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This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5 m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10–2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest. [ABSTRACT FROM AUTHOR]

In this paper we examine the factors that shape the distribution of molecular gas surface densities on the 150 pc scale across 67 morphologically diverse star-forming galaxies in the PHANGS-ALMA CO (2–1) survey. Dividing each galaxy into radial bins, we measure molecular gas surface density contrasts, defined here as the ratio between a fixed high percentile of the CO distribution and a fixed reference level in each bin. This reference level captures the level of the faint CO floor that extends between bright filamentary features, while the intensity level of the higher percentile probes the structures visually associated with bright, dense interstellar medium features like spiral arms, bars, and filaments. We compare these contrasts to matched percentile-based measurements of the 3.6 μm emission measured using Spitzer/IRAC imaging, which trace the underlying stellar mass density. We find that the logarithms of CO contrasts on 150 pc scales are 3–4 times larger than, and positively correlated with, the logarithms of 3.6 μm contrasts probing smooth nonaxisymmetric stellar bar and spiral structures. The correlation appears steeper than linear, consistent with the compression of gas as it flows supersonically in response to large-scale stellar structures, even in the presence of weak or flocculent spiral arms. Stellar dynamical features appear to play an important role in setting the cloud-scale gas density in our galaxies, with gas self-gravity perhaps playing a weaker role in setting the 150 pc scale distribution of gas densities. [ABSTRACT FROM AUTHOR]

In order to connect galaxy clusters to their progenitor protoclusters, we must constrain the star formation histories within their member galaxies and the timescale of virial collapse. In this paper we characterize the complex star-forming properties of a z = 2.5 protocluster in the COSMOS field using ALMA dust continuum and new Very Large Array CO (1–0) observations of two filaments associated with the structure, sometimes referred to as the "Hyperion" protocluster. We focus in particular on the protocluster "core," which has previously been suggested as the highest-redshift bona fide galaxy cluster traced by extended X-ray emission in a stacked Chandra/XMM image. We reanalyze these data and refute these claims, finding that at least 40% ± 17% of extended X-ray sources of similar luminosity and size at this redshift arise instead from inverse Compton scattering off recently extinguished radio galaxies rather than intracluster medium. Using ancillary COSMOS data, we also constrain the spectral energy distributions of the two filaments' eight constituent galaxies from the rest-frame UV to radio. We do not find evidence for enhanced star formation efficiency in the core and conclude that the constituent galaxies are already massive (M⋆ ≈ 1011M⊙), with molecular gas reservoirs >1010M⊙ that will be depleted within 200–400 Myr. Finally, we calculate the halo mass of the nested core at z = 2.5 and conclude that it will collapse into a cluster of (2–9) × 1014M⊙, comparable to the size of the Coma Cluster at z = 0 and accounting for at least 50% of the total estimated halo mass of the extended "Hyperion" structure. [ABSTRACT FROM AUTHOR]

Ultralight dark matter (ULDM) is currently one of the most popular classes of cosmological dark matter. The most important advantage is that ULDM with mass m ∼ 10−22 eV can account for the small-scale problems encountered in the standard cold dark matter model like the core–cusp problem, missing satellite problem, and the too-big-to-fail problem in galaxies. In this paper, we formulate a new simple model-independent analysis using the Spitzer Photometry and Accurate Rotation Curves data to constrain the range of ULDM mass. In particular, the most stringent constraint comes from the data of a galaxy ESO563–G021, which can conservatively exclude a ULDM mass range m = (0.14–3.11) × 10−22 eV. This model-independent excluded range is consistent with many bounds obtained by recent studies and it suggests that the ULDM proposal may not be able to alleviate the small-scale problems. [ABSTRACT FROM AUTHOR]

The colour bimodality of galaxies provides an empirical basis for theories of galaxy evolution. However, the balance of processes that begets this bimodality has not yet been constrained. A more detailed view of the galaxy population is needed, which we achieve in this paper by using unsupervised machine learning to combine multidimensional data at two different epochs. We aim to understand the cosmic evolution of galaxy subpopulations by uncovering substructures within the colour bimodality. We choose a clustering algorithm that models clusters using only the most discriminative data available, and apply it to two galaxy samples: one from the second edition of the GALEX-SDSS-WISE Legacy Catalogue (GSWLC-2; z ∼ 0.06), and the other from the VIMOS Public Extragalactic Redshift Survey (VIPERS; z ∼ 0.65). We cluster within a nine-dimensional feature space defined purely by rest-frame ultraviolet-through-near-infrared colours. Both samples are similarly partitioned into seven clusters, breaking down into four of mostly star-forming galaxies (including the vast majority of green valley galaxies) and three of mostly passive galaxies. The separation between these two families of clusters suggests differences in the evolution of their galaxies, and that these differences are strongly expressed in their colours alone. The samples are closely related, with star-forming/green-valley clusters at both epochs forming morphological sequences, capturing the gradual internally driven growth of galaxy bulges. At high stellar masses, this growth is linked with quenching. However, it is only in our low-redshift sample that additional, environmental processes appear to be involved in the evolution of low-mass passive galaxies. [ABSTRACT FROM AUTHOR]

Cosmic rays (CRs) are a plausible mechanism for launching winds of cool material from the discs of star-forming galaxies. However, there is no consensus on what types of galaxies likely host CR-driven winds, or what role these winds might play in regulating galaxies' star formation rates. Using a detailed treatment of the transport and losses of hadronic CRs developed in the previous paper in this series, here we develop a semi-analytical model that allows us to assess the viability of using CRs to launch cool winds from galactic discs. In particular, we determine the critical CR fluxes – and corresponding star formation rate surface densities – above which hydrostatic equilibrium within a given galaxy is precluded because CRs drive the gas off in a wind or otherwise render it unstable. Our model demonstrates that catastrophic, CR-driven wind loss is a possibility at galactic mean surface densities below |${\lesssim}10^2 \ \mathrm{ M}_{\odot }$| pc−2. In this regime – encompassing the Galaxy and local dwarfs – the locus of the CR-stability curve patrols the high side of the observed distribution of galaxies in the Kennicutt–Schmidt parameter space of star formation rate versus gas surface density. However, hadronic losses render CRs unable to drive global winds in galaxies with surface densities above the ∼102−103 M⊙ pc−2 transition region. Our results show that quiescent, low surface density galaxies like the Milky Way are poised on the cusp of instability, such that small changes to interstellar mass (ISM) parameters can lead to the launching of CR-driven outflows, and we suggest that, as a result, CR feedback sets an ultimate limit to the star formation efficiency of most modern galaxies. [ABSTRACT FROM AUTHOR]

Boxy, peanut-, or X-shaped 'bulges' are observed in a large fraction of barred galaxies viewed in, or close to, edge-on projection, as well as in the Milky Way. They are the product of dynamical instabilities occurring in stellar bars, which cause the latter to buckle and thicken vertically. Recent studies have found nearby galaxies that harbour two such features arising at different radial scales, in a nested configuration. In this paper, we explore the formation of such double peanuts, using a collisionless N -body simulation of a pure disc evolving in isolation within a live dark matter halo, which we analyse in a completely analogous way to observations of real galaxies. In the simulation, we find a stable double configuration consisting of two X/peanut structures associated with the same galactic bar – rotating with the same pattern speed – but with different morphology, formation time, and evolution. The inner, conventional peanut-shaped structure forms early via the buckling of the bar, and experiences little evolution once it stabilizes. This feature is consistent in terms of size, strength, and morphology, with peanut structures observed in nearby galaxies. The outer structure, however, displays a strong X, or 'bow-tie', morphology. It forms just after the inner peanut, and gradually extends in time (within 1–1.5 Gyr) to almost the end of the bar, a radial scale where ansae occur. We conclude that, although both structures form, and are dynamically coupled to, the same bar, they are supported by inherently different mechanisms. [ABSTRACT FROM AUTHOR]

The Solo (So litary Lo cal) Dwarf Galaxy survey is a volume-limited, wide-field g - and i -band survey of all known nearby (<3 Mpc) and isolated (>300 kpc from the Milky Way or M31) dwarf galaxies. This set of 44 dwarfs is homogeneously analysed for quantitative comparisons to the satellite dwarf populations of the Milky Way and M31. In this paper, an analysis of the 12 closest Solo dwarf galaxies accessible from the Northern hemisphere is presented, including derivation of their distances, spatial distributions, morphology, and extended structures, including their inner integrated light properties and their outer resolved star distributions. All 12 galaxies are found to be reasonably well described by two-dimensional Sérsic functions, although UGC 4879 in particular shows tentative evidence of two distinct components. No prominent extended stellar substructures, which could be signs of either faint satellites or recent mergers, are identified in the outer regions of any of the systems examined. [ABSTRACT FROM AUTHOR]

This paper presents a survey of Mg  ii absorbing gas in the vicinity of 380 random galaxies, using 156 background quasi-stellar objects (QSOs) as absorption-line probes. The sample comprises 211 isolated (73 quiescent and 138 star-forming galaxies) and 43 non-isolated galaxies with sensitive constraints for both Mg  ii absorption and H α emission. The projected distances span a range from d  = 9 to 497 kpc, redshifts of the galaxies range from z  = 0.10 to 0.48, and rest-frame absolute B -band magnitudes range from M B = −16.7 to −22.8. Our analysis shows that the rest-frame equivalent width of Mg  ii , Wr (2796), depends on halo radius (R h), B -band luminosity(L B), and stellar mass (M star) of the host galaxies, and declines steeply with increasing d for isolated, star-forming galaxies. At the same time, Wr (2796) exhibits no clear trend for either isolated, quiescent galaxies or non-isolated galaxies. In addition, the covering fraction of Mg  ii absorbing gas 〈κ〉 is high with 〈κ〉 ≳ 60 per cent at <40 kpc for isolated galaxies and declines rapidly to 〈κ〉 ≈ 0 at d ≳ 100 kpc. Within the gaseous radius, the incidence of Mg  ii gas depends sensitively on both M star and the specific star formation rate inferred from H α. Different from what is known for massive quiescent haloes, the observed velocity dispersion of Mg  ii absorbing gas around star-forming galaxies is consistent with expectations from virial motion, which constrains individual clump mass to |$m_{\rm cl} \gtrsim 10^5 \, \rm M_\odot$| and cool gas accretion rate of |$\sim 0.7\!-\!2 \, \mathrm{ M}_\odot \, \rm yr^{-1}$|⁠. Finally, we find no strong azimuthal dependence of Mg  ii absorption for either star-forming or quiescent galaxies. Our results demonstrate that multiple parameters affect the properties of gaseous haloes around galaxies and highlight the need of a homogeneous, absorption-blind sample for establishing a holistic description of chemically enriched gas in the circumgalactic space. [ABSTRACT FROM AUTHOR]

We present a new model for the evolution of gas phase metallicity gradients in galaxies from first principles. We show that metallicity gradients depend on four ratios that collectively describe the metal equilibration time-scale, production, transport, consumption, and loss. Our model finds that most galaxy metallicity gradients are in equilibrium at all redshifts. When normalized by metal diffusion, metallicity gradients are governed by the competition between radial advection, metal production, and accretion of metal-poor gas from the cosmic web. The model naturally explains the varying gradients measured in local spirals, local dwarfs, and high-redshift star-forming galaxies. We use the model to study the cosmic evolution of gradients across redshift, showing that the gradient in Milky Way-like galaxies has steepened over time, in good agreement with both observations and simulations. We also predict the evolution of metallicity gradients with redshift in galaxy samples constructed using both matched stellar masses and matched abundances. Our model shows that massive galaxies transition from the advection-dominated to the accretion-dominated regime from high to low redshifts, which mirrors the transition from gravity-driven to star formation feedback-driven turbulence. Lastly, we show that gradients in local ultraluminous infrared galaxies (major mergers) and inverted gradients seen both in the local and high-redshift galaxies may not be in equilibrium. In subsequent papers in this series, we show that the model also explains the observed relationship between galaxy mass and metallicity gradients, and between metallicity gradients and galaxy kinematics. [ABSTRACT FROM AUTHOR]

There is a growing consensus that the vast majority of ultradiffuse galaxies (UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be special in terms of their globular cluster (GC) systems. In particular, according to some authors, certain UDGs exhibit large GC populations when compared to expectations from their stellar (or total) mass. Among these special UDGs, DF44 in the Coma cluster is one of the better-known examples. DF44 has been claimed to have a relatively high number of GCs, |$N_{\mathrm{ GC}}=74^{+18}_{-18}$|⁠ , for a stellar mass of only |$3\times 10^8\, \mathrm{ M}_{ \odot}$| which would indicate a much larger dark halo mass than dwarfs of similar stellar mass. In this paper, we revisit this number and, contrary to previous results, find |$N_{\mathrm{ GC}}=21^{+7}_{-9}$| assuming that the distribution of the GCs follows the same geometry as the galaxy. If we assume that the GCs around DF44 are distributed in a (projected) circularly symmetric way and, if we use a less strict criterion for the selection of the GCs, we find |$N_{\mathrm{ GC}}=18^{+23}_{-12}$|⁠. Making use of the M GC– M halo relation, this number of GCs suggests a dark matter halo mass of |$M_{\mathrm{ halo}}=1.1^{+0.4}_{-0.5} \times 10^{11} \mathrm{ M}_{\odot}$|⁠ , a value which is consistent with the expected total mass for DF44 based on its velocity dispersion, |$\sigma =33^{+3}_{-3}$| km s−1. We conclude that the number of GCs around DF44 is as expected for regular dwarf galaxies of similar stellar mass and DF44 is not extraordinary in this respect. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the comoving megaparsec-scale intergalactic medium (IGM) environment around galaxies traced by the Lyα forest. Using our cosmological hydrodynamic simulations, we investigate the IGM–galaxy connection at z = 2 by two methods: (i) cross-correlation analysis between galaxies and the fluctuation of Lyα forest transmission (δF) and (ii) comparison of the overdensity of neutral hydrogen (H i) and galaxies. Our simulations reproduce observed cross-correlation functions (CCFs) between Lyα forest and Lyman-break galaxies. We further investigate the variation of the CCF using subsamples divided by dark matter halo mass (MDH), galaxy stellar mass (M⋆), and star formation rate (SFR) and find that the CCF signal becomes stronger with increasing MDH, M⋆, and SFR. The CCFs between galaxies and gas density fluctuation are also found to have similar trends. Therefore, the variation of δF–CCF depending on MDH, M⋆, and SFR is due to varying gas densities around galaxies. We find that the correlation between galaxies and the IGM H i distribution strongly depends on MDH as expected from linear theory. Our results support the ΛCDM paradigm, confirming a spatial correlation between galaxies and IGM H i , with more massive galaxies being clustered in higher-density regions. [ABSTRACT FROM AUTHOR]

Building accurate and flexible galaxy–halo connection models is crucial in modelling galaxy clustering on non-linear scales. Recent studies have found that halo concentration by itself cannot capture the full galaxy assembly bias effect and that the local environment of the halo can be an excellent indicator of galaxy assembly bias. In this paper, we propose an extended halo occupation distribution (HOD) model that includes both a concentration-based assembly bias term and an environment-based assembly bias term. We use this model to achieve a good fit (χ2/degrees of freedom = 1.35) on the 2D redshift-space two-point correlation function (2PCF) of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxy sample. We find that the inclusion of both assembly bias terms is strongly favoured by the data and the standard five-parameter HOD model is strongly rejected. More interestingly, the redshift-space 2PCF drives the assembly bias parameters in a way that preferentially assigns galaxies to lower mass haloes. This results in galaxy–galaxy lensing predictions that are within 1σ agreement with the observation, alleviating the perceived tension between galaxy clustering and lensing. We also showcase a consistent 3σ–5σ preference for a positive environment-based assembly bias that persists over variations in the fit. We speculate that the environmental dependence might be driven by underlying processes such as mergers and feedback, but might also be indicative of a larger halo boundaries such as the splashback radius. Regardless, this work highlights the importance of building flexible galaxy–halo connection models and demonstrates the extra constraining power of the redshift-space 2PCF. [ABSTRACT FROM AUTHOR]

In this paper, we will study the large scale structure formation using the gravitational partition function. We will assertively argue that the system of gravitating galaxies can be analyzed using the Tsallis statistical mechanics. The divergences in the Tsallis gravitational partition function can be removed using the mathematical riches of the generalization of the dimensional regularization (GDR). The finite gravitational partition function thus obtained will be used to evaluate the thermodynamics of the system of galaxies and thus, to understand the clustering of galaxies in the universe. The correlation function which is beleived to contain the information of clustering of galaxies will also be discussed in this formalism. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a method for stacking data cubelets extracted from interferometric surveys of galaxies in the redshifted 21-cm H}, i line. Unlike the traditional spectral stacking technique, which stacks one-dimensional spectra extracted from data cubes, we examine a method based on image domain stacks that makes deconvolution possible. To test the validity of this assumption, we mock a sample of 3622 equatorial galaxies extracted from the GAMA survey, recently imaged as part of a DINGO-VLA project. We first examine the accuracy of the method using a noise-free simulation and note that the stacked image and flux estimation are dramatically improved compared to traditional stacking. The extracted H  i mass from the deconvolved image agrees with the average input mass to within 3 per cent. However, with traditional spectral stacking, the derived H  i is incorrect by greater than a factor of 2. For a more realistic case of a stack with finite S/N, we also produced 20 different noise realizations to closely mimic the properties of the DINGO-VLA interferometric survey. We recovered the predicted average H  i mass to within ∼4 per cent. Compared with traditional spectral stacking, this technique extends the range of science applications where stacking can be used, and is especially useful for characterizing the emission from extended sources with interferometers. [ABSTRACT FROM AUTHOR]

The past decade has seen impressive progress in the detection of z > 7 galaxies with the Hubble Space Telescope; however, little is known about their properties. The James Webb Space Telescope will revolutionize the high-z field by providing near-IR (i.e., rest-frame optical) data of unprecedented depth and spatial resolution. Measuring galaxy quantities such as resolved stellar ages or gas metallicity gradients traditionally requires spectroscopy, as broadband imaging filters are generally too coarse to fully isolate diagnostics such as the 4000 Å (rest-frame) break, continuum emission from aged stars, and key emission lines (e.g., [O ii ], [O iii ], Hβ). However, in this paper, we show that adding NIRCam images through a strategically chosen medium-band filter to common wide-band filter sets adopted by ERS and GTO programs delivers tighter constraints on these galactic properties. To constrain the choice of filter, we perform a systematic investigation of which combinations of wide-band filters from ERS and GTO programs and single medium-band filters offer the tightest constraints on several galaxy properties at redshifts z ∼ 7–11. We employ the JAGUAR extragalactic catalogs to construct statistical samples of physically motivated mock photometry and conduct SED-fitting procedures to evaluate the accuracy of galaxy property (and photo-z) recovery with a simple star formation history model. We find that adding >4.1 μm medium filters at comparable depth to the broadband filters can significantly improve photo-zs and yield close to order-of-magnitude improvements in the determination of quantities such as stellar ages, metallicities, SF-related quantities, and emission-line fluxes at z ∼ 8. For resolved sources, the proposed approach enables the spatially resolved determination of these quantities that would be prohibitive with slit spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract—We present a database created within the project on studying edge-on galaxies. These galaxies provide a unique opportunity to study the three-dimensional distribution of the matter in galaxy disks, which is extremely important for analyzing the influence of internal and external factors on the evolution of galaxies. For the moment, extensive observed material has been accumulated on the kinematics and photometry of such galaxies. The database is designed to organize information, make it easier to visualize, and to improve works on studying this type of objects. The database combines information from previous catalogs on edge-on galaxies and data from current projects; provides access to astrometric and photometric data; carries out interconnection with other databases. The present paper describes the structure and web-access to the database: https://www.sao.ru/edgeon/. [ABSTRACT FROM AUTHOR]

Recent studies have shown that among the population of radio-loud active galactic nuclei in the local U-niverse, they numerically dominate compact radio sources of the FR0 class. In this paper, we present ob-servation results of a sample of 33 FR0 radio galaxies with RATAN-600 in the first half of 2020. For the first time, quasi-simultaneous spectra of this class objects have been measured in the frequency range as wide as 2.25–22.3 GHz. Radio luminosity of the sampled objects at the frequency 4.7 GHz varies within erg/s, with the average value of erg/s. The data confirm the deficit of extended radio emission: the average value of the core-dominance parameter () substantially exceeds the values typical for FRI galaxies. Quasi-simultaneous spectra are flat, while in the range 4.7–8.2 GHz, the average spectral index is close to zero. The spectra of 44 percent of objects which have more than three quasi-simultaneous points have peaked-shaped profiles. Using additional data of catalogs allowed us to identify three new candidates for the sources with the maximum of the spectrum in the GHz range. A statistically significant correlation was found between the parsec scale jet power and the bolometric luminosity of the accretion disk: . In general, the spectra of the studied objects are flat and have a complex structure, which indicates a high opacity in the radio range and the contribution of several components to the total spectrum. [ABSTRACT FROM AUTHOR]

This paper explores the fundamental cosmological principle, with a specific focus on the homogeneity and isotropy assumptions inherent in the Friedmann model that underpins the standard model. We propose a modified redshift model that is based on the spatial distribution of luminous matter, examining three key astronomical quantities: light intensity, number density, and the redshift of galaxies. Our analysis suggests that the model can account for cosmic accelerated expansion without the need for dark energy in the equations. Both simulations and analytical solutions reveal a unique pattern in the formation and evolution of cosmic structures, particularly in galaxy formation. This pattern shows a significant burst of activity between redshifts 0 < z < 0.4, which then progresses rapidly until approximately z ≈ 0.9, indicating that the majority of cosmic structures were formed during this period. Subsequently, the process slows down considerably, reaching a nearly constant rate until around z ≈ 1.6, after which a gradual decline begins. We also observe a distinctive redshift transition around z ≈ 0.9 before the onset of dark-matter-induced accelerated expansion. This transition is directly related to the matter density and is dependent on the geometry of the universe. The model’s ability to explain cosmic acceleration without requiring fine tuning of the cosmological constant highlights its novelty, providing a fresh perspective on the dynamic evolution of the universe.

Basing our analysis on ROGUE I, a catalog of over 32,000 radio sources associated with optical galaxies, we provide two diagnostics to select the galaxies where the radio emission is dominated by an active galactic nucleus (AGN), referred to in the paper as radio-AGNs. Each of these diagnostics can be applied independently. The first one, dubbed MIRAD, compares the flux FW3 in the W3 mid-infrared band of the Wide-field Infrared Survey Explorer telescope, with the radio flux at 1.4 GHz, F1.4. MIRAD requires no optical spectra. The second diagnostic, dubbed DLM, compares the 4000 Å break strength, Dn(4000), with the radio luminosity per unit stellar mass. The DLM diagram has already been used in the past, but not as stand-alone. For these two diagrams, we propose simple, empirical dividing lines that result in the same classification for the objects in common. These lines correctly classify as radio-AGN 99.5% of the extended radio sources in the ROGUE I catalog, and as star-forming galaxies 98%–99% of the galaxies identified as such by their emission-line ratios. Both diagrams clearly show that radio-AGNs are preferentially found among elliptical galaxies and among galaxies hosting the most massive black holes. Most of the radio sources classified as radio-AGNs in the MIRAD or DLM diagrams are either optically weak AGNs or retired galaxies. [ABSTRACT FROM AUTHOR]

We present detailed observations of photoionization conditions and galaxy kinematics in 11 z = 1.39–2.59 radio-loud quasar host galaxies. Data were taken with the OSIRIS integral field spectrograph and the adaptive optics system at the W. M. Keck Observatory that targeted nebular emission lines (Hβ, [O iii ], Hα, [N ii ]) redshifted into the near-infrared (1–2.4 μm). We detect extended ionized emission on scales ranging from 1 to 30 kpc photoionized by stars, shocks, and active galactic nuclei (AGN). Spatially resolved emission-line ratios indicate that our systems reside off the star formation and AGN-mixing sequence on the Baldwin, Phillips, & Terlevich diagram at low redshift. The dominant cause of the difference between line ratios of low-redshift galaxies and our sample is due to lower gas-phase metallicities, which are 2–5× less compared to galaxies with AGN in the nearby universe. Using gas velocity dispersion as a proxy to stellar velocity dispersion and dynamical mass measurement through inclined disk modeling, we find that the quasar host galaxies are undermassive relative to their central supermassive black hole mass, with all systems residing off the local scaling (M•–σ, M•–M*) relationship. These quasar host galaxies require substantial growth, up to an order of magnitude in stellar mass, to grow into present-day massive elliptical galaxies. Combining these results with part I of our sample paper, we find evidence for winds capable of causing feedback before the AGN host galaxies land on the local scaling relation between black hole and galaxy stellar mass, and before the enrichment of the interstellar medium to a level observed in local galaxies with AGN. [ABSTRACT FROM AUTHOR]

In the Milky Way (MW), cosmic rays (CRs) are dynamically important in the interstellar medium (ISM), contribute to hydrostatic balance, and may help regulate star formation. However, we know far less about the importance of CRs in galaxies whose gas content or star formation rate (SFR) differ significantly from those of the MW. Here, we construct self-consistent models for hadronic CR transport, losses, and contribution to pressure balance as a function of galaxy properties, covering a broad range of parameters from dwarfs to extreme starbursts. While the CR energy density increases from ∼1 eV cm−3 to ∼1 keV cm−3 over the range from sub-MW dwarfs to bright starbursts, strong hadronic losses render CRs increasingly unimportant dynamically as the SFR surface density increases. In MW-like systems, CR pressure is typically comparable to turbulent gas and magnetic pressure at the galactic mid-plane, but the ratio of CR to gas pressure drops to ∼10−3 in dense starbursts. Galaxies also become increasingly CR calorimetric and gamma-ray bright in this limit. The degree of calorimetry at fixed galaxy properties is sensitive to the assumed model for CR transport, and in particular to the time CRs spend interacting with neutral ISM, where they undergo strong streaming losses. We also find that in some regimes of parameter space hydrostatic equilibrium discs cannot exist, and in Paper II of this series we use this result to derive a critical surface in the plane of star formation surface density and gas surface density beyond which CRs may drive large-scale galactic winds. [ABSTRACT FROM AUTHOR]

Understanding the relationship between the underlying escape fraction of Lyman continuum (LyC) photons (f esc) emitted by galaxies and measuring the distribution of observed f esc values at high redshift is fundamental to the interpretation of the reionization process. In this paper, we perform a statistical exploration of the attenuation of LyC photons by neutral hydrogen in the intergalactic medium using ensembles of simulated transmission functions. We show that LyC-detected galaxies are more likely to be found in sightlines with higher than average transmission of LyC photons. This means that adopting a mean transmission at a given redshift leads to an overestimate of the true f esc for LyC-detected galaxies. We note, however, that mean values are appropriate for f esc estimates of larger parent samples that include LyC non-detected galaxies. We quantify this IGM transmission bias for LyC detections in photometric and spectroscopic surveys in the literature and show that the bias is stronger for both shallower observations and for fainter parent samples (i.e. Ly α emitters versus Lyman break galaxies). We also explore the effects of varying the underlying probability distribution function (PDF) of f esc on recovered values, showing that the underlying f esc PDF may depend on sample selection by comparing with observational surveys. This work represents a first step in improved interpretation of LyC detections in the context of understanding f esc from high-redshift galaxies. [ABSTRACT FROM AUTHOR]

In this paper, we have discussed a (1 + 9)-dimensional open cosmological model motivated from N = 2 maximal supergravity arguments characterized by the presence of a wormhole connected to the extra dimensions part and a Gauss–Bonnet (GB) curvature corrections. The universe is dominated by dark energy and cold dark matter (CDM) which emerged from extra dimensions as supported by recent phenomenological and observational arguments. By assuming that the wormhole in the outer/inner regions of the halos of galaxies is characterized by a CDM profile density, it was revealed that the universe is expanding acceleratedly with time, dominated by a microscopic traversable wormhole and dark energy. The role of the dominance of the GB term is discussed and the model is confronted with astrophysical observations. [ABSTRACT FROM AUTHOR]

We present measurements of the redshift-dependent clustering of a DESI-like luminous red galaxy (LRG) sample selected from the Legacy Survey imaging data set, and use the halo occupation distribution (HOD) framework to fit the clustering signal. The photometric LRG sample in this study contains 2.7 million objects over the redshift range of 0.4 < z < 0.9 over 5655 deg2. We have developed new photometric redshift (photo- z) estimates using the Legacy Survey DECam and WISE photometry, with σNMAD = 0.02 precision for LRGs. We compute the projected correlation function using new methods that maximize signal-to-noise ratio while incorporating redshift uncertainties. We present a novel algorithm for dividing irregular survey geometries into equal-area patches for jackknife resampling. For a five-parameter HOD model fit using the MultiDark halo catalogue, we find that there is little evolution in HOD parameters except at the highest redshifts. The inferred large-scale structure bias is largely consistent with constant clustering amplitude over time. In an appendix, we explore limitations of Markov chain Monte Carlo fitting using stochastic likelihood estimates resulting from applying HOD methods to N -body catalogues, and present a new technique for finding best-fitting parameters in this situation. Accompanying this paper, we have released the Photometric Redshifts for the Legacy Surveys catalogue of photo- z 's obtained by applying the methods used in this work to the full Legacy Survey Data Release 8 data set. This catalogue provides accurate photometric redshifts for objects with z < 21 over more than 16 000 deg2 of sky. [ABSTRACT FROM AUTHOR]

In this paper, we present an attempt to estimate the redshift evolution of the molecular to neutral gas mass ratio within galaxies (at fixed stellar mass). For a sample of five nearby grand design spirals located on the main-sequence (MS) of star-forming galaxies, we exploit maps at 500 pc resolution of stellar mass and star formation rate (M ⋆ and SFR). For the same cells, we also have estimates of the neutral (M H  i ) and molecular (⁠|$M_{\rm H_2}$|⁠) gas masses. To compute the redshift evolution, we exploit two relations: (i) one between the molecular-to-neutral mass ratio and the total gas mass (M gas), whose scatter shows a strong dependence with the distance from the spatially resolved MS, and (ii) the one between |$\log (M_{\rm {H_2}}/M_{\star })$| and log (M H  i / M ⋆). For both methods, we and that |$M_{\rm H_2}$| / M H  i within the optical radius slightly decreases with redshift, contrary to common expectations of galaxies becoming progressively more dominated by molecular hydrogen at high redshifts. We discuss possible implications of this trend on our understanding of the internal working of high-redshift galaxies. [ABSTRACT FROM AUTHOR]

Although ZwCl0024+1652 galaxy cluster at z ∼ 0.4 has been thoroughly analysed, it lacks a comprehensive study of star formation and nuclear activity of its members. With GaLAxy Cluster Evolution (GLACE) survey, a total of 174 H α emission-line galaxies (ELGs) were detected, most of them having [N  ii ]. We reduced and analysed a set of [O  iii ] and H β tunable filter (TF) observations within GLACE survey. Using H α priors, we identified [O  iii ] and H β in 35 (∼20 per cent) and 59 (∼34 per cent) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [N  ii ]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40 per cent star-forming (SF), 55 per cent composites, and 5 per cent LINERs. Star formation rate (SFR) measured through extinction corrected H α fluxes increases with stellar mass (M *), attaining its peak at |$\mathrm{\mathit{ M}}_{*}\sim 10^{9.8}\, \mathrm{M}_\odot$|⁠. We observed that the cluster centre to ∼ 1.3 Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high M *, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with M * while specific SFR (sSFR) anticorrelates with M *, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H β and/or [O  iii ] lines in ZwCl0024+1652 cluster. [ABSTRACT FROM AUTHOR]

Intrinsic alignments (IAs) of galaxies are an important contaminant for cosmic shear studies, but the modelling is complicated by the dependence of the signal on the source galaxy sample. In this paper, we use the halo model formalism to capture this diversity and examine its implications for Stage-III and Stage-IV cosmic shear surveys. We account for the different IA signatures at large and small scales, as well as for the different contributions from central/satellite and red/blue galaxies, and we use realistic mocks to account for the characteristics of the galaxy populations as a function of redshift. We inform our model using the most recent observational findings: we include a luminosity dependence at both large and small scales and a radial dependence of the signal within the halo. We predict the impact of the total IA signal on the lensing angular power spectra, including the current uncertainties from the IA best-fits to illustrate the range of possible impact on the lensing signal: the lack of constraints for fainter galaxies is the main source of uncertainty for our predictions of the IA signal. We investigate how well effective models with limited degrees of freedom can account for the complexity of the IA signal. Although these lead to negligible biases for Stage-III surveys, we find that, for Stage-IV surveys, it is essential to at least include an additional parameter to capture the redshift dependence. [ABSTRACT FROM AUTHOR]

The galaxy size–stellar mass and central surface density–stellar mass relationships are fundamental observational constraints on galaxy formation models. However, inferring the physical size of a galaxy from observed stellar emission is non-trivial due to various observational effects, such as the mass-to-light ratio variations that can be caused by non-uniform stellar ages, metallicities, and dust attenuation. Consequently, forward-modelling light-based sizes from simulations is desirable. In this work, we use the skirt   dust radiative transfer code to generate synthetic observations of massive galaxies (⁠|$M_{*}\sim 10^{11}\, \rm {M_{\odot }}$| at z  = 2, hosted by haloes of mass |$M_{\rm {halo}}\sim 10^{12.5}\, \rm {M_{\odot }}$|⁠) from high-resolution cosmological zoom-in simulations that form part of the Feedback In Realistic Environments project. The simulations used in this paper include explicit stellar feedback but no active galactic nucleus (AGN) feedback. From each mock observation, we infer the effective radius (R e), as well as the stellar mass surface density within this radius and within |$1\, \rm {kpc}$| (Σe and Σ1, respectively). We first investigate how well the intrinsic half-mass radius and stellar mass surface density can be inferred from observables. The majority of predicted sizes and surface densities are within a factor of 2 of the intrinsic values. We then compare our predictions to the observed size–mass relationship and the Σ1− M ⋆ and Σe− M ⋆ relationships. At z  ≳ 2, the simulated massive galaxies are in general agreement with observational scaling relations. At z  ≲ 2, they evolve to become too compact but still star forming, in the stellar mass and redshift regime where many of them should be quenched. Our results suggest that some additional source of feedback, such as AGN-driven outflows, is necessary in order to decrease the central densities of the simulated massive galaxies to bring them into agreement with observations at z  ≲ 2. [ABSTRACT FROM AUTHOR]

While all models for the evolution of galaxies require the accretion of gas to sustain their growth via on-going star formation, it has proven difficult to directly detect this inflowing material. In this paper we use data of nearby star-forming galaxies in the SDSS IV Mapping Nearby Galaxies at Apache Point Observatory survey to search for evidence of accretion imprinted in the chemical composition of the interstellar medium. We measure both the O/H and N/O abundance ratios in regions previously identified as having anomalously low values of O/H. We show that the unusual locations of these regions in the N/O versus O/H plane indicate that they have been created through the mixing of disk gas having higher metallicity with accreted gas having lower metallicity. Taken together with previous analysis on these anomalously low-metallicity regions, these results imply that accretion of metal-poor gas can probably sustain star formation in present-day late-type galaxies. [ABSTRACT FROM AUTHOR]

In simple models of galaxy formation and evolution, star formation is solely regulated by the amount of gas present in the galaxy. However, it has recently been shown that star formation can be suppressed by galactic dynamics in galaxies that contain a dominant spheroidal component and a low gas fraction. This 'dynamical suppression' is hypothesized to also contribute to quenching gas-rich galaxies at high redshift, but its impact on the galaxy population at large remains unclear. In this paper, we assess the importance of dynamical suppression in the context of gas regulator models of galaxy evolution through hydrodynamic simulations of isolated galaxies, with gas-to-stellar mass ratios of 0.01–0.20 and a range of galactic gravitational potentials from disc-dominated to spheroidal. Star formation is modelled using a dynamics-dependent efficiency per free-fall time, which depends on the virial parameter of the gas. We find that dynamical suppression becomes more effective at lower gas fractions and quantify its impact on the star formation rate as a function of gas fraction and stellar spheroid mass surface density. We combine the results of our simulations with observed scaling relations that describe the change of galaxy properties across cosmic time, and determine the galaxy mass and redshift range where dynamical suppression may affect the baryon cycle. We predict that the physics of star formation can limit and regulate the baryon cycle at low redshifts (z  ≲ 1.4) and high galaxy masses (M * ≳ 3 × 1010 M⊙), where dynamical suppression can drive galaxies off the star formation main sequence. [ABSTRACT FROM AUTHOR]

Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo have recently published the upper limit measurement of persistent directional stochastic gravitational-wave background (SGWB) based on data from their first and second observing runs. In this paper, we investigate whether a correlation exists between this maximal likelihood SGWB map and the electromagnetic (EM) tracers of matter structure in the Universe, such as galaxy number counts. The method we develop will improve the sensitivity of future searches for anisotropy in the SGWB and expand the use of SGWB anisotropy to probe the formation of structure in the Universe. In order to compute the cross-correlation, we used the spherical harmonic decomposition of SGWB in multiple frequency bands and converted them into pixel-based sky maps in healpix basis. For the EM part, we use the Sloan Digital Sky Survey alaxy catalogue and form healpix sky maps of galaxy number counts at the same angular resolution as the SGWB maps. We compute the pixel-based coherence between these SGWB and galaxy count maps. After evaluating our results in different SGWB frequency bands and in different galaxy redshift bins, we conclude that the coherence between the SGWB and galaxy number count maps is dominated by the null measurement noise in the SGWB maps, and therefore not statistically significant. We expect the results of this analysis to be significantly improved by using the more sensitive upcoming SGWB measurements based on the third observing run of Advanced LIGO and Advanced Virgo. [ABSTRACT FROM AUTHOR]

Context. Atomic fine structure lines have been detected in the local Universe and at high redshifts over the past decades. The [C II] emission line at 158 μm is an important observable as it provides constraints on the interstellar medium (ISM) cooling processes. Aims. We develop a physically motivated framework to simulate the production of far-infrared line emission from galaxies in a cosmological context. This first paper sets out our methodology and describes its first application: simulating the [C II] 158 μm line emission in the local Universe. Methods. We combine the output from EAGLE cosmological hydrodynamical simulations with a multi-phase model of the ISM. Gas particles are divided into three phases: dense molecular gas, neutral atomic gas, and diffuse ionised gas (DIG). We estimate the [C II] line emission from the three phases using a set of CLOUDY cooling tables. Results. Our results agree with previous findings regarding the contribution of these three ISM phases to the [C II] emission. Our model shows good agreement with the observed L[C II–star formation rate (SFR) relation in the local Universe within 0.4 dex scatter. Conclusions. The fractional contribution to the [C II] line from different ISM phases depends on the total SFR and metallicity. The neutral gas phase dominates the [C II] emission in galaxies with SFR ∼ 0.01–1 M⊙ yr−1, but the ionised phase dominates at lower SFRs. Galaxies above solar metallicity exhibit lower L[C II/SFR ratios for the neutral phase. In comparison, the L[C II/SFR ratio in the DIG is stable when metallicity varies. We suggest that the reduced size of the neutral clouds, caused by increased SFRs, is the likely cause for the L[C II deficit at high infrared luminosities, although EAGLE simulations do not reach these luminosities at z = 0. [ABSTRACT FROM AUTHOR]

We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23. [ABSTRACT FROM AUTHOR]

Machine learning techniques offer a precious tool box for use within astronomy to solve problems involving so-called big data . They provide a means to make accurate predictions about a particular system without prior knowledge of the underlying physical processes of the data. In this article, and the companion papers of this series, we present the set of Generalized Linear Models (GLMs) as a fast alternative method for tackling general astronomical problems, including the ones related to the machine learning paradigm. To demonstrate the applicability of GLMs to inherently positive and continuous physical observables, we explore their use in estimating the photometric redshifts of galaxies from their multi-wavelength photometry. Using the gamma family with a log link function we predict redshifts from the PHoto-z Accuracy Testing simulated catalogue and a subset of the Sloan Digital Sky Survey from Data Release 10. We obtain fits that result in catastrophic outlier rates as low as ∼1% for simulated and ∼2% for real data. Moreover, we can easily obtain such levels of precision within a matter of seconds on a normal desktop computer and with training sets that contain merely thousands of galaxies. Our software is made publicly available as a user-friendly package developed in Python , R and via an interactive web application. This software allows users to apply a set of GLMs to their own photometric catalogues and generates publication quality plots with minimum effort. By facilitating their ease of use to the astronomical community, this paper series aims to make GLMs widely known and to encourage their implementation in future large-scale projects, such as the Large Synoptic Survey Telescope. [ABSTRACT FROM AUTHOR]

In Paper I of this series, we presented a new N-body light-cone simulation from the MICE Collaboration, the MICE Grand Challenge (MICE-GC), containing about 70 billion dark- matter particles in a (3 h-1Gpc)³ comoving volume, from which we built halo and galaxy catalogues using a Halo Occupation Distribution and Halo Abundance Matching technique, as presented in the companion Paper II. Given its large volume and fine mass resolution, the MICE-GC simulation also allows an accurate modelling of the lensing observables from upcoming wide and deep galaxy surveys. In the last paper of this series (Paper III), we describe the construction of all-sky lensing maps, following the 'Onion Universe' approach, and discuss their properties in the light-cone up to z=1.4 with sub-arcminute spatial resolution. By comparing the convergence power spectrum in the MICE-GC to lower mass-resolution (i.e. particle mass ~1011 h-1 M⊙) simulations, we find that resolution effects are at the 5 per cent level for multipoles l ~ 10³ and 20 per cent for l ~ 104. Resolution effects have a much lower impact on our simulation, as shown by comparing the MICE-GC to recent numerical fits by Takahashi. We use the all-sky lensing maps to model galaxy lensing properties, such as the convergence, shear, and lensed magnitudes and positions, and validate them thoroughly using galaxy shear auto and cross-correlations in harmonic and configuration space. Our results show that the galaxy lensing mocks here presented can be used to accurately model lensing observables down to arcminute scales. Accompanying this series of papers, we make a first public data release of the MICE-GC galaxy mock, the MICECAT v1.0, through a dedicated web-portal for the MICE simulations, http://cosmohub.pic.es, to help developing and exploiting the new generation of astronomical surveys. [ABSTRACT FROM AUTHOR]

We study the modelling of the halo occupation distribution (HOD) for the eBOSS DR16 emission line galaxies (ELGs). Motivated by previous theoretical and observational studies, we consider different physical effects that can change how ELGs populate haloes. We explore the shape of the average HOD, the fraction of satellite galaxies, their probability distribution function (PDF), and their density and velocity profiles. Our baseline HOD shape was fitted to a semi-analytical model of galaxy formation and evolution, with a decaying occupation of central ELGs at high halo masses. We consider Poisson and sub/super-Poissonian PDFs for satellite assignment. We model both Navarro–Frenk–White and particle profiles for satellite positions, also allowing for decreased concentrations. We model velocities with the virial theorem and particle velocity distributions. Additionally, we introduce a velocity bias and a net infall velocity. We study how these choices impact the clustering statistics while keeping the number density and bias fixed to that from eBOSS ELGs. The projected correlation function, w p, captures most of the effects from the PDF and satellites profile. The quadrupole, ξ2, captures most of the effects coming from the velocity profile. We find that the impact of the mean HOD shape is subdominant relative to the rest of choices. We fit the clustering of the eBOSS DR16 ELG data under different combinations of the above assumptions. The catalogues presented here have been analysed in companion papers, showing that eBOSS RSD+BAO measurements are insensitive to the details of galaxy physics considered here. These catalogues are made publicly available. [ABSTRACT FROM AUTHOR]

Massive galaxy-scale outflows of gas are one of the most commonly invoked mechanisms to regulate the growth and evolution of galaxies throughout the universe. While the gas in outflows spans a large range of temperatures and densities, the cold molecular phase is of particular interest because molecular outflows may be capable of suppressing star formation in galaxies by removing the star-forming gas. We have conducted the first survey of molecular outflows at z > 4, targeting 11 strongly lensed dusty, star-forming galaxies (DSFGs) with high-resolution Atacama Large Millimeter/submillimeter Array observations of OH 119 μm absorption as an outflow tracer. In this first paper, we give an overview of the survey, focusing on the detection rate and structure of molecular outflows. We find unambiguous evidence for outflows in 8/11 galaxies (73%), more than tripling the number known at z > 4. This implies that molecular winds in z > 4 DSFGs must have both a near-unity occurrence rate and large opening angles to be detectable in absorption. Lensing reconstructions reveal that 500 pc scale clumpy structures in the outflows are common. The individual clumps are not directly resolved, but from optical depth arguments we expect that future observations will require 50–200 pc spatial resolution to resolve them. We do not detect high-velocity [C ii ] wings in any of the sources with clear OH outflows, indicating that [C ii ] is not a reliable tracer of molecular outflows. Our results represent a first step toward characterizing molecular outflows at z > 4 at the population level, demonstrating that large-scale outflows are ubiquitous among early massive, dusty galaxies. [ABSTRACT FROM AUTHOR]

In this paper we present a simple color–magnitude selection and obtain a large sample of 33,893 massive quiescent galaxies at intermediate redshifts (1 < z < 1.5). We choose the longest wavelength available in the Hyper-Supreme-Cam (HSC) deep survey, the Y band and i − Y color, to select the 4000 Å Balmer jump in passive galaxies to the highest redshift possible within the survey. With the rich multiwavelength data in the HSC deep fields, we then confirm that the selected galaxies are in the targeted redshift range of 1 < z < 1.5, lie in the passive region of the UVJ diagram, and have high stellar masses at log(M*/M⊙) > 10.5, with a median of log(M*/M⊙) = 11.0. A small fraction of our galaxies is also covered by the HST CANDELS. Morphological analysis in the observed H band shows that the majority of this subsample are early-type galaxies. As massive early-type galaxies trace the high-density regions in the large-scale structure in the universe, our study provides a quick and simple way to obtain a statistically significant sample of massive galaxies in a relatively narrow redshift range. Our sample is 7–20× larger at the massive end (log(M*/M⊙) > 10.5) than any existing samples obtained in previous surveys. This is a pioneer study, and the technique introduced here can be applied to a future wide-field survey to study large-scale structure and to identify high-density regions and clusters. [ABSTRACT FROM AUTHOR]

The splashback radius (R sp) of dark matter haloes has recently been detected using weak gravitational lensing and cross-correlations with galaxies. However, different methods have been used to measure R sp and to assess the significance of its detection. In this paper, we use simulations to study the precision and accuracy to which we can detect the splashback radius with 3D density, 3D subhalo, and weak lensing profiles. We study how well various methods and tracers recover R sp by comparing it with the value measured directly from particle dynamics. We show that estimates of R sp from density and subhalo profiles correspond to different percentiles of the underlying R sp distribution of particle orbits. At low accretion rates, a second caustic appears and can bias results. Finally, we show that upcoming lensing surveys may be able to constrain the R sp–Γdyn relation directly. [ABSTRACT FROM AUTHOR]

In the first part of this article we expand three fundamental aspects of the methodology connected to the determination of a relation among the spatial density and the gravitational potential that can be specialized to distinct mass density agglomerations. As a consequence, we obtain general relations for the diagonal entries of a square symmetric matrix without zeros, we provide an expression of the gravitational potential, suitable, to represent several different mass density configurations, and we determine relations for the semi-axes of a triaxial spheroidal mass distribution, as a function of the spheroid mass density, volume density, and radius. In the second part of this paper, we employ the tools developed in the first part, to analyse the mass density content and the inner and global structure of the dark matter haloes of UGC 8490 and UGC 9753, through the fits to the dark matter rotation curves of the two galaxies, assuming a triaxial spheroidal dark matter mass configuration. We employ the Navarro Frenk and White, Burkert, DiCintio, Einasto and Stadel dark matter models, and we obtain that both a cored Burkert and cuspy DiCintio and Navarro Frenk and White inward dark matter distributions could represent equally well the observed data, furthermore we determine an oblate spheroidal dark matter mass density configuration for UGC 8490 and UGC 9753. The latter outcome is confirmed by the estimation of the gravitational torques exerted by the dark matter halo of each analysed galaxy, on the corresponding baryonic components. [ABSTRACT FROM AUTHOR]

Context. Lyman-α (Lyα) is the brightest emission line in star-forming galaxies. However, its interpretation in terms of physical properties is hampered by the resonant nature of Lyα photons. In order to remedy this complicated situation, the Lyman Alpha Reference Sample (LARS) was defined, enabling the study of Lyα production and escape mechanisms in 14 local star-forming galaxies. Aims. With this paper, we complement our efforts and study the global dust and (molecular) gas content as well as the properties of gas associated with photon-dominated regions. We aim to characterize the interstellar medium of LARS galaxies, allowing us to relate these newly derived properties to quantities relevant for Lyα escape. Methods. We observed LARS galaxies with Herschel, SOFIA, the IRAM 30m telescope, and APEX, targeting far-infrared (FIR) continuum and emission lines of [C II]158 μm, [O I]63 μm, [O III]88 μm, and low-J CO lines. Using Bayesian methods we derived dust model parameters and estimated the total gas masses for all LARS galaxies, taking into account a metallicity-dependent gas-to-dust ratio. Star formation rates were estimated from FIR, [C II]158 μm, and [O I]63 μm luminosities. Results. LARS covers a wide dynamic range in the derived properties, with FIR-based star formation rates from ∼0.5−100 M⊙ yr−1, gas fractions between ∼15−80%, and gas depletion times ranging from a few hundred megayears up to more than ten gigayears. The distribution of LARS galaxies in the Σgas versus ΣSFR (Kennicutt–Schmidt plane) is thus quite heterogeneous. However, we find that LARS galaxies with the longest gas depletion times, that is, relatively high gas surface densities (Σgas) and low star formation rate densities (ΣSFR), have by far the highest Lyα escape fraction. A strong approximately linear relation is found between the Lyα escape fraction and the total gas (HI+H2) depletion time. We argue that the Lyα escape in those galaxies is driven by turbulence in the star-forming gas that shifts the Lyα photons out of resonance close to the places where they originate. We further report on an extreme [C II]158 μm excess in LARS 5, corresponding to ∼14 ± 3% of the FIR luminosity, which probably is the most extreme [C II]-to-FIR ratio observed in a galaxy (without active nucleus) to date. [ABSTRACT FROM AUTHOR]

Theoretical models suggest that galaxy mergers may have profoundly shaped galaxy morphologies through cosmic time. However, observational estimates of galaxy pair fractions, and implied galaxy mergers, still do not converge, suggesting different numbers and redshift evolution. This paper explores the connection between stellar mass estimation and the pair fraction of galaxies using |$\rm {\small STEEL}$|⁠ , the Statistical sEmi-Emprical modeL, in which galaxies are mapped on to host dark matter haloes via a stellar mass–halo mass (SMHM) relation. As haloes of different mass are predicted to undergo, on average, different degrees of mergers, we expect that galaxy merger rates at fixed stellar mass will also vary depending on the shape of the input SMHM relation. Using a variety of input SMHM relations, also including one that matches the outputs of the Illustris TNG simulation, we thoroughly explore how systematic variations in the stellar mass functions propagate on to the normalization and redshift dependence of the galaxy pair fraction. We find that (i) stellar mass functions characterized by larger number densities of massive galaxies and thus a steeper SMHM relation, result in a substantial reduction of the pair fractions of massive galaxies; (ii) a time-varying SMHM relation produces galaxy pair fractions that can have varied redshift evolutions. We argue that in a hierarchical, dark matter dominated Universe, stellar mass estimates are a considerable cause of bias that must be accounted for when comparing pair fractions from different data sets or from theoretical models developed independently of the fitted survey data. [ABSTRACT FROM AUTHOR]

Cross-correlations between galaxy weak lensing (WL) and cosmic microwave background (CMB) lensing are powerful tools to probe matter fluctuations at intermediate redshifts and to detect residual systematics in either probe. In this paper, we study the cross-correlation of galaxy WL from the Hyper Suprime-Cam Subaru Strategic Program (HSC) first data release and CMB lensing from the final Planck data release, for HSC source galaxies at 0.3 ≤ z ≤ 1.5. HSC is the deepest Stage-III galaxy WL survey, and provides a great opportunity to study the high-redshift universe. It also presents new challenges related to its exceptionally high source density, such as source blending. The cross-correlation signal is measured at a significance level of 3.1σ. The amplitude of our best-fit model with respect to the best-fit 2018 Planck cosmology is A = 0.81 ± 0.25, consistent with A = 1. Our result is also consistent with previous CMB lensing and galaxy WL cross-correlation studies using different surveys. We perform tests with respect to the WL B-modes, the point-spread-function, photometric redshift errors, and thermal Sunyaev–Zel'dovich leakage, and find no significant evidence of residual systematics. [ABSTRACT FROM AUTHOR]

Whereas cold dark matter (CDM) simulations predict central dark matter cusps with densities that diverge as ρ(r) ∼ 1/r, observations often indicate constant-density cores with finite central densities ρ0 and a flat density distribution within a core radius r0. This paper investigates whether this core–cusp problem can be solved by fuzzy dark matter (FDM), a hypothetical particle with a mass of the order of m ≈ 10−22 eV and a corresponding de Broglie wavelength on astrophysical scales. We show that galaxies with CDM halo virial masses Mvir ≤ 1011M⊙ follow two core-scaling relations. In addition to the well-known universal core column density Σ0 ≡ ρ0 × r0 = 75 pc−2, core radii increase with virial masses as r0 ∼ with γ of order unity. Using the simulations by Schive et al. we demonstrate that FDM can explain the r0–Mvir scaling relation if the virial masses of the observed galaxy sample scale with the formation redshift z as Mvir ∼ (1 + z)−0.4. The observed constant Σ0 is however in complete disagreement with FDM cores which are characterized by a steep dependence Σ0 ∼ r , independent of z. More high-resolution simulations are now required to confirm the simulations of Schive et al. and explore the transition region between the soliton core and the surrounding halo. If these results hold, FDM can be ruled out as the origin of observed dark matter cores and other physical processes are required to account for their formation. [ABSTRACT FROM AUTHOR]