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We measure the clustering of low-redshift Sloan Digital Sky Survey (SDSS) galaxies as a function of stellar mass (⁠|$10.0\lt \log (M_*/\mathrm{M}_\odot)\lt 11.5$|⁠) and specific star formation rate (sSFR) and compare the results to models of the galaxy–halo connection. We find that the autocorrelation functions of central galaxies exhibit little dependence on sSFR, with the well-known stronger clustering of quiescent galaxies mainly attributable to satellites. Because halo assembly history is known to affect distinct halo clustering, this result implies that there is little net correlation between halo assembly history and central galaxy sSFR. However, cross-correlations with satellites are stronger for quiescent centrals than star-forming centrals, consistent with quiescent centrals having more satellites in their haloes at fixed |$M_*$|⁠ , as found in SDSS group catalogues. We model the galaxy–halo connection in an N -body simulation by assigning sSFRs to central galaxies in three different ways. Two of the models depend on halo assembly history (being based on halo accretion rate or concentration), while the third is independent of halo assembly history (being based on peak halo circular velocity, |$V_\text{peak}$|⁠ , a proxy for halo mass). All three models replicate the observed autocorrelations of central galaxies, while only the |$V_\text{peak}$| model reproduces the observed cross-correlations with satellites. This further suggests that the effects of halo assembly history may not be easily seen in autocorrelations of centrals and implies that a more complete understanding of central galaxy clustering may require more than autocorrelations of centrals alone. Additionally, the good agreement with the |$V_\text{peak}$| model supports the idea that quiescent central galaxies reside in more massive haloes than star-forming central galaxies at fixed |$M_*$|⁠. [ABSTRACT FROM AUTHOR]

We investigate the relation between galaxy structure and star formation rate (SFR) in a sample of |$\sim 2.9\times 10^{4}$| central galaxies with |$z\lt 0.0674$| and axial ratios |$b/a\gt 0.5$|⁠. The star-forming main sequence (SFMS) shows a bend around the stellar mass of |$M_\ast \le {}M_c=2\times 10^{10}{}{\rm M}_{\odot }$|⁠. At |$M_\ast \le {}M_c$|⁠ , the SFMS follows a power-law |$\text{SFR}\propto {}M_\ast ^{0.85}$|⁠ , while at higher masses it flattens. |$M_c$| corresponds to a dark matter halo mass of |$M_\text{vir}\sim {}10^{11.8}{\rm M}_{\odot }$| where virial shocks occurs. Some galaxy structure (e.g. half-light radius, |$R_e$|⁠) exhibits a non-monotonic dependence across the SFMS at a fixed |$M_\ast$|⁠. We find |$\text{SFR}\propto {R_e^{-0.28}}$| at fixed |$M_\ast$|⁠ , consistent with the global Kennicutt–Schmidt (KS) law. This finding suggests that galaxy sizes contribute to the scatter of the SFMS. However, at |$M_\ast \gt M_c$| the relationship between SFR and |$R_e$| diminishes. Low-mass galaxies above the mean of the SFMS have smaller radii, exhibit compact and centrally concentrated profiles resembling green valley (GV) and quiescent galaxies at the same mass, and have higher |$M_{\text{H}_2}{/}M_\rm{H\,{\small I}}$|⁠. Conversely, those below the SFMS exhibit larger radii, lower densities, have no GV or quiescent counterparts at their mass and have lower |$M_{\text{H}_2}/M_\rm{H\,{\small I}}$|⁠. The above data suggest two pathways for quenching low-mass galaxies, |$M_\ast \le {}M_c$|⁠ : a fast one that changes the morphology on the SFMS and a slow one that does not. Above |$M_c$|⁠ , galaxies below the SFMS resemble GV and quiescent galaxies structurally, implying that they undergo a structural transformation already within the SFMS. For these massive galaxies, CG are strongly bimodal, with SFMS galaxies exhibiting negative colour gradients, suggesting most star formation occurs in their outskirts, maintaining them within the SFMS. [ABSTRACT FROM AUTHOR]

We present a new cosmologically motivated mock redshift survey of the dusty star-forming galaxy population. Our mock survey is based on the Bolshoi– Planck dark matter halo simulation and covers an area of 5.3 deg2. Using a semi-empirical approach, we generate a light-cone and populate the dark matter haloes with galaxies. Infrared properties are assigned to the galaxies based on theoretical and empirical relations from the literature. Additionally, background galaxies are gravitationally lensed by dark matter haloes along the line of sight assuming a point-mass model approximation. We characterize the mock survey by measuring the star formation rate density, integrated number counts, redshift distribution, and infrared luminosity function. When compared with single-dish and interferometric observations, the predictions from our mock survey closely follow the compiled results from the literature. We have also directed this study towards characterizing one of the extragalactic legacy surveys to be observed with the TolTEC camera at the Large Millimeter Telescope: the 0.8 sq. degree Ultra Deep Survey, with expected depths of 0.025, 0.018, and 0.012 mJy beam−1 at 1.1, 1.4, and 2.0 mm. Exploiting the clustering information in our mock survey, we investigate its impact on the effect of flux boosting by the fainter population of dusty galaxies, finding that clustering can increase the median boosting by 0.5  per cent at 1.1 mm, 0.8  per cent at 1.4 mm, and 2.0  per cent at 2.0 mm, and with higher dispersion. [ABSTRACT FROM AUTHOR]

Using spatially resolved fossil record analysis on a large sample of 'red and dead' elliptical galaxies (classical ellipticals, CLEs) from the MaNGA/SDSS-IV DR15 survey, we reconstruct the archaeological evolution of their radial gradients in mass-to-luminosity ratio (M / L), g − r colour, and specific star formation (SF) rate. We also calculate other metrics that quantify the inside-out SF quenching and external mass growth processes. The M / L gradients, ∇Υ⋆, are approximately flat at high look-back times (t lb), but then they become negative and steeper until an epoch, when this trend reverses. These trends are shifted to later epochs the less massive the galaxies are. Colour gradients follow qualitatively similar trends. We find that these trends are mainly driven by strong inside-out quenching, without significant outer growth or structural changes overall. Our results suggest a scenario where the main progenitors of local CLE galaxies evolved quasi-passively after an early dissipative phase, but underwent radial photometric changes due to the inside-out quenching that led to the systematic decrease of ∇Υ⋆ and to an increase of the light-weighted radius. The late reversing of ∇Υ⋆, t lb≈2 − 4 Gyr, roughly coincides with the global quenching of the CLE galaxies. We have pushed archaeological inferences to the limit, but thanks to the large number of objects and an understanding of how the caveats and assumptions affect our results, we conclude that they offer an average description of evolutionary behaviours of CLE progenitors that is valid at least qualitatively. [ABSTRACT FROM AUTHOR]

We investigate the formation of brightest cluster galaxies (BCGs) in the TNG300 cosmological simulation of the IllustrisTNG project. Our cluster sample consists of 700 haloes with |$M_{\rm 200}\ge 5 \times 10^{13} \, {\rm M}_{\odot }$| at z  = 0, along with their progenitors at earlier epochs. This includes 280 systems with |$M_{\rm 200}\ge 10^{14} \, {\rm M}_{\odot }$| at z  = 0, as well as three haloes with |$M_{\rm 200}\ge 10^{15} \, {\rm M}_{\odot }$|⁠. We find that the stellar masses and star formation rates of our simulated BCGs are in good agreement with observations at z ≲ 0.4, and that they have experienced, on average, ∼2 (∼3) major mergers since z  = 1 (z  = 2). Separating the BCG from the intracluster light (ICL) by means of a fixed 30 kpc aperture, we find that the fraction of stellar mass contributed by ex situ (i.e. accreted) stars at z  = 0 is approximately 70, 80, and 90 per cent for the BCG, BCG + ICL, and ICL, respectively. Tracking our simulated BCGs back in time using the merger trees, we find that they became dominated by ex situ stars at z ∼1–2, and that half of the stars that are part of the BCG at z  = 0 formed early (z ∼ 3) in other galaxies, but 'assembled' onto the BCG until later times (z ≈ 0.8 for the whole sample, z ≈ 0.5 for BCGs in |$M_{\rm 200}\ge 5 \times 10^{14} \, {\rm M}_{\odot }$| haloes). Finally, we show that the stellar mass profiles of BCGs are often dominated by ex situ stars at all radii, with stars from major mergers being found closer to the centre, while stars that were tidally stripped from other galaxies dominate the outer regions. [ABSTRACT FROM AUTHOR]

The stochastic order redshift technique (sort) is a simple, efficient, and robust method to improve cosmological redshift measurements. The method relies upon having a small (∼10 per cent) reference sample of high-quality redshifts. Within pencil-beam-like sub-volumes surrounding each galaxy, we use the precise d N /d z distribution of the reference sample to recover new redshifts and assign them one-to-one to galaxies such that the original rank order of redshifts is preserved. Preserving the rank order is motivated by the fact that random variables drawn from Gaussian probability density functions with different means but equal standard deviations satisfy stochastic ordering. This process is repeated for sub-volumes surrounding each galaxy in the survey. This results in every galaxy being assigned multiple 'recovered' redshifts from which a new redshift estimate is determined. An earlier paper applied sort to a mock Sloan Digital Sky Survey at z ≲ 0.2 and accurately recovered the two-point correlation function (2PCF) on scales ≳ 4  h −1Mpc. In this paper, we test the performance of sort in surveys spanning the redshift range 0.75 < z < 2.25. We used two mock surveys extracted from the Small MultiDark–Planck and Bolshoi–Planck N -body simulations with dark matter haloes that were populated by the Santa Cruz semi-analytic model. We find that sort overall improves redshift estimates, accurately recovers the redshift-space 2PCF ξ(s) on scales ≳ 2.5  h −1Mpc, and provides improved local density estimates in regions of average or higher density, which may allow for improved understanding of how galaxy properties relate to their environments. [ABSTRACT FROM AUTHOR]

We apply stellar population synthesis analysis to obtain spatially resolved archaeological inferences for a large sample of 'red and dead' Elliptical galaxies (Classical Ellipticals, CLEs) from the MaNGA/SDSS-IV DR15 survey. From their 2D stellar light and mass maps, we explore the differences between the radial mass and light distributions in the rest-frame bands g ,  r , and i as functions of look-back time, t lb, or redshift, z. We characterize these differences through the ratios between the following mass- and light-derived global properties: sizes, concentrations, and effective surface densities. We find that the mass-to-light ratios of these properties change with t lb, more the more massive the galaxies are. The CLE galaxy archaeological progenitors are, on average, less compact, concentrated, and dense in light than in mass as z decreases. However, at later times, when also the evolution of the progenitors becomes passive at all radii, there is an upturn in these trends and the differences between mass and light in compactness/concentration decrease towards z ∼ 0. The trends in the ratios of mass-to-light sizes agree qualitatively with results from direct observations in galaxy surveys at different redshifts. We discuss the caveats and interpretations of our results, and speculate that the strong structural evolution found in some previous studies for early-type galaxies could be explained partially by photometric changes rather than by intrinsic structural changes. [ABSTRACT FROM AUTHOR]

We characterize the conditional distributions of the H  i gas-to-stellar mass ratio, |$\mbox{$R_{\rm H\,\rm{i}}$}\equiv \mbox{$M_{\rm H\,\rm{i}}$}/\mbox{$M_{\ast }$}$|⁠ , given the stellar mass, M *, of local galaxies from M * ∼ 107–1012 M⊙ separated into centrals and satellites as well as into late- and early-type galaxies (LTGs and ETGs, respectively). To do so, we use (1) the homogeneous 'eXtended GALEX Arecibo SDSS Survey', xGASS (Catinella et al. 2018), by re-estimating their upper limits and taking into account them in our statistical analysis; and (2) the results from a large compilation of H  i data reported in Calette et al. (2018). We use the |$R_{\rm H\,\rm{i}}$| conditional distributions combined with the Galaxy Stellar Mass Function to infer the bivariate |$M_{\rm H\,\rm{i}}$| and M * distribution of all galaxies as well of the late/early-type and central/satellite subsamples and their combinations. Satellites are on average less H  i gas-rich than centrals at low and intermediate masses, with differences being larger for ETGs than LTGs; at M * > 3−5 × 1010 M⊙ the differences are negligible. The differences in the H  i gas content are much larger between LTGs and ETGs than between centrals and satellites. Our empirical H  i Mass Function is strongly dominated by central galaxies at all masses. The empirically constrained bivariate |$M_{\rm H\,\rm{i}}$| and M * distributions presented here can be used to compare and constrain theoretical predictions as well as to generate galaxy mock catalogues. [ABSTRACT FROM AUTHOR]

This paper studies pseudo-bulges (P-bulges) and classical bulges (C-bulges) in Sloan Digital Sky Survey (SDSS) central galaxies using the new bulge indicator ΔΣ1, which measures relative central stellar-mass surface density within 1 kpc. We compare ΔΣ1 to the established bulge-type indicator Δ〈μe〉 from Gadotti (2009) and show that classifying by ΔΣ1 agrees well with Δ〈μe〉. ΔΣ1 requires no bulge–disc decomposition and can be measured on SDSS images out to z  = 0.07. Bulge types using it are mapped on to 20 different structural and stellar-population properties for 12 000 SDSS central galaxies with masses 10.0 < log M */M⊙ < 10.4. New trends emerge from this large sample. Structural parameters show fairly linear log–log relations versus ΔΣ1 and Δ〈μe〉 with only moderate scatter, while stellar-population parameters show a highly non-linear 'elbow' in which specific star formation rate remains roughly flat with increasing central density and then falls rapidly at the elbow, where galaxies begin to quench. P-bulges occupy the low-density end of the horizontal arm of the elbow and are universally star forming, while C-bulges occupy the elbow and the vertical branch and exhibit a wide range of star formation rates at a fixed density. The non-linear relation between central density and star formation rate has been seen before, but this mapping on to bulge class is new. The wide range of star formation rates in C-bulges helps to explain why bulge classifications using different parameters have sometimes disagreed in the past. The elbow-shaped relation between density and stellar indices suggests that central structure and stellar populations evolve at different rates as galaxies begin to quench. [ABSTRACT FROM AUTHOR]

We study the global star formation rate (SFR) versus stellar mass (M *) correlation, and the spatially resolved SFR surface density (ΣSFR) versus stellar mass surface density (Σ*) correlation, in a sample of ∼2000 galaxies from the MaNGA MPL-5 survey. We classify galaxies and spatially resolved areas into star forming and retired according to their ionization processes. We confirm the existence of a star-forming main sequence (SFMS) for galaxies and spatially resolved areas, and show that they have the same nature, with the global as a consequence of the local one. The latter presents a bend below a limit Σ* value, ≈3 × 107 M |$\odot$|  kpc−2, which is not physical. Using only star-forming areas (SFAs) above this limit, a slope and a scatter of ≈1 and ≈0.27 dex are determined. The retired galaxies/areas strongly segregate from their respective SFMSs, by ∼−1.5 dex on average. We explore how the global/local SFMSs depend on galaxy morphology, finding that for star-forming galaxies and SFAs, there is a trend to lower values of star formation activity with earlier morphological types, which is more pronounced for the local SFMS. The morphology not only affects the global SFR due to the diminish of SFAs with earlier types, but also affects the local SF process. Our results suggest that the local SF at all radii is established by some universal mechanism partially modulated by morphology. Morphology seems to be connected to the slow aging and sharp decline of the SF process, and on its own it may depend on other properties as the environment. [ABSTRACT FROM AUTHOR]

We investigate the dependence of the galaxy–halo connection and galaxy density field in modified gravity models using the N -body simulations for f (R) and nDGP models at z  = 0. Because of the screening mechanisms employed by these models, chameleon and Vainshtein, haloes are clustered differently in the non-linear regime of structure formation. We quantify their deviations in the galaxy density field from the standard Λ cold dark matter (ΛCDM) model under different environments. We populate galaxies in haloes via the (sub)halo abundance matching. Our main results are as follows: (1) The galaxy–halo connection strongly depends on the gravity model; a maximum variation of |${\sim }40{{\ \rm per\ cent}}$| is observed between halo occupational distribution (HOD) parameters; (2) f (R) gravity models predict an excess of galaxies in low-density environments of |${\sim }10{{\ \rm per\ cent}}$| but predict a deficit of |${\sim }10{{\ \rm per\ cent}}$| at high-density environments for | f R 0| = 10−4 and 10−6 while | f R 0| = 10−5 predicts more high-density structures; nDGP models are consistent with ΛCDM; (3) different gravity models predict different dependences of the galaxy luminosity function (GLF) with the environment, especially in void-like regions we find differences around |${\sim }10{{\ \rm per\ cent}}$| for the f (R) models while nDPG models remain closer to ΛCDM for low-luminosity galaxies but there is a deficit of |${\sim }11{{\ \rm per\ cent}}$| for high-luminosity galaxies in all environments. We conclude that the dependence of the GLF with environment might provide a test to distinguish between gravity models and their screening mechanisms from the ΛCDM. We provide HOD parameters for the gravity models analysed in this paper. [ABSTRACT FROM AUTHOR]

By means of post-processed cosmological hydrodynamics simulations, we explore the ability of the fossil record method to recover the stellar mass, age gradients, and global/radial star formation and mass growth histories of galaxies observed with an optical Integral Field Unity (IFU). We use two simulations of representative Milky Way-sized galaxies, one disc-dominated and another bulge-dominated. We generate data cubes emulating MaNGA/SDSS-IV instrumental and observational conditions, and analyze them using the Pipe3D pipeline. For optimal MaNGA instrumental/observational set-ups, the global masses, ages, and dust extinctions of both galaxies are well recovered within the uncertainties, while for the radial distributions, the trend is to get slightly flatter age gradients and weaker inside-out growth modes than the true ones. The main bias is in recovering younger stellar populations in the inner, older regions, and slightly older stellar populations in the outer, younger regions, as well as lower global stellar masses. These trends are enhanced as lower is the spatial sampling/resolution (less number of fibres), more inclined and dust-attenuated is the observed galaxy, lower is the signal-to-noise ratio, and worse is the seeing. The recovered properties and histories are more affected for the disc-dominated galaxy with a prominent inside-out growth mode than for the bulge-dominated galaxy assembled earlier and more coherently. We make publicly available the code and the mock IFU datacubes used in this paper. [ABSTRACT FROM AUTHOR]

We present the results of the archaeological analysis of the stellar populations of a sample of ∼4000 galaxies observed by the SDSS-IV MaNGA survey using pipe3d. Based on this analysis we extract a sample of ∼150 000 star formation rates (SFRs) and stellar masses that mimic a single cosmological survey covering the redshift range between |$z$| ∼ 0 and |$z$| ∼ 7. We confirm that the star-forming main sequence holds as a tight relation in this range of redshifts, evolving in both the zero-point and slope. This evolution is different for local star-forming (SFGs) and retired (RGs) galaxies, with the latter presenting a stronger evolution in the zero-point and a weaker evolution in the slope. The fraction of RGs decreases rapidly with |$z$|⁠, particularly for RGs at |$z$| ∼ 0. We detect RGs well above |$z$| > 1, although not all of them are progenitors of local RGs. Finally, adopting the required corrections to make the survey complete in mass in a limited volume, we recover the cosmic SFR, stellar-mass density, and average specific SFR histories of the Universe in this wide range of look-back times. Our derivations agree with those reported by various cosmological surveys. We demonstrate that the progenitors of local RGs were more actively forming stars in the past, contributing to most of the cosmic SFR density at |$z$| > 0.5, and to most of the cosmic stellar-mass density at any redshift. They suffer a general quenching in the SFR at z ∼  0.35. Below this redshift the progenitors of local SFGs dominate the SFR density of the Universe. [ABSTRACT FROM AUTHOR]

We study the properties of distinct dark matter haloes (i.e. those that are not subhaloes) that have a final virial mass |$\rm{M_{\rm vir}}$| at |$z$| = 0 less than their peak mass (⁠|$\rm{M_{\rm peak}}$|⁠) in the Bolshoi–Planck cosmological simulation. We identify two primary causes of halo mass-loss: relaxation after a major merger and tidal stripping by a massive neighbouring halo. Major mergers initially boost |$\rm{M_{\rm vir}}$| and typically cause the final halo to become more prolate and less relaxed and to have higher spin and lower NFW concentration. As the halo relaxes, high-energy material from the recent merger gradually escapes beyond the virial radius, temporarily resulting in a net negative accretion rate that reduces the halo mass by |$5{\hbox{-}}15{{\ \rm per\ cent}}$| on average. Haloes that experience a major merger around |$z$| = 0.4 typically reach a minimum mass near |$z$| = 0. Tidal stripping mainly occurs in dense regions, and it causes haloes to become less prolate and have lower spins and higher NFW concentrations. Tidally stripped haloes often lose a large fraction of their peak mass (⁠|${\gt}20{{\ \rm per\ cent}}$|⁠) and most never recover (or even re-attain a positive accretion rate). Low-mass haloes can be strongly affected by both post-merger mass-loss and tidal stripping, while high-mass haloes are predominantly influenced by post-merger mass-loss and show few signs of significant tidal stripping. [ABSTRACT FROM AUTHOR]

We used ionized gas and stellar kinematics for 667 spatially resolved galaxies publicly available from the Calar Alto Legacy Integral Field Area survey (CALIFA) third Data Release with the aim of studying kinematic scaling relations as the Tully & Fisher (TF) relation using rotation velocity, Vrot, the Faber & Jackson (FJ) relation using velocity dispersion, σ, and also a combination of Vrot and σ through the SK parameter defined as $S_{K}^2 = KV_{rot}^2 + \sigma ^2$ with constant K. Late-type and early-type galaxies reproduce the TF and FJ relations. Some early-type galaxies also follow the TF relation and some late-type galaxies the FJ relation, but always with larger scatter. On the contrary, when we use the SK parameter, all galaxies, regardless of the morphological type, lie on the same scaling relation, showing a tight correlation with the total stellar mass, M⋆. Indeed, we find that the scatter in this relation is smaller or equal to that of the TF and FJ relations. We explore different values of the K parameter without significant differences (slope and scatter) in our final results with respect to the case K= 0.5 besides a small change in the zero-point. We calibrate the kinematic $S_{K}^2$ dynamical mass proxy in order to make it consistent with sophisticated published dynamical models within 0.15 dex. We show that the SK proxy is able to reproduce the relation between the dynamical mass and the stellar mass in the inner regions of galaxies. Our result may be useful in order to produce fast estimations of the central dynamical mass in galaxies and to study correlations in large galaxy surveys. [ABSTRACT FROM AUTHOR]

(Sub)halo abundance matching (SHAM) assumes that one (sub) halo property, such as mass Mvir or peak circular velocity Vpeak, determines properties of the galaxy hosted in each (sub) halo such as its luminosity or stellar mass. This assumption implies that the dependence of galaxy luminosity functions (GLFs) and the galaxy stellar mass function (GSMF) on environmental density is determined by the corresponding halo density dependence. In this paper, we test this by determining from a Sloan Digital Sky Survey sample the observed dependence with environmental density of the ugriz GLFs and GSMF for all galaxies, and for central and satellite galaxies separately. We then show that the SHAM predictions are in remarkable agreement with these observations, even when the galaxy population is divided between central and satellite galaxies. However, we show that SHAM fails to reproduce the correct dependence between environmental density and g - r colour for all galaxies and central galaxies, although it better reproduces the colour dependence on environmental density of satellite galaxies. [ABSTRACT FROM AUTHOR]

We present a simple, efficient and robust approach to improve cosmological redshift measurements. The method is based on the presence of a reference sample for which a precise redshift number distribution (dN/dz) can be obtained for different pencil-beam-like sub-volumes within the original survey. For each sub-volume we then impose that: (i) the redshift number distribution of the uncertain redshift measurements matches the reference dN/dz corrected by their selection functions and (ii) the rank order in redshift of the original ensemble of uncertain measurements is preserved. The latter step is motivated by the fact that random variables drawn from Gaussian probability density functions (PDFs) of different means and arbitrarily large standard deviations satisfy stochastic ordering. We then repeat this simple algorithm for multiple arbitrary pencil-beam-like overlapping sub-volumes; in this manner, each uncertain measurement has multiple (non-independent) 'recovered' redshifts which can be used to estimate a new redshift PDF. We refer to this method as the Stochastic Order Redshift Technique (SORT). We have used a state-of-the-art N-body simulation to test the performance of SORT under simple assumptions and found that it can improve the quality of cosmological redshifts in a robust and efficient manner. Particularly, SORT redshifts (zsort) are able to recover the distinctive features of the so-called 'cosmic web' and can provide unbiased measurement of the two-point correlation function on scales ≳4 h-1Mpc. Given its simplicity, we envision that a method like SORT can be incorporated into more sophisticated algorithms aimed to exploit the full potential of large extragalactic photometric surveys. [ABSTRACT FROM AUTHOR]

We present new determinations of the stellar-to-halo mass relation (SHMR) at z = 0-10 that match the evolution of the galaxy stellar mass function, the star formation rate (SFR)-M* relation and the cosmic SFR. We utilize a compilation of 40 observational studies from the literature and correct them for potential biases. Using our robust determinations of halo mass assembly and the SHMR, we infer star formation histories, merger rates and structural properties for average galaxies, combining star-forming and quenched galaxies. Our main findings are as follows: (1) The halo mass M50 above which 50 per cent of galaxies are quenched coincides with sSFR/sMAR ~ 1, where sSFR is the specific SFR and sMAR is the specific halo mass accretion rate. (2) M50 increases with redshift, presumably due to cold streams being more efficient at high redshifts, while virial shocks and active galactic nucleus feedback become more relevant at lower redshifts. (3) The ratio sSFR/sMAR has a peak value, which occurs around Mvir ~ 2 × 1011 M⊙. (4) The stellar mass density within 1 kpc, Σ1, is a good indicator of the galactic global sSFR. (5) Galaxies are statistically quenched after they reach a maximum in Σ1, consistent with theoretical expectations of the gas compaction model; this maximum depends on redshift. (6) In-situ star formation is responsible for most galactic stellar mass growth, especially for lower mass galaxies. (7) Galaxies grow inside-out. The marked change in the slope of the size-mass relation when galaxies became quenched, from d log Reff/d logM* ~ 0.35 to ~2.5, could be the result of dry minor mergers. [ABSTRACT FROM AUTHOR]

We report and provide fitting functions for the abundance of dark matter halos and subhalos as a function of mass, circular velocity, and redshift from the new Bolshoi-Planck and MultiDark-Planck ΛCDM cosmological simulations, based on the Planck cosmological parameters. We also report the halo mass accretion rates, which may be connected with galaxy star formation rates. We show that the higher cosmological matter density of the Planck parameters compared with the WMAP parameters leads to higher abundance of massive halos at high redshifts. We find that the median halo spin parameter λB=J(√2MvirRvirVvir)−1 is nearly independent of redshift, leading to predicted evolution of galaxy sizes that is consistent with observations, while the significant decrease with redshift in median λP=J|E|−1/2G−1M−5/2 predicts more decrease in galaxy sizes than is observed. Using the Tully-Fisher and Faber-Jackson relations between galaxy velocity and mass, we show that a simple model of how galaxy velocity is related to halo maximum circular velocity leads to increasing overprediction of cosmic stellar mass density as redshift increases beyond redshifts z∼1, implying that such velocity-mass relations must change at redshifts z ≳ 1. By making a realistic model of how observed galaxy velocities are related to halo circular velocity, we show that recent optical and radio observations of the abundance of galaxies are in good agreement with our ΛCDM simulations. Our halo demographics are based on updated versions of the \rockstar\ and \ctrees\ codes, and this paper includes appendices explaining all of their outputs. This paper is an introduction to a series of related papers presenting other analyses of the Bolshoi-Planck and MultiDark-Planck simulations. [ABSTRACT FROM AUTHOR]

The galaxy stellar-to-halo mass relation (SHMR) is nearly time-independent for z < 4. We therefore construct a time-independent SHMR model for central galaxies, wherein the in situ star formation rate (SFR) is determined by the halo mass accretion rate (MAR), which we call stellar halo accretion rate coevolution (SHARC). We show that the ∼0.3 dex dispersion of the halo MAR matches the observed dispersion of the SFR on the star formation main sequence (MS). In the context of 'bathtub'-type models of galaxy formation, SHARC leads to mass-dependent constraints on the relation between SFR and MAR. Despite its simplicity and the simplified treatment of mass growth from mergers, the SHARC model is likely to be a good approximation for central galaxies with M* = 109-1010.5M☉ that are on the MS, representing most of the star formation in the Universe. SHARC predictions agree with observed SFRs for galaxies on the MS at low redshifts, agree fairly well at z ∼ 4, but exceed observations at z ≳ 4. Assuming that the interstellar gas mass is constant for each galaxy (the 'equilibrium condition' in bathtub models), the SHARC model allows calculation of net mass loading factors for inflowing and outflowing gas.With assumptions about preventive feedback based on simulations, SHARC allows calculation of galaxy metallicity evolution. If galaxy SFRs indeed track halo MARs, especially at low redshifts, that may help explain the success of models linking galaxy properties to haloes (including age-matching) and the similarities between two-halo galaxy conformity and halo mass accretion conformity. [ABSTRACT FROM AUTHOR]

An increasing amount of recent observational evidence shows that the less massive galaxies are, the higher on average their specific star-formation rates (SSFR = , where is the stellar mass). Such a trend, called the ‘SSFR downsizing’ (SSFR–DS) phenomenon, is seen for local and high-redshift (back to ) galaxy samples. We use observational data related only to disc galaxies and explore how the average SSFR changes with z for different masses. For all masses in the range , the SSFR increases with to a power that seems not to depend on , and at all redshifts smaller galaxies always have higher SSFRs; galaxies less massive than are now forming stars at a greater rate than in the past, assuming constant SFRs over a Hubble time to build stellar mass. We show that these features strongly disagree with the Λ Cold Dark Matter (ΛCDM) halo hierarchical mass accretion rates. Further, by means of self-consistent models of disc galaxy evolution inside growing ΛCDM haloes, the effects of disc-feedback-driven outflows and gas re-accretion on galaxy SSFR histories are explored. The parameters of the outflow and re-accretion schemes are tuned to reproduce the present-day relation (where Mh is the halo mass) inferred from the observationally based function of disc galaxies. In the case of outflows only, the SSFR of individual model galaxies increases with z roughly as ( for all masses (somewhat shallower than observations) with a normalization factor that depends on mass as , i.e more massive galaxies have slightly larger SSFRs, contrary to the observed strong SSFR–DS trend. For the re-accretion cases, the dependence on z remains approximately the same as without gas re-infall, but the correlation with mass increases even for the most reasonable values of the model parameters. The comparison of models and observations in the SSFR– plane at (where the data are more reliable) clearly shows the divergent trend in SSFR when the masses are lower (upsizing versus downsizing). We explain why our models show the reported trends, and conclude that the SSFR–DS phenomenon for low-mass galaxies poses a sharp challenge for ΛCDM-based disc galaxy evolution models. [ABSTRACT FROM AUTHOR]