino flares should be accompanied by luminous broadband cascade emission, emerging also in X-rays and γ-rays. This implies that not only γ-ray telescopes like Fermi but also X-ray sky monitors such as Swift and MAXI are critical to test the canonical picture based on the single-zone modeling. We also suggest a two-zone model that can naturally satisfy the X-ray constraints while explaining the flaring neutrinos via either photomeson or hadronuclear processes.

Several protoplanetary discs observed by ALMA show dust concentrations consistent with particle trapping in giant vortices. The formation and survival of vortices are of major importance for planet formation because vortices act as particle traps and are therefore preferred locations of planetesimal formation. Recent studies showed that the vertical shear instability (VSI) is capable of generating turbulence and small vortices in protoplanetary discs that have the proper radial and vertical stratification and thermally relax on sufficiently short time-scales. But the effect of the azimuthal extend of the disc is often neglected as the discs azimuth is limited to Δϕ ≤ π/2. We aim to investigate the influence of the azimuthal extent of the disc on the long-term evolution of a protoplanetary disc and the possibility of large vortices forming. To this end, we perform 3D simulations for up to 1000 local orbits using different values of Δϕ = π/2 to 2π for VSI in discs with a prescribed radial density and temperature gradient cooling on short time-scales. We find the VSI capable of forming large vortices that can exist at least several hundred orbits in simulations covering a disc with Δϕ ≥ π. This suggests the VSI to be capable to form vortices or at least to trigger vortex formation via a secondary instability, e.g. Rossby wave instability or Kelvin-Helmholtz Instability.

Superluminous supernovae (SLSNe) are at least ∼5 times more luminous than common supernovae. Especially hydrogen-poor SLSN-I are difficult to explain with conventional powering mechanisms. One possible scenario that might explain such luminosities is that SLSNe-I are powered by an internal engine, such as a magnetar or an accreting black hole. Strong magnetic fields or collimated jets can circularly polarize light. In this work, we measured circular polarization of two SLSNe-I with the FOcal Reducer and low dispersion Spectrograph (FORS2) mounted at the ESO's Very Large Telescope. PS17bek, a fast-evolving SLSN-I, was observed around peak, while OGLE16dmu, a slowly evolving SLSN-I, was observed 100 d after maximum. Neither SLSN shows evidence of circularly polarized light; however, these non-detections do not rule out the magnetar scenario as the powering engine for SLSNe-I. We calculate the strength of the magnetic field and the expected circular polarization as a function of distance from the magnetar, which decreases very fast. Additionally, we observed no significant linear polarization for PS17bek at four epochs, suggesting that the photosphere near peak is close to spherical symmetry.

Multivariate analyses are emerging as important tools to understand properties of hadronic jets, which play a key role in the LHC experimental program. We take a first step towards precise and differential theory predictions, by calculating the cross section for e ⁺ e ^- → 2 jets differential in the angularities e _α and e _β . The logarithms of e _α and e _β in the cross section are jointly resummed to next-to-next-to-leading logarithmic accuracy, using the SCET₊ framework we developed, and are matched to the next-to-leading order cross section. We perform analytic one-loop calculations that serve as input for our numerical analysis, provide controlled theory uncertainties, and compare our results to P ythia. We also obtain predictions for the cross section differential in the ratio e _α /e _β , which cannot be determined from a fixed-order calculation. The effect of nonperturbative corrections is also investigated. Using E vent2, we validate the logarithmic structure of the single angularity cross section predicted by factorization theorems at O({α}_s^2) , highlighting the importance of recoil for specific angularities when using the thrust axis as compared to the winner-take-all axis.

Previous work has shown that massless tree amplitudes of the type I and IIA/B superstrings can be dramatically simplified by expressing them as double copies between field-theory amplitudes and scalar disk/sphere integrals, the latter containing all the α^'-corrections. In this work, we pinpoint similar double-copy constructions for the heterotic and bosonic string theories using an α ^' -dependent field theory and the same disk/sphere integrals. Surprisingly, this field theory, built out of dimension-six operators such as ( D _μ F ^μν )², has previously appeared in the double-copy construction of conformal supergravity. We elaborate on the α ^' → ∞ limit in this picture and derive new amplitude relations for various gauge-gravity theories from those of the heterotic string.

We formulate some first fundamental elements of an approach for assessing the logarithmic accuracy of parton-shower algorithms based on two broad criteria: their ability to reproduce the singularity structure of multi-parton matrix elements, and their ability to reproduce logarithmic resummation results. We illustrate our approach by considering properties of two transverse-momentum ordered final-state showers, examining features up to second order in the strong coupling. In particular we identify regions where they fail to reproduce the known singular limits of matrix elements. The characteristics of the shower that are responsible for this also affect the logarithmic resummation accuracies of the shower, both in terms of leading (double) logarithms at subleading N_C and next-to-leading (single) logarithms at leading N_C.

Using the M31 PAndromeda Cepheid sample and the HST PHAT data, we obtain the largest Cepheid sample in M31 with HST data in four bands. For our analysis we consider three samples: a very homogeneous sample of Cepheids based on the PAndromeda data, the mean magnitude corrected PAndromeda sample and a sample complementing the PAndromeda sample with Cepheids from the literature. The latter results in the largest catalog with 522 fundamental mode (FM) Cepheids and 102 first overtone (FO) Cepheids with F160W and F110W data and 559 FM Cepheids and 111 FO Cepheids with F814W and F475W data. The obtained dispersion of the period-luminosity relations (PLRs) is very small (e.g., 0.138 mag in the F160W sample I PLR). We find no broken slope in the PLRs when analyzing our entire sample, but we do identify a subsample of Cepheids that causes the broken slope. However, this effect only shows when the number of this Cepheid type makes up a significant fraction of the total sample. We also analyze the sample selection effect on the Hubble constant.

In this paper we study the fragmentation of a parton into a jet containing a heavy quark. When heavy quarks are involved in a jet, the quark mass can lead to a numerically significant correction to the jet cross section and its substructure. With this motivation, we calculated the heavy quark mass effects to next-to-leading order in α_s on the fragmentation functions to a jet (FFJs) and the jet fragmentation functions (JFFs), where the former describes fragmentation of parton into a jet and the latter describes fragmenting processes inside a jet. The finite size of the heavy quark mass does not change the ultraviolet behaviors, but it can give significant corrections to the finite contributions. When we take the zero mass limit, we find that the FFJs and the JFFs reproduce established results for massless partons. If we define the heavy quark jet as one that include at least one heavy (anti-)quark, the tagged heavy quark jet production is sensitive to the heavy quark mass and produces large logarithms of the mass. Taking advantage of the FFJs and JFFs, we formulate a factorization theorem for heavy quark jet production in order to resum these large logarithms systematically. As an application, we study inclusive b-jet production and show phenomenological implications due to keeping a non-zero quark mass.

All four-point mixed gluon-graviton amplitudes in pure Einstein-Yang-Mills theory with at most one state of negative helicity are computed at one-loop order and maximal powers of the gauge coupling, using D-dimensional generalized unitarity. The resulting purely rational expressions take very compact forms. We comment on the color-kinematics duality and a relation to collinear limits of pure gluon amplitudes.

The nature of type II Cepheids and anomalous Cepheids is still not well known and their evolutionary channels leave many unanswered questions. We use complete collection of classical pulsating stars in the Magellanic Clouds discovered by the OGLE project, to compare their spatial distributions, which are one of the characteristic features directly related to the star formation history. In this analysis we use 9649 classical Cepheids, 262 anomalous Cepheids, 338 type II Cepheids and 46 443 RR Lyr stars from both Magellanic Clouds. We compute three-dimensional Kolmogorov-Smirnov tests for every possible pair of type II and anomalous Cepheids with classical Cepheids, and RR Lyr stars. We confirm that BL Her stars are as old as RR Lyr variable stars - their spatial distributions are similar, and they create a vast halo around both galaxies. We discover that spatial distribution of W Vir stars has attributes characteristic for both young and old stellar populations. Hence, it seems that these similarities are related to the concentration of these stars in the center of the Large Magellanic Cloud, and the lack of a vast halo. This leads to the conclusion that W Vir variables could be a mixture of old and intermediate-age stars. Our analysis of the three-dimensional distributions of anomalous Cepheids shows that they differ significantly from classical Cepheids. Statistical tests of anomalous Cepheids distributions with RR Lyr distributions do not give unambiguous results. We consider that these two distributions can be similar through the vast halos they create. This similarity would confirm anomalous Cepheids evolution scenario that assumes coalescence of a binary system.

The consequences of phase transitions in the early universe are becoming testable in a variety of manners, from colliders physics to gravitational wave astronomy. In particular one phase transition we know of, the electroweak phase transition (EWPT), could potentially be first order in BSM scenarios and testable in the near future. If confirmed this could provide a mechanism for baryogenesis, which is one of the most important outstanding questions in physics. To reliably make predictions it is necessary to have full control of the finite temperature scalar potentials. However, as we show the standard methods used in BSM physics to improve phase transition calculations, resumming hard thermal loops, introduces significant errors into the scalar potential. In addition, the standard methods make it impossible to match theories to an EFT description reliably. In this paper we define a thermal resummation procedure based on partial dressing (PD) for general BSM calculations of phase transitions beyond the high-temperature approximation. Additionally, we introduce the modified optimized partial dressing (OPD) procedure, which is numerically nearly as efficient as old incorrect methods, while yielding identical results to the full PD calculation. This can be easily applied to future BSM studies of phase transitions in the early universe. As an example, we show that in unmixed singlet scalar extensions of the SM, the (O)PD calculations make new phenomenological predictions compared to previous analyses. An important future application is the study of EFTs at finite temperature.

We present a next-to-leading order accurate simulation of t-channel single-top plus jet production matched to parton showers via the Powheg method. The calculation underlying the simulation is enhanced with a process-specific implementation of the multi-scale improved NLO (Minlo) method, such that it gives physical predictions all through phase space, including regions where the jet additional to the t-channel single-top process is unresolved. We further describe a tuning procedure for the Minlo Sudakov form factor, fitting the coefficient of the first subleading term in its exponent using an artificial neural-network. The latter tuning, implemented as a straightforward event-by-event reweighting, renders the Minlo simulation NLO accurate for t-channel single-top observables, in addition to those of the analogous single-top plus jet process.

We report the discovery of Serenity-18, a galaxy at z ≃ 5.939 for which we could measure the content of molecular gas, M(H₂) ≃ 5 × 10⁹ M _⊙, traced by the CO(6-5) emission, together with the metal-poor ([Fe/H] =-3.08 ± 0.12, [Si/H] = -2.86 ± 0.14) gas clump/filament which is possibly feeding its growth. The galaxy has an estimated star formation rate of ≈100 M _⊙ yr^-1, implying that it is a typical main sequence galaxy at these redshifts. The metal-poor gas is detected through a damped Lyα absorber (DLA) observed at a spatial separation of 40 kpc and at the same redshift of Serenity-18, along the line of sight to the quasar SDSS J2310+1855 (z _em ≃ 6.0025). The chemical abundances measured for the damped Lyα system are in very good agreement with those measured for other DLAs discovered at similar redshifts, indicating an enrichment due to massive PopII stars. The galaxy/damped system that we discovered is a direct observational evidence of the assembly of a galaxy at the edge of the reionization epoch.

Based on ALMA and ESO VLT observations.

The growth process of protoplanets can be sped up by accreting a large number of solid, pebble-sized objects that are still present in the protoplanetary disc. It is still an open question on how efficient this process works in realistic turbulent discs. We investigate the accretion of pebbles in turbulent discs that are driven by the purely hydrodynamical vertical shear instability (VSI). For this purpose, we performed global 3D simulations of locally isothermal, VSI turbulent discs that have embedded protoplanetary cores from 5 to 100 M_⊕, which are placed at 5.2 au distance from the star. In addition, we followed the evolution of a swarm of embedded pebbles of different sizes under the action of drag forces between gas and particles in this turbulent flow. Simultaneously, we performed a set of comparison simulations for laminar viscous discs where the particles experience stochastic kicks. For both cases, we measured the accretion rate onto the cores as a function of core mass and Stokes number (τ_s) of the particles and compared these values to recent magneto-rotational instability (MRI) turbulence simulations. Overall the dynamic is very similar for the particles in the VSI turbulent disc and the laminar case with stochastic kicks. For small mass planets (i.e. 5-10 M_⊕), well-coupled particles with τ_s = 1, which have a size of about 1 m at this location, we find an accretion efficiency (rate of particles accreted over drifting inwards) of about 1.6-3%. For smaller and larger particles, this efficiency is higher. However, the fast inwards drift for τ_s = 1 particles makes them the most effective for rapid growth, leading to mass doubling times of about 20 000 yr. For masses between 10 and 30 M_⊕ the core reaches the pebble isolation mass and the particles are trapped at the pressure maximum just outside of the planet, shutting off further particle accretion.

The V-A structure of the weak interactions leads to definite amplitude hierarchies in exclusive heavy-to-light decays mediated by b → ( d, s) γ and b\to (d, s)ℓ \overline{ℓ} . However, the extraction of right-handed currents beyond the Standard Model is contaminated by V-A long-distance contributions leaking into right-handed amplitudes. We propose that these quantum-number changing long-distance contributions can be controlled by considering the almost parity-degenerate vector meson final states by exploiting the opposite relative sign of left- versus right-handed amplitudes. For example, measuring the time-dependent rates of a pair of vector V ( J ^P = 1^-) and axial A(1⁺) mesons in B → ( V, A) γ, up to an order of magnitude is gained on the theory uncertainty prediction, controlled by long-distance ratios to the right-handed amplitude. This renders these decays clean probes to null tests, from the theory side.

We have surveyed Kepler’s supernova remnant in search of the companion star of the explosion. We have gone as deep as 2.6 L _⊙ in all stars within 20% of the radius of the remnant. We use FLAMES at the VLT-UT2 telescope to obtain high-resolution spectra of the stellar candidates selected from Hubble Space Telescope (HST) images. The resulting set of stellar parameters suggests that these stars come from a rather ordinary mixture of field stars (mostly giants). A few of the stars seem to have low [Fe/H] (<-1) and they are consistent with being metal-poor giants. The radial velocities and rotational velocities v _rot sin i are very well determined. There are no fast rotating stars because v _rot sin i < 20 km s^-1 for all the candidates. The radial velocities from the spectra and the proper motions determined from HST images are compatible with those expected from the Besançon model of the Galaxy. The strong limits placed on luminosity suggest that this supernova could have arisen either from the core-degenerate scenario or from the double-degenerate scenario.

We develop the framework to perform all-orders resummation of electroweak logarithms of Q/M for inclusive scattering processes at energies Q much above the electroweak scale M. We calculate all ingredients needed at next-to-leading logarithmic (NLL) order and provide an explicit recipe to implement this for 2 → 2 processes. PDF evolution including electroweak corrections, which lead to Sudakov double logarithms, is computed. If only the invariant mass of the final state is measured, all electroweak logarithms can be resummed by the PDF evolution, at least to LL. However, simply identifying a lepton in the final state requires the corresponding fragmentation function and introduces angular dependence through the exchange of soft gauge bosons. Furthermore, we show the importance of polarization effects for gauge bosons, due to the chiral nature of SU(2) — even the gluon distribution in an unpolarized proton becomes polarized at high scales due to electroweak effects. We justify our approach with a factorization analysis, finding that the objects entering the factorization theorem do not need to be SU(2) × U(1) gauge singlets, even though we perform the factorization and resummation in the symmetric phase. We also discuss a range of extensions, including jets and how to calculate the EW logarithms when you are fully exclusive in the central (detector) region and fully inclusive in the forward (beam) regions.

Starting from a factorization theorem in effective field theory, we derive a parton-shower equation for the resummation of non-global logarithms. We have implemented this shower and interfaced it with a tree-level event generator to obtain an automated framework to resum the leading logarithm of non-global observables in the large- N _c limit. Using this setup, we compute gap fractions for dijet processes and isolation cone cross sections relevant for photon production. We compare our results with fixed-order computations and LHC measurements. We find that naive exponentiation is often not adequate, especially when the vetoed region is small, since non-global contributions are enhanced due to their dependence on the veto-region size. Since our parton shower is derived from first principles and based on renormalization-group evolution, it is clear what ingredients will have to be included to perform resummations at subleading logarithmic accuracy in the future.

We evaluate analytically the master integrals for double real radiation emission in the <inline-formula id="IEq1"><mml:math><mml:mrow><mml:mi>b</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>u</mml:mi><mml:msup><mml:mi>W</mml:mi><mml:mo>∗</mml:mo></mml:msup></mml:mrow></mml:math></inline-formula> decay, where b and u are a massive and massless quark, respectively, while <inline-formula id="IEq2"><mml:math><mml:msup><mml:mi>W</mml:mi><mml:mrow><mml:mrow></mml:mrow><mml:mo>∗</mml:mo></mml:mrow></mml:msup></mml:math></inline-formula> is an off-shell charged weak boson. Since the W boson can subsequently decay in a lepton anti-neutrino pair, the results of the present paper constitute a further step toward a fully analytic computation of differential distributions for the semileptonic decay of a b quark at NNLO in QCD. The latter partonic process plays a crucial role in the study of inclusive semileptonic charmless decays of B mesons. Our results are expressed in terms of multiple polylogarithms of maximum weight four.

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.

We present the computational framework MATRIX (http://matrix.hepforge.org/) which allows us to evaluate fully differential cross sections for a wide class of processes at hadron colliders in next-to-next-to-leading order (NNLO) QCD. The processes we consider are <inline-formula id="IEq1"><mml:math><mml:mrow><mml:mn>2</mml:mn><mml:mo stretchy="false">→</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math></inline-formula> and <inline-formula id="IEq2"><mml:math><mml:mrow><mml:mn>2</mml:mn><mml:mo stretchy="false">→</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:math></inline-formula> hadronic reactions involving Higgs and vector bosons in the final state. All possible leptonic decay channels of the vector bosons are included for the first time in the calculations, by consistently accounting for all resonant and non-resonant diagrams, off-shell effects and spin correlations. We briefly introduce the theoretical framework MATRIX is based on, discuss its relevant features and provide a detailed description of how to use MATRIX to obtain NNLO accurate results for the various processes. We report reference predictions for inclusive and fiducial cross sections of all the physics processes considered here and discuss their corresponding uncertainties. MATRIX features an automatic extrapolation procedure that allows us, for the first time, to control the systematic uncertainties inherent to the applied NNLO subtraction procedure down to the few permille level (or better).

We compute dual-conformally invariant ladder integrals that are capped off by pentagons at each end of the ladder. Such integrals appear in six-point amplitudes in planar N = 4 super-Yang-Mills theory. We provide exact, finite-coupling formulas for the basic double pentaladder integrals as a single Mellin integral over hypergeometric functions. For particular choices of the dual conformal cross ratios, we can evaluate the integral at weak coupling to high loop orders in terms of multiple polylogarithms. We argue that the integrals are exponentially suppressed at strong coupling. We describe the space of functions that contains all such double pentaladder integrals and their derivatives, or coproducts. This space, a prototype for the space of Steinmann hexagon functions, has a simple algebraic structure, which we elucidate by considering a particular discontinuity of the functions that localizes the Mellin integral and collapses the relevant symbol alphabet. This function space is endowed with a coaction, both perturbatively and at finite coupling, which mixes the independent solutions of the hypergeometric differential equation and constructively realizes a coaction principle of the type believed to hold in the full Steinmann hexagon function space.

We present combined observations of the {NH}}₃ (J, K) = (1, 1) and (2, 2) inversion transitions toward OMC1 in Orion A obtained by the Karl G. Jansky Very Large Array and the 100 m Robert C. Byrd Green Bank Telescope. With an angular resolution of 6″ (0.01 pc), these observations reveal with unprecedented detail the complex filamentary structure extending north of the active Orion BN/KL region in a field covering ∼6‧ × 7‧. We find a 0.012 pc wide filament within OMC1, with an aspect ratio of ∼37:1, that was missed in previous studies. Its orientation is directly compared to the relative orientation of the magnetic field from the James Clerk Maxwell Telescope BISTRO survey in Orion A. We find a small deviation of ∼11° between the mean orientation of the filament and the magnetic field, suggesting that they are almost parallel to one another. The filament’s column density is estimated to be 2-3 orders of magnitude larger than the filaments studied with Herschel and is possibly self-gravitating, given the low values of turbulence found. We further produce maps of the gas kinematics by forward modeling the hyperfine structure of the {NH}}₃ (J, K) = (1, 1) and (2, 2) lines. The resulting distribution of velocity dispersions peaks at ∼0.5 km s^-1, close to the subsonic regime of the gas. This value is about 0.2 km s^-1 smaller than previously measured in single-dish observations of the same region, suggesting that higher angular and spectral resolution observations will identify even lower velocity dispersions that might reach the subsonic turbulence regime in dense gas filaments.

We present Hubble Space Telescope (HST) photometry of a selected sample of 50 long-period, low-extinction Milky Way Cepheids measured on the same WFC3 F555W-, F814W-, and F160W-band photometric system as extragalactic Cepheids in Type Ia supernova host galaxies. These bright Cepheids were observed with the WFC3 spatial scanning mode in the optical and near-infrared to mitigate saturation and reduce pixel-to-pixel calibration errors to reach a mean photometric error of 5 mmag per observation. We use the new Gaia DR2 parallaxes and HST photometry to simultaneously constrain the cosmic distance scale and to measure the DR2 parallax zeropoint offset appropriate for Cepheids. We find the latter to be -46 ± 13 μas or ±6 μas for a fixed distance scale, higher than found from quasars, as expected for these brighter and redder sources. The precision of the distance scale from DR2 has been reduced by a factor of 2.5 because of the need to independently determine the parallax offset. The best-fit distance scale is 1.006 ± 0.033, relative to the scale from Riess et al. with H ₀ = 73.24 km s^-1 Mpc^-1 used to predict the parallaxes photometrically, and is inconsistent with the scale needed to match the Planck 2016 cosmic microwave background data combined with ΛCDM at the 2.9σ confidence level (99.6%). At 96.5% confidence we find that the formal DR2 errors may be underestimated as indicated. We identify additional errors associated with the use of augmented Cepheid samples utilizing ground-based photometry and discuss their likely origins. Including the DR2 parallaxes with all prior distance-ladder data raises the current tension between the late and early universe route to the Hubble constant to 3.8σ (99.99%). With the final expected precision from Gaia, the sample of 50 Cepheids with HST photometry will limit to 0.5% the contribution of the first rung of the distance ladder to the uncertainty in H ₀.

The collapse of dust particle clouds directly to kilometer-sized planetesimals is a promising way to explain the formation of planetesimals, asteroids, and comets. In the past, this collapse has been studied in stratified shearing box simulations with super-solar dust-to-gas ratio ɛ, allowing for streaming instability (SI) and gravitational collapse. This paper studies the non-stratified SI under dust-to-gas ratios from ɛ =0.1 up to ɛ =1000 without self-gravity. The study covers domain sizes of L=0.1 {{H}}, 0.01 {{H}}, and 0.001 {{H}} in terms of the gas-disk scale height {{H}} using the PENCILCODE. They are performed in radial-azimuthal (2D) and radial-vertical (2.5D) extents. The used particles of {St}=0.01 and 0.1 mark the upper end of the expected dust growth. SI activity is found up to very high dust-to-gas ratios, providing fluctuations in the local dust-to-gas ratios and turbulent particle diffusion δ. We find an SI-like instability that operates in r-φ, even when vertical modes are suppressed. This new azimuthal streaming instability (aSI) shows similar properties and appearance as the SI. Both, SI and aSI show diffusivity at ɛ =100 only to be two orders of magnitude lower than at ɛ =1, suggesting a δ ∼ {ɛ }^-1. relation that is shallow around ɛ ≈ 1. The (a)SI ability to concentrate particles is found to be uncorrelated with its strength in particle turbulence. Finally, we performed a resolution study to test our findings of the aSI. This paper stresses the importance of properly resolving the (a)SI at high dust-to-gas ratios and planetesimal collapse simulations, leading otherwise to potentially incomplete results.

The theoretical interpretation of dark matter direct detection experiments is hindered by uncertainties of the microphysics governing the dark matter-nucleon interaction, and of the dark matter density and velocity distribution inside the Solar System. These uncertainties are especially relevant when confronting a detection claim to the null results from other experiments, since seemingly conflicting experimental results may be reconciled when relaxing the assumptions about the form of the interaction and/or the velocity distribution. We present in this paper a halo-independent method to calculate the maximum number of events in a direct detection experiment given a set of null search results, allowing for the first time the scattering to be mediated by an arbitrary combination of various interactions (concretely we consider up to 64). We illustrate this method to examine the compatibility of the dark matter interpretation of the three events detected by the silicon detectors in the CDMS-II experiment with the null results from XENON1T and PICO-60.

We consider idealized parton shower event generators that treat parton spin and color exactly, leaving aside the choice of practical approximations for spin and color. We investigate how the structure of such a parton shower generator is related to the structure of QCD. We argue that a parton shower with splitting functions proportional to α_s can be viewed not just as a model, but as the lowest order approximation to a shower that is defined at any perturbative order. To support this argument, we present a formulation for a parton shower at order α_s^k for any k . Since some of the input functions needed are specified by their properties but not calculated, this formulation does not provide a useful recipe for an order α_s^k parton shower algorithm. However, in this formulation we see how the operators that generate the shower are related to operators that specify the infrared singularities of QCD.

We explore jet physics in hadron collisions using the parton shower event generator Deductor. Of particular interest is the one jet inclusive cross section d σ /d P_T for jets of very high P_T. Compared to the Born level, the cross section decreases substantially because of P_T loss from the jet during showering. We compare to the same effect in Pythia and Dire. The cross section then increases substantially because of the summation of threshold logarithms included in Deductor. We also study the cross section to have a gap with no jets between two hard jets that are widely separated in rapidity. Here we compare Atlas data to Deductor with virtuality based ordering and to Deductor with k_T ordering. We also compare with perturbation theory. In both cases, we check whether adding an underlying event and hadronization has a significant effect beyond that found with just a parton shower.

Systems of integration-by-parts identities play an important role in simplifying the higher-loop Feynman integrals that arise in quantum field theory. Solving these systems is equivalent to reducing integrals containing numerator products of irreducible invariants to a small set of master integrals. We present a new approach to solving these systems that finds direct reduction equations for numerator terms of a given Feynman integral. As a particular example of its power, we show how to obtain reduction equations for arbitrary powers of irreducible invariants, along with their solutions.

The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully calibrated with Ly α forest data. We compare these with cosmological simulations run using a spatially homogeneous ionizing background. The simulations with a realistic growth of ionized regions and a realistic spread in reionization redshifts show, as expected, significant spatial fluctuations in the temperature-density relation (TDR) of the post-reionization IGM. The most recently ionized regions are hottest and exhibit a flatter TDR. In simulations consistent with the average TDR inferred from Ly α forest data, these spatial fluctuations have a moderate but noticeable effect on the statistical properties of the Ly α opacity of the IGM at z ∼ 4-6. This should be taken into account in accurate measurements of the thermal properties of the IGM and the free-streaming of dark matter from Ly α forest data in this redshift range. The spatial variations of the TDR predicted by our simulations are, however, smaller by about a factor of 2 than would be necessary to explain the observed large spatial opacity fluctuations on large (≥50 h^-1 comoving Mpc) scales atz ≳ 5.5.

We present the key features relevant to the automated computation of all the leading- and next-to-leading order contributions to short-distance cross sections in a mixed-coupling expansion, with special emphasis on the first subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW corrections. We discuss, in particular, the FKS subtraction in the context of a mixed-coupling expansion; the extension of the FKS subtraction to processes that include final-state tagged particles, defined by means of fragmentation functions; and some properties of the complex mass scheme. We combine the present paper with the release of a new version of MADGRAPH5_AMC@NLO, capable of dealing with mixed-coupling expansions. We use the code to obtain illustrative inclusive and differential results for the 13-TeV LHC.

Gas giants' early (≲5 Myr) orbital evolution occurs in a disc losing mass in part to photoevaporation driven by high energy irradiance from the host star. This process may ultimately overcome viscous accretion to disperse the disc and halt migrating giants by starving their orbits of gas, imprinting on giant planet separations in evolved systems. Inversion of this distribution could then give insight into whether the stellar FUV, EUV or X-ray flux dominates photoevaporation, constraining planet formation and disc evolution models. We use a 1D hydrodynamic code in population syntheses for gas giants undergoing Type II migration in a viscously evolving disc subject to either a primarily FUV, EUV or X-ray flux from a pre-solar T Tauri star. The photoevaporative mass loss profile's unique peak location and width in each energetic regime produces characteristic features in the distribution of giant separations: a severe dearth of ≲2 M_J planets interior to 5 au in the FUV scenario, a sharp concentration of ≲3 M_J planets between ≈1.5-2 au in the EUV case and a relative abundance of ≈2-3.5 M_J giants interior to 0.5 au in the X-ray model. These features do not resemble the observational sample of gas giants with mass constraints, although our results do show some weaker qualitative similarities. We thus assess how the differing photoevaporative profiles interact with migrating giants and address the effects of large model uncertainties as a step to better connect disc models with trends in the exoplanet population.

The absence of confirmed signal in dark matter (DM) direct detection (DD) may suggest weak interaction strengths between DM and the abundant constituents inside nucleon, i.e. gluons and valence light quarks. In this work we consider a real scalar dark matter S interacting only with SU(2)_L singlet Up-type quarks U_i = u_R,c_R,t_R via a vector-like fermion ψ which has the same quantum number as U_i. The DM-nucleon scattering can proceed through both h-mediated Higgs portal (HP) and ψ-mediated vector-like portal (VLP), in which HP can receive sizable radiative corrections through the new fermions. We first study the separate constraints on the new Yukawa couplings y_i and find that the constraints of XENON1T results are strong on y₁ from VLP scattering and on y₃ from its radiative contributions to HP scattering. Since both DM-light quark interactions and HP have been well studied in the existing literature, we move forward to focus on DM-heavy quark interactions. Since there is no valence c,t quark inside nucleons at μ_had ~ 1 GeV, y₂,y₃ interactions are manifested in DM-gluon scattering at loop level. We find that renormalization group equation (RGE) and heavy quark threshold effects are important if one calculates the DM-nucleon scattering rate σ^SI_p at μ_had ~ 1 GeV while constructing the effective theory at μ_EFT ~ m_Z. For the benchmarks y₃ = 0.5, y₂ = 0.5, 1, 3, combined results from Ω_DM h² simeq 0.12, XENON1T, Fermi-LAT, 13 TeV LHC data have almost excluded m_S < m_t/2 when only DM-{c,t} interactions are considered. FCNC of top quark can be generated at both tree level t → ψ^(*)S → cSS and loop level t → c+γ/g/Z, of which the branching fractions are typically below 10^-9 after passing the other constraints, which are still safe from the current top quark width measurements.

In this Letter, we provide evidence for a new double-copy structure in one-loop amplitudes of the open superstring. Their integrands with respect to the moduli space of genus-one surfaces are cast into a form where gauge-invariant kinematic factors and certain functions of the punctures—so-called generalized elliptic integrands—enter on completely symmetric footing. In particular, replacing the generalized elliptic integrands by a second copy of kinematic factors maps one-loop open-string correlators to gravitational matrix elements of the higher-curvature operator R⁴ .

We investigate the light-curve properties of a sample of 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in the Palomar Transient Factory survey. These events are brighter than SNe Ib/c and SNe Ic-BL, on average, by about 4 and 2 mag, respectively. The peak absolute magnitudes of SLSNe-I in rest-frame g band span -22 ≲ M _g ≲ -20 mag, and these peaks are not powered by radioactive ⁵⁶Ni, unless strong asymmetries are at play. The rise timescales are longer for SLSNe than for normal SNe Ib/c, by roughly 10 days, for events with similar decay times. Thus, SLSNe-I can be considered as a separate population based on photometric properties. After peak, SLSNe-I decay with a wide range of slopes, with no obvious gap between rapidly declining and slowly declining events. The latter events show more irregularities (bumps) in the light curves at all times. At late times, the SLSN-I light curves slow down and cluster around the ⁵⁶Co radioactive decay rate. Powering the late-time light curves with radioactive decay would require between 1 and 10 M _⊙ of Ni masses. Alternatively, a simple magnetar model can reasonably fit the majority of SLSNe-I light curves, with four exceptions, and can mimic the radioactive decay of ⁵⁶Co, up to ∼400 days from explosion. The resulting spin values do not correlate with the host-galaxy metallicities. Finally, the analysis of our sample cannot strengthen the case for using SLSNe-I for cosmology.

We discuss a novel approach to systematically determine the dominant long-distance contribution to <inline-formula id="IEq3"><mml:math><mml:mrow><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mo>∗</mml:mo></mml:msup><mml:mi>ℓ</mml:mi><mml:mi>ℓ</mml:mi></mml:mrow></mml:math></inline-formula> decays in the kinematic region where the dilepton invariant mass is below the open charm threshold. This approach provides the most consistent and reliable determination to date and can be used to compute Standard Model predictions for all observables of interest, including the kinematic region where the dilepton invariant mass lies between the <inline-formula id="IEq4"><mml:math><mml:mrow><mml:mi>J</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>ψ</mml:mi></mml:mrow></mml:math></inline-formula> and the <inline-formula id="IEq5"><mml:math><mml:mrow><mml:mi>ψ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>2</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math></inline-formula> resonances. We illustrate the power of our results by performing a New Physics fit to the Wilson coefficient <inline-formula id="IEq6"><mml:math><mml:msub><mml:mi>C</mml:mi><mml:mn>9</mml:mn></mml:msub></mml:math></inline-formula>. This approach is systematically improvable from theoretical and experimental sides, and applies to other decay modes of the type <inline-formula id="IEq7"><mml:math><mml:mrow><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>V</mml:mi><mml:mi>ℓ</mml:mi><mml:mi>ℓ</mml:mi></mml:mrow></mml:math></inline-formula>, <inline-formula id="IEq8"><mml:math><mml:mrow><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>P</mml:mi><mml:mi>ℓ</mml:mi><mml:mi>ℓ</mml:mi></mml:mrow></mml:math></inline-formula> and <inline-formula id="IEq9"><mml:math><mml:mrow><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>V</mml:mi><mml:mi>γ</mml:mi></mml:mrow></mml:math></inline-formula>.

Direct searches for dark matter (DM) are continuously improving, probing down to lower and lower DM-nucleon interaction cross sections. For strongly interacting massive particle (SIMP) dark matter, however, the accessible cross section is bounded from above due to the stopping effect of the atmosphere, Earth, and detector shielding. We present a careful calculation of the SIMP signal rate, focusing on super-heavy DM (m_χ≳10⁵ GeV ) for which the standard nuclear-stopping formalism is applicable, and provide code for implementing this calculation numerically. With recent results from the low-threshold CRESST 2017 surface run, we improve the maximum cross section reach of direct detection searches by a factor of about 5000, for DM masses up to 1 0⁸ GeV . A reanalysis of the longer-exposure, subsurface CDMS-I results (published in 2002) improves the previous cross section reach by 2 orders of magnitude, for masses up to 1 0¹⁵ GeV . Along with complementary constraints from SIMP capture and annihilation in the Earth and Sun, these improved limits from direct nuclear scattering searches close a number of windows in the SIMP parameter space in the mass range 1 0⁶ GeV to 1 0¹³ GeV , of particular interest for heavy DM produced gravitationally at the end of inflation.

We present a calculation of the planar two-loop five-gluon amplitudes. The amplitudes are obtained in a variant of the generalized unitarity approach suitable for numerical computations, which we extend for use with finite field arithmetics. Employing a new method for the generation of unitarity-compatible integration-by-parts identities, all helicity amplitudes are reduced to a linear combination of master integrals for the first time. The approach allows us to compute exact values for the integral coefficients at rational phase-space points. All required master integrals are known analytically, and we obtain arbitrary-precision values for the amplitudes.

The form of higher-spin current interactions in the sector of one-forms is derived from the nonlinear higher-spin equations in AdS₄. Quadratic corrections to higher-spin equations are shown to be independent of the phase of the parameter η = exp ⁡ iφ in the full nonlinear higher-spin equations. The current deformation resulting from the nonlinear higher-spin equations is represented in the canonical form with the minimal number of space-time derivatives. The non-zero spin-dependent coupling constants of the resulting currents are determined in terms of the higher-spin coupling constant η η bar . Our results confirm the conjecture that (anti-)self-dual nonlinear higher-spin equations result from the full system at (η = 0) η bar = 0.

All measurements of cosmic star formation must assume an initial distribution of stellar masses—the stellar initial mass function—in order to extrapolate from the star-formation rate measured for typically rare, massive stars (of more than eight solar masses) to the total star-formation rate across the full stellar mass spectrum¹. The shape of the stellar initial mass function in various galaxy populations underpins our understanding of the formation and evolution of galaxies across cosmic time². Classical determinations of the stellar initial mass function in local galaxies are traditionally made at ultraviolet, optical and near-infrared wavelengths, which cannot be probed in dust-obscured galaxies^2,3, especially distant starbursts, whose apparent star-formation rates are hundreds to thousands of times higher than in the Milky Way, selected at submillimetre (rest-frame far-infrared) wavelengths^4,5. The ¹³C/¹⁸O isotope abundance ratio in the cold molecular gas—which can be probed via the rotational transitions of the ¹³CO and C¹⁸O isotopologues—is a very sensitive index of the stellar initial mass function, with its determination immune to the pernicious effects of dust. Here we report observations of ¹³CO and C¹⁸O emission for a sample of four dust-enshrouded starbursts at redshifts of approximately two to three, and find unambiguous evidence for a top-heavy stellar initial mass function in all of them. A low ¹³CO/C¹⁸O ratio for all our targets—alongside a well tested, detailed chemical evolution model benchmarked on the Milky Way⁶—implies that there are considerably more massive stars in starburst events than in ordinary star-forming spiral galaxies. This can bring these extraordinary starbursts closer to the `main sequence' of star-forming galaxies⁷, although such main-sequence galaxies may not be immune to changes in initial stellar mass function, depending on their star-formation densities.

We introduce a class of iterated integrals that generalize multiple polylogarithms to elliptic curves. These elliptic multiple polylogarithms are closely related to similar functions defined in pure mathematics and string theory. We then focus on the equal-mass and non-equal-mass sunrise integrals, and we develop a formalism that enables us to compute these Feynman integrals in terms of our iterated integrals on elliptic curves. The key idea is to use integration-by-parts identities to identify a set of integral kernels, whose precise form is determined by the branch points of the integral in question. These kernels allow us to express all iterated integrals on an elliptic curve in terms of them. The flexibility of our approach leads us to expect that it will be applicable to a large variety of integrals in high-energy physics.