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We present extended point spread function (PSF) models for the Hyper Suprime-Cam Subaru Strategic Program Public Data Release 3 (HSC-SSP PDR3) in all g, r, i, Z , and Y -bands. Due to its 8.2 m primary mirror and long exposure periods, HSC combines deep images with wide-field coverage. Both properties make HSC one of the most suitable observing facilities for low-surface brightness (LSB) studies, which are particularly sensitive to the PSF. By applying a median stacking technique of point-like sources with different brightness, we show how to construct the HSC-SSP PDR3 PSF models to an extent of R ∼ 5.6 arcmin. These models are appropriate for the HSC-PDR3 intermediate-state data which do not have applied the final aggressive background subtraction. The intermediate-state data is especially stored for users interested in large extended objects, where our new PSFs provide them with a crucial tool to characterise LSB properties at large angles. We demonstrate that our HSC PSFs behave reasonably in two scenarios. In the first one, we generate 2D models of a bright star, showing no evidence of residual structures across the five bands. In the second scenario, we recreate the PSF-scattered light on mock images with special consideration of the effect of this additional flux on LSB measurements. Despite the well-behaved nature of the HSC-PDR3 PSFs, there is a non-negligible impact on the faint light present in the mock images. This impact could lead to incorrect LSB measurements if a proper star subtraction is not applied. The PSF models are publicly available to the astronomical community at github.com/luciagarate/HSC_PSFs (DOI: 10.5281/zenodo.11273118). [ABSTRACT FROM AUTHOR]

We present the first look at star formation histories of galaxy components using ProFuse , a new technique to model the 2D distribution of light across multiple wavelengths using simultaneous spectral and spatial fitting of purely imaging data. We present a number of methods to classify galaxies structurally/morphologically, showing the similarities and discrepancies between these schemes. We show the variation in componentwise mass functions that can occur simply due to the use of a different classification method, which is most dramatic in separating bulges and spheroids. Rather than identifying the best-performing scheme, we use the spread of classifications to quantify uncertainty in our results. We study the cosmic star formation history (CSFH), forensically derived using ProFuse with a sample of ∼7000 galaxies from the Galaxy And Mass Assembly survey. Remarkably, the forensic CSFH recovered via both our method (ProFuse) and traditional Spectral Energy Distribution (SED) fitting (ProSpect) are not only exactly consistent with each other over the past 8 Gyr, but also with the in situ CSFH measured using ProSpect. Furthermore, we separate the CSFH by contributions from spheroids, bulges, and discs. While the vast majority (70 per cent) of present-day star formation takes place in the disc population, we show that 50 per cent of the stars that formed at cosmic noon (8–12 Gyr ago) now reside in spheroids, and present-day bulges are composed of stars that were primarily formed in the very early Universe, with half their stars already formed ∼12 Gyr ago. [ABSTRACT FROM AUTHOR]

Traditionally, the far-ultraviolet (FUV) to far-infrared (FIR) and radio spectral energy distributions (SEDs) of galaxies have been considered separately despite the common physical process shaping them. In this work, we explore the utility of simultaneously fitting FUV-radio SEDs using an extended version of the ProSpect SED fitting code considering contributions from both free–free and synchrotron emission. We use a small sample of galaxies from the Deep Extragalactic VIsible Legacy Survey (DEVILS) and the Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel (KINGFISH) where high-quality and robust FUV-radio data are available to provide an ideal sample for testing a radio extension of ProSpect. As the parametrization of the radio extension links the radio continuum to the FIR emission, we explore the benefit of using radio continuum measurements as a constraint on the energy balance between dust attenuation and emission. We find that for situations where mid-IR–FIR photometry is unavailable, including a 1.4 GHz continuum measurement allows for improved accuracy in recovered star formation rates and dust luminosities of galaxies reducing the median uncertainty by 0.1 and 0.2 dex, respectively. We also demonstrate that incorporating 3 and 10 GHz measurements allows for further constraint on the energy balance and therefore the star formation rate and dust luminosity. This demonstrates the advantage of extending FUV–FIR SED fitting techniques to radio frequencies, especially as we move into an era where FIR surveys will remain limited and radio data become abundant (i.e. with the SKA and precursors). [ABSTRACT FROM AUTHOR]

The time-scales on which galaxies move out of the blue cloud to the red sequence (⁠|$\tau ^{}_\mathrm{Q}$|) provide insight into the mechanisms driving quenching. Here, we build upon previous work, where we showcased a method to reconstruct the colour evolution of observed low-redshift galaxies from the Galaxy And Mass Assembly (GAMA) survey based on spectral energy distribution (SED) fitting with ProSpect , together with a statistically driven definition for the blue and red populations. We also use the predicted colour evolution from the shark semi-analytic model, combined with SED fits of our simulated galaxy sample, to study the accuracy of the measured |$\tau ^{}_\mathrm{Q}$| and gain physical insight into the colour evolution of galaxies. In this work, we measure |$\tau ^{}_\mathrm{Q}$| in a consistent approach for both observations and simulations. After accounting for selection bias, we find evidence for an increase in |$\tau ^{}_\mathrm{Q}$| in GAMA as a function of cosmic time (from |$\tau ^{}_\mathrm{Q}$| ∼ 1 Gyr to |$\tau ^{}_\mathrm{Q}$| ∼ 2 Gyr in the lapse of ∼4 Gyr), but not in shark (⁠|$\tau ^{}_\mathrm{Q}$| ≲ 1 Gyr). Our observations and simulations disagree on the effect of stellar mass, with GAMA showing massive galaxies transitioning faster, but is the opposite in shark. We find that environment only impacts galaxies below ∼1010 M⊙ in GAMA, with satellites having shorter |$\tau ^{}_\mathrm{Q}$| than centrals by ∼0.4 Gyr, with shark only in qualitative agreement. Finally, we compare to previous literature, finding consistency with time-scales in the order of couple Gyr, but with several differences that we discuss. [ABSTRACT FROM AUTHOR]

Gas-phase metallicities of galaxies are typically measured through auroral or nebular emission lines, but metallicity also leaves an imprint on the overall spectral energy distribution (SED) of a galaxy and can be estimated through SED fitting. We use the ProSpect SED fitting code with a flexible parametric star formation history and an evolving metallicity history to self-consistently measure metallicities, stellar mass, and other galaxy properties for |$\sim 90\, 000$| galaxies from the Deep Extragalactic VIsible Legacy Survey (DEVILS) and Galaxy and Mass Assembly (GAMA) survey. We use these to trace the evolution of the mass–metallicity relation (MZR) and show that the MZR only evolves in normalization by |$\sim 0.1\,$| dex at stellar mass |$M_\star = 10^{10.5}\, \mathrm{M}_\odot$|⁠. We find no difference in the MZR between galaxies with and without SED evidence of active galactic nuclei emission at low redshifts (⁠|$z$| < 0.3). Our results suggest an anticorrelation between metallicity and star formation activity at fixed stellar mass for galaxies with |$M_\star \gt 10^{10.5}\, \mathrm{M}_\odot$| for |$z$| < 0.3. Using the star formation histories extracted using ProSpect we explore higher order correlations of the MZR with properties of the star formation history including age, width, and shape. We find that at a given stellar mass, galaxies with higher metallicities formed most of their mass over shorter time-scales, and before their peak star formation rate. This work highlights the value of exploring the connection of a galaxy's current gas-phase metallicity to its star formation history in order to understand the physical processes shaping the MZR. [ABSTRACT FROM AUTHOR]

We construct the halo mass function (HMF) from the GAMA (Galaxy And Mass Assembly) galaxy group catalogue over the mass range of 1012.7–1015.5 M⊙, and find good agreement with the expectation from Lambda cold dark matter. In comparison to previous studies, this result extends the mass range over which the HMF has now been measured over by an order of magnitude. We combine the GAMA data release (DR) 4 HMF with similar data from the Sloan Digital Sky Survey (SDSS) DR12 and REFLEX II (ROSAT -ESO Flux Limited X-ray Galaxy Cluster Survey) surveys, and fit a four-parameter Murray–Robotham–Power function, valid at |$\tilde{z} \approx 0.1$|⁠ , yielding a density normalization of log10 (ϕ* Mpc |$^{3})= -3.96^{+0.55}_{-0.82}$|⁠ , a high mass turnover of log10 (M * M |$_{\odot }^{-1})=14.13^{+0.43}_{-0.40}$|⁠ , a low-mass power-law slope of |$\alpha =-1.68^{+0.21}_{-0.24}$|⁠ , and a high-mass softening parameter of |$\beta =0.63^{+0.25}_{-0.11}$|⁠. If we fold in the constraint on ΩM from the Planck 2018 cosmology, we are able to reduce these uncertainties further, but this relies on the assumption that the power-law trend can be extrapolated from 1012.7 M⊙ to zero mass. Throughout, we highlight the effort needed to improve on our HMF measurement: improved halo mass estimates that do not rely on calibration to simulations; reduced halo mass uncertainties needed to mitigate the strong Eddington bias that arises from the steepness of the HMF low-mass slope; and deeper wider area spectroscopic surveys. To our halo mass limit of 1012.7 M⊙, we are directly resolving ('seeing') 41 ± 5 per cent of the total mass density, i.e. ΩM,>12.7 = 0.128 ± 0.016, opening the door for the direct construction of three-dimensional dark matter mass maps at Mpc resolution. [ABSTRACT FROM AUTHOR]

We present catalogues of stellar masses, star formation rates (SFRs), and ancillary stellar population parameters for galaxies spanning 0 < z < 9 from the Deep Extragalactic VIsible Legacy Survey (DEVILS). DEVILS is a deep spectroscopic redshift survey with very high completeness, covering several premier deep fields including COSMOS (D10). Our stellar mass and SFR estimates are self-consistently derived using the spectral energy distribution (SED) modelling code ProSpect , using well-motivated parametrizations for dust attenuation, star formation histories, and metallicity evolution. We show how these improvements, and especially our physically motivated assumptions about metallicity evolution, have an appreciable systematic effect on the inferred stellar masses, at the level of ∼0.2 dex. To illustrate the scientific value of these data, we map the evolving galaxy stellar mass function (SMF) and the SFR– M ⋆ relation for 0 < z < 4.25. In agreement with past studies, we find that most of the evolution in the SMF is driven by the characteristic density parameter, with little evolution in the characteristic mass and low-mass slopes. Where the SFR– M ⋆ relation is indistinguishable from a power law at z > 2.6, we see evidence of a bend in the relation at low redshifts (z < 0.45). This suggests evolution in both the normalization and shape of the SFR– M ⋆ relation since cosmic noon. It is significant that we only clearly see this bend when combining our new DEVILS measurements with consistently derived values for lower redshift galaxies from the Galaxy And Mass Assembly (GAMA) survey: this shows the power of having consistent treatment for galaxies at all redshifts. [ABSTRACT FROM AUTHOR]

We analyse the metallicity histories of ∼4500 galaxies from the GAMA survey at z < 0.06 modelled by the SED-fitting code ProSpect using an evolving metallicity implementation. These metallicity histories, in combination with the associated star formation histories, allow us to analyse the inferred gas-phase mass–metallicity relation. Furthermore, we extract the mass–metallicity relation at a sequence of epochs in cosmic history, to track the evolving mass–metallicity relation with time. Through comparison with observations of gas-phase metallicity over a large range of redshifts, we show that, remarkably, our forensic SED analysis has produced an evolving mass–metallicity relationship that is consistent with observations at all epochs. We additionally analyse the three-dimensional mass–metallicity–SFR space, showing that galaxies occupy a clearly defined plane. This plane is shown to be subtly evolving, displaying an increased tilt with time caused by general enrichment, and also the slowing down of star formation with cosmic time. This evolution is most apparent at lookback times greater than 7 Gyr. The trends in metallicity recovered in this work highlight that the evolving metallicity implementation used within the SED-fitting code ProSpect produces reasonable metallicity results over the history of a galaxy. This is expected to provide a significant improvement to the accuracy of the SED-fitting outputs. [ABSTRACT FROM AUTHOR]

We apply the spectral energy distribution (SED) fitting code ProSpect to multiwavelength imaging for ∼7000 galaxies from the GAMA survey at z < 0.06, in order to extract their star formation histories. We combine a parametric description of the star formation history with a closed-box evolution of metallicity where the present-day gas-phase metallicity of the galaxy is a free parameter. We show with this approach that we are able to recover the observationally determined cosmic star formation history (CSFH), an indication that stars are being formed in the correct epoch of the Universe, on average, for the manner in which we are conducting SED fitting. We also show the contribution to the CSFH of galaxies of different present-day visual morphologies and stellar masses. Our analysis suggests that half of the mass in present-day elliptical galaxies was in place 11 Gyr ago. In other morphological types, the stellar mass formed later, up to 6 Gyr ago for present-day irregular galaxies. Similarly, the most massive galaxies in our sample were shown to have formed half their stellar mass by 11 Gyr ago, whereas the least massive galaxies reached this stage as late as 4 Gyr ago (the well-known effect of 'galaxy downsizing'). Finally, our metallicity approach allows us to follow the average evolution in gas-phase metallicity for populations of galaxies and extract the evolution of the cosmic metal mass density in stars and in gas, producing results in broad agreement with independent, higher redshift observations of metal densities in the Universe. [ABSTRACT FROM AUTHOR]

We combine the shark semi-analytic model of galaxy formation with the prospect software tool for spectral energy distribution (SED) generation to study the multiwavelength emission of galaxies from the far-ultraviolet (FUV) to the far-infrared (FIR) at 0 ≤ z ≤ 10. We produce a physical model for the attenuation of galaxies across cosmic time by combining a local Universe empirical relation to compute the dust mass of galaxies from their gas metallicity and mass, attenuation curves derived from radiative transfer calculations of galaxies in the eagle hydrodynamic simulation suite, and the properties of shark galaxies. We are able to produce a wide range of galaxies, from the z  = 8 star-forming galaxies with almost no extinction, z  = 2 submillimetre galaxies, down to the normal star-forming and red-sequence galaxies at z  = 0. Quantitatively, we find that shark reproduces the observed (i) z  = 0 FUV-to-FIR, (ii) 0 ≤ z ≤ 3 rest-frame K -band, and (iii) 0 ≤ z ≤ 10 rest-frame FUV luminosity functions, (iv) z ≤ 8 UV slopes, (v) the FUV-to-FIR number counts (including the widely disputed 850  μ m), (vi) redshift distribution of bright |$850\, \mu$| m galaxies, and (vii) the integrated cosmic SED from z  = 0 to 1 to an unprecedented level. This is achieved without the need to invoke changes in the stellar initial mass function, dust-to-metal mass ratio, or metal enrichment time-scales. Our model predicts star formation in galaxy discs to dominate in the FUV-to-optical, while bulges dominate at the NIR at all redshifts. The FIR sees a strong evolution in which discs dominate at z ≤ 1 and starbursts (triggered by both galaxy mergers and disc instabilities, in an even mix) dominate at higher redshifts, even out to z  = 10. [ABSTRACT FROM AUTHOR]

We present a revised measurement of the extragalactic background light (EBL) at radio frequencies based on a near complete compendium of radio source counts. We present the radio-EBL at 150 MHz, 325 MHz, 610 MHz, 1.4 GHz, 3 GHz, 5 GHz, and 8.4 GHz. In all cases the contribution to the radio-EBL, per decade of flux, exhibits a two-humped distribution well matched to the active galactic nucleus (AGN) and star-forming galaxy (SFG) populations, and with each population contributing roughly equal energy. Only at 3 GHz are the source count contributions to the EBL fully convergent, and hence we report empirical lower limits to the radio-EBL in the remaining bands. Adopting predictions from the SHARK semi-analytic model for the form of the SFG population, we can fit the fainter source counts providing measurements of the total contribution to the radio-EBL for the SFG and the AGN populations separately. This constitutes an empirically constrained model-dependent measurement for the SFG contribution, but a fully empirical measurement of the AGN contribution. Using the ProSpect spectral energy distribution code we can model the ultraviolet-optical-infrared-mm-radio SFG EBL at all frequencies from the cosmic star-formation history and the adoption of a Chabrier initial mass function. However, significant discrepancy remains (5 ×) between our source-count estimates of the radio-EBL and the direct measurements reported from the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission-2 (ARCADE-2) experiment. We can rule out a significant missing discrete source radio population and suggest that the cause of the high ARCADE-2 radio-EBL values may need to be sought either in the foreground subtraction or as a yet unknown diffuse component in the radio sky. [ABSTRACT FROM AUTHOR]

ABSTRACT We have generated complementary halo mass estimates for all the groups in the Galaxy And Mass Assembly Galaxy Group Catalogue (GAMA G3Cv1) using a modified caustic mass estimation algorithm, originally developed by Diaferio & Geller. We calibrate the algorithm by applying it on a series of nine GAMA mock galaxy light cones and investigate the effects of using different definitions for group centre and size. We select the set of parameters that provide median-unbiased mass estimates when tested on mocks, and generate mass estimates for the real group catalogue. We find that on average, the caustic mass estimates agree with dynamical mass estimates within a factor of 2 in 90.8 ± 6.1 per cent groups and compare equally well to velocity dispersion based mass estimates for both high- and low-multiplicity groups over the full range of masses probed by the G3Cv1. [ABSTRACT FROM AUTHOR]

We determine an expression for the cosmic variance of any ‘normal’ galaxy survey based on examination of mag galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) data cube. We find that cosmic variance will depend on a number of factors principally: total survey volume, survey aspect ratio and whether the area surveyed is contiguous or comprising independent sightlines. As a rule of thumb cosmic variance falls below 10 per cent once a volume of Mpc3 is surveyed for a single contiguous region with a 1:1 aspect ratio. Cosmic variance will be lower for higher aspect ratios and/or non-contiguous surveys. Extrapolating outside our test region we infer that cosmic variance in the entire SDSS DR7 main survey region is ∼7 per cent to . The equation obtained from the SDSS DR7 region can be generalized to estimate the cosmic variance for any density measurement determined from normal galaxies (e.g. luminosity densities, stellar mass densities and cosmic star formation rates) within the volume range Mpc3. We apply our equation to show that two sightlines are required to ensure that cosmic variance is <10 per cent in any ASKAP galaxy survey (divided into intervals, i.e. ∼1 Gyr intervals for ). Likewise 10 MeerKAT sightlines will be required to meet the same conditions. GAMA, VVDS and zCOSMOS all suffer less than 10 per cent cosmic variance (∼3–8 per cent) in intervals of 0.1, 0.25 and 0.5, respectively. Finally we show that cosmic variance is potentially at the 50–70 per cent level, or greater, in the Hubble Space Telescope ( HST) Ultra Deep Field depending on assumptions as to the evolution of clustering. 100 or 10 independent sightlines will be required to reduce cosmic variance to a manageable level (<10 per cent) for HST ACS or HST WFC3 surveys, respectively (in intervals). Cosmic variance is therefore a significant factor in the HST studies currently underway. [ABSTRACT FROM AUTHOR]

We derive single Sérsic fits and bulge-disc decompositions for 13 096 galaxies at redshifts z < 0.08 in the GAMA II equatorial survey regions in the Kilo-Degree Survey (KiDS) g, r , and i bands. The surface brightness fitting is performed using the Bayesian two-dimensional profile fitting code ProFit. We fit three models to each galaxy in each band independently with a fully automated Markov chain Monte Carlo analysis: a single Sérsic model, a Sérsic plus exponential and a point source plus exponential. After fitting the galaxies, we perform model selection and flag galaxies for which none of our models are appropriate (mainly mergers/Irregular galaxies). The fit quality is assessed by visual inspections, comparison to previous works, comparison of independent fits of galaxies in the overlap regions between KiDS tiles and bespoke simulations. The latter two are also used for a detailed investigation of systematic error sources. We find that our fit results are robust across various galaxy types and image qualities with minimal biases. Errors given by the MCMC underestimate the true errors typically by factors 2–3. Automated model selection criteria are accurate to |$\gt 90{{\ \rm per\ cent}}$| as calibrated by visual inspection of a subsample of galaxies. We also present g − r component colours and the corresponding colour–magnitude diagram, consistent with previous works despite our increased fit flexibility. Such reliable structural parameters for the components of a diverse sample of galaxies across multiple bands will be integral to various studies of galaxy properties and evolution. All results are integrated into the GAMA database. [ABSTRACT FROM AUTHOR]

We introduce version 2.0 of the shark semi-analytic model of galaxy formation after many improvements to the physics included. The most significant being (i) a model describing the exchange of angular momentum (AM) between the interstellar medium and stars; (ii) a new active galactic nuclei feedback model which has two modes, a wind and a jet mode, with the jet mode tied to the jet energy production; (iii) a model tracking the development of black hole (BH) spins; (iv) more sophisticated modelling of environmental effects on satellite galaxies; and (v) automatic parameter exploration using Particle Swarm Optimization. We focus on two timely research topics: the structural properties of galaxies and the quenching of massive galaxies. For the former, shark v2.0 is capable of producing a more realistic stellar size–mass relation with a plateau marking the transition from disc- to bulge-dominated galaxies, and scaling relations between specific AM and mass that agree well with observations. For the quenching of massive galaxies, shark v2.0 produces massive galaxies that are more quenched than the previous version, reproducing well the observed relations between star formation rate (SFR) and stellar mass, and specific SFR and BH mass at z  = 0. shark v2.0 produces a number density of massive-quiescent galaxies >1 dex higher than the previous version, in good agreement with JWST observations at z ≤ 5; predicts a stellar mass function of passive galaxies in reasonably good agreement with observations at 0.5 < z < 5; and environmental quenching to already be effective at z  = 5. [ABSTRACT FROM AUTHOR]

The tight relationship between infrared luminosity (L TIR) and 1.4 GHz radio continuum luminosity (⁠|$L_\mathrm{1.4\, GHz}$|⁠) has proven useful for understanding star formation free from dust obscuration. Infrared emission in star-forming galaxies typically arises from recently formed, dust-enshrouded stars, whereas radio synchrotron emission is expected from subsequent supernovae. By leveraging the wealth of ancillary far-ultraviolet – far-infrared photometry from the Deep Extragalactic VIsible Legacy Survey and Galaxy and Mass Assembly surveys, combined with 1.4 GHz observations from the Meer Karoo Array Telescope International GHz Tiered Extragalactic Exploration survey and Deep Investigation of Neutral Gas Origin projects, we investigate the impact of time-scale differences between far-ultraviolet – far-infrared and radio-derived star formation rate (SFR) tracers. We examine how the spectral energy distribution (SED)-derived star formation histories (SFHs) of galaxies can be used to explain discrepancies in these SFR tracers, which are sensitive to different time-scales. Galaxies exhibiting an increasing SFH have systematically higher L TIR and SED-derived SFRs than predicted from their 1.4 GHz radio luminosity. This indicates that insufficient time has passed for subsequent supernovae-driven radio emission to accumulate. We show that backtracking the SFR(t) of galaxies along their SED-derived SFHs to a time several hundred megayears prior to their observed epoch will both linearize the SFR– |$L_\mathrm{1.4\, GHz}$| relation and reduce the overall scatter. The minimum scatter in the SFR(t)– |$L_\mathrm{1.4\, GHz}$| is reached at 200 – 300 Myr prior, consistent with theoretical predictions for the time-scales required to disperse the cosmic ray electrons responsible for the synchrotron emission. [ABSTRACT FROM AUTHOR]

In Galaxy And Mass Assembly Data Release 4 (GAMA DR4), we make available our full spectroscopic redshift sample. This includes 248 682 galaxy spectra, and, in combination with earlier surveys, results in 330 542 redshifts across five sky regions covering ∼250 deg2. The redshift density, is the highest available over such a sustained area, has exceptionally high completeness (95 per cent to r KiDS = 19.65 mag), and is well-suited for the study of galaxy mergers, galaxy groups, and the low redshift (z  < 0.25) galaxy population. DR4 includes 32 value-added tables or Data Management Units (DMUs) that provide a number of measured and derived data products including GALEX , ESO KiDS, ESO VIKING, WISE , and Herschel Space Observatory imaging. Within this release, we provide visual morphologies for 15 330 galaxies to z  < 0.08, photometric redshift estimates for all 18 million objects to r KiDS ∼ 25 mag, and stellar velocity dispersions for 111 830 galaxies. We conclude by deriving the total galaxy stellar mass function (GSMF) and its sub-division by morphological class (elliptical, compact-bulge and disc, diffuse-bulge and disc, and disc only). This extends our previous measurement of the total GSMF down to 106.75 M |$_{\odot } \, h_{70}^{-2}$| and we find a total stellar mass density of ρ * = (2.97 ± 0.04) × 108 M |$_{\odot } \, h_{70}$|  Mpc−3 or |$\Omega _*=(2.17 \pm 0.03) \times 10^{-3} \, h_{70}^{-1}$|⁠. We conclude that at z  < 0.1, the Universe has converted 4.9 ± 0.1 per cent of the baryonic mass implied by big bang Nucleosynthesis into stars that are gravitationally bound within the galaxy population. [ABSTRACT FROM AUTHOR]

We perform a structural decomposition of galaxies identified in three cosmological hydrodynamical simulations by applying Gaussian mixture models (GMMs) to the kinematics of their stellar particles. We study the resulting disc, bulge, and intra-halo light (IHL) components of galaxies whose host dark matter haloes have virial masses in the range M 200 = 1011– |$10^{15}\, {\rm M_\odot }$|⁠. Our decomposition technique isolates galactic discs whose mass fractions, f disc, correlate strongly with common alternative morphology indicators; for example, f disc is approximately equal to κco, the fraction of stellar kinetic energy in corotation. The primary aim of our study, however, is to characterize the IHL of galaxies in a consistent manner and over a broad mass range, and to analyse its properties from the scale of galactic stellar haloes up to the intra-cluster light. Our results imply that the IHL fraction, f IHL, has appreciable scatter and is strongly correlated with galaxy morphology: at fixed stellar mass, the IHL of disc galaxies is typically older and less massive than that of spheroids. Above |$M_{200}\approx 10^{13}\, {\rm M_\odot }$|⁠ , we find, on average, f IHL ≈ 0.37, albeit with considerable scatter. The transition radius beyond which the IHL dominates the stellar mass of a galaxy is roughly |$30\, {\rm kpc}$| for disc galaxies, but depends strongly on halo mass for spheroids. However, we find that no alternative IHL definitions – whether based on the ex situ stellar mass, or the stellar mass outside a spherical aperture – reproduce our dynamically defined IHL masses. [ABSTRACT FROM AUTHOR]

We thoroughly explore the properties of (sub)-millimetre (mm) selected galaxies (SMGs) in the shark semi-analytic model of galaxy formation. Compared to observations, the predicted number counts at wavelengths (λ) 0.6–2 mm and redshift distributions at 0.1–2 mm, agree well. At the bright end (≳1 mJy), shark galaxies are a mix of mergers and disc instabilities. These galaxies display a stacked far-ultraviolet (FUV)-to-far-infrared (FIR) spectrum that agrees well with observations. We predict that current optical/NIR surveys are deep enough to detect bright (>1 mJy) λ = 0.85–2 mm-selected galaxies at z ≲ 5, but too shallow to detect counterparts at higher redshift. A James Webb Space Telescope 10 000s survey should detect all counterparts for galaxies with S 0.85mm ≳ 0.01 mJy. We predict SMG's disks contribute significantly (negligibly) to the rest-frame UV (IR). We investigate the 0 ≤ z ≤ 6 evolution of the intrinsic properties of >1 mJy λ = 0.85–2 mm-selected galaxies finding their: (i) stellar masses are |$\gt 10^{10.2}\rm \, M_{\odot }$|⁠ , with the 2 mm ones tracing the most massive galaxies (⁠|$\gt 10^{11}\rm \, M_{\odot }$|⁠); (ii) specific star formation rates (SFR) are mildly (≈3–10 times) above the main sequence (MS); (iii) host halo masses are |$\gtrsim 10^{12.3}\, \rm M_{\odot }$|⁠ , with 2 mm galaxies tracing the most massive haloes (protoclusters); (iv) SMGs have lower dust masses (⁠|$\approx 10^{8}\, \rm M_{\odot }$|⁠), higher dust temperatures (≈40–45 K) and higher rest-frame V -band attenuation (>1.5) than MS galaxies; (v) sizes decrease with redshift, from 4 kpc at z  = 1 to ≲1 kpc at z  = 4; and (vi) the carbon monoxide line spectra of S 0.85mm ≳ 1 mJy sources peak at 4 → 3. Finally, we study the contribution of SMGs to the molecular gas and cosmic SFR density at 0 ≤ z ≤ 10, finding that >1 mJy sources make a negligible contribution at z ≳ 3 and 5, respectively, suggesting current observations have unveiled the majority of the SF at 0 ≤ z ≤ 10. [ABSTRACT FROM AUTHOR]

The Galaxy And Mass Assembly Survey (GAMA) covers five fields with highly complete spectroscopic coverage (>95 per cent) to intermediate depths (r < 19.8 or i < 19.0 mag), and collectively spans 250 deg2 of equatorial or southern sky. Four of the GAMA fields (G09, G12, G15, and G23) reside in the European Southern Observatory (ESO) VST KiDS and ESO VISTA VIKING survey footprints, which combined with our GALEX, WISE , and Herschel data provide deep uniform imaging in the |$FUV/NUV/u/g/r/i/Z/Y/J/H/K_s/W1/W2/W3/W4/P100/P160/S250/S350/S500$| bands. Following the release of KiDS DR4, we describe the process by which we ingest the KiDS data into GAMA (replacing the SDSS data previously used for G09, G12, and G15), and redefine our core optical and near-infrared (NIR) catalogues to provide a complete and homogeneous data set. The source extraction and analysis is based on the new ProFound image analysis package, providing matched-segment photometry across all bands. The data are classified into stars, galaxies, artefacts, and ambiguous objects, and objects are linked to the GAMA spectroscopic target catalogue. Additionally, a new technique is employed utilizing ProFound to extract photometry in the unresolved MIR–FIR regime. The catalogues including the full FUV–FIR photometry are described and will be fully available as part of GAMA DR4. They are intended for both standalone science, selection for targeted follow-up with 4MOST, as well as an accompaniment to the upcoming and ongoing radio arrays now studying the GAMA 23h field. [ABSTRACT FROM AUTHOR]

We present a simple model for galaxy attenuation by fitting skirt radiative transfer calculations for ∼10 000 eagle galaxies at redshifts z  = 2 − 0. Our model adapts the two-component screen model of Charlot & Fall, parametrizing the optical depth and slope of the interstellar medium screen using the average dust surface density, Σdust. We recover relatively tight relations between these parameters for the eagle sample, but also provide the scatter in these parameters owing to the morphological variation and orientation of galaxies. We also find that these relations are nearly independent of redshift in the eagle model. By pairing our model with an empirical prescription for birth clouds below the resolution scale of the simulation, we reproduce the observed relation between attenuation slope and optical depth for the first time in a cosmological simulation. We demonstrate that this result is remarkably independent of the attenuation properties assumed for the birth cloud screen, merely requiring a boosted attenuation for infant stars. We present this model with a view to interpreting observations, as well as processing semi-analytic models and other hydrodynamic simulations. [ABSTRACT FROM AUTHOR]

Hierarchical models of structure formation predict that dark matter halo assembly histories are characterized by episodic mergers and interactions with other haloes. An accurate description of this process will provide insights into the dynamical evolution of haloes and the galaxies that reside in them. Using large cosmological N -body simulations, we characterize halo orbits to study the interactions between substructure haloes and their hosts, and how different evolutionary histories map to different classes of orbits. We use two new software tools – WhereWolf , which uses halo group catalogues and merger trees to ensure that haloes are tracked accurately in dense environments, and OrbWeaver , which quantifies each halo's orbital parameters. We demonstrate how WhereWolf improves the accuracy of halo merger trees, and we use OrbWeaver to quantify orbits of haloes. We assess how well analytical prescriptions for the merger time-scale from the literature compare to measured merger time-scales from our simulations and find that existing prescriptions perform well, provided the ratio of substructure-to-host mass is not too small. In the limit of small substructure-to-host mass ratio, we find that the prescriptions can overestimate the merger time-scales substantially, such that haloes are predicted to survive well beyond the end of the simulation. This work highlights the need for a revised analytical prescription for the merger time-scale that more accurately accounts for processes such as catastrophic tidal disruption. [ABSTRACT FROM AUTHOR]

The Galaxy And Mass Assembly (GAMA) survey has morphologically identified a class of 'Little Blue Spheroid' (LBS) galaxies whose relationship to other classes of galaxies we now examine in detail. Considering a sample of 868 LBSs, we find that such galaxies display similar but not identical colours, specific star formation rates, stellar population ages, mass-to-light ratios, and metallicities to Sd-Irr galaxies. We also find that LBSs typically occupy environments of even lower density than those of Sd-Irr galaxies, where ∼65 per cent of LBS galaxies live in isolation. Using deep, high-resolution imaging from VST KiDS and the new Bayesian, 2D galaxy profile modelling code profit , we further examine the detailed structure of LBSs and find that their Sérsic indices, sizes, and axial ratios are compatible with those of low-mass elliptical galaxies. We then examine SAMI Galaxy survey integral field emission line kinematics for a subset of 62 LBSs and find that the majority (42) of these galaxies display ordered rotation with the remainder displaying disturbed/non-ordered dynamics. Finally, we consider potential evolutionary scenarios for a population with this unusual combination of properties, concluding that LBSs are likely formed by a mixture of merger and accretion processes still recently active in low-redshift dwarf populations. We also infer that if LBS-like galaxies were subjected to quenching in a rich environment, they would plausibly resemble cluster dwarf ellipticals. [ABSTRACT FROM AUTHOR]

We use the Galaxy and Mass Assembly (GAMA) and the Deep Extragalactic Visible Legacy Survey (DEVILS) observational data sets to calculate the cosmic star formation rate (SFR) and active galactic nuclei (AGN) bolometric luminosity history (CSFH/CAGNH) over the last 12.5 billion years. SFRs and AGN bolometric luminosities were derived using the spectral energy distribution fitting code ProSpect , which includes an AGN prescription to self-consistently model the contribution from both AGN and stellar emission to the observed rest-frame ultra-violet to far-infrared photometry. We find that both the CSFH and CAGNH evolve similarly, rising in the early Universe up to a peak at look-back time ≈10 Gyr (z ≈ 2), before declining towards the present day. The key result of this work is that we find the ratio of CAGNH to CSFH has been flat (⁠|$\approx 10^{42.5}\, \mathrm{erg \, s^{-1}\, {\rm M}_{\odot }^{-1}\, yr}$|⁠) for 11 Gyr up to the present day, indicating that star formation and AGN activity have been coeval over this time period. We find that the stellar masses of the galaxies that contribute most to the CSFH and CAGNH are similar, implying a common cause, which is likely gas inflow. The depletion of the gas supply suppresses cosmic star formation and AGN activity equivalently to ensure that they have experienced similar declines over the last 10 Gyr. These results are an important milestone for reconciling the role of star formation and AGN activity in the life cycle of galaxies. [ABSTRACT FROM AUTHOR]

We determine the atomic hydrogen (H  i) to halo mass relation (HIHM) using Arecibo Legacy Fast ALFA survey H  i data at the location of optically selected groups from the Galaxy And Mass Assembly (GAMA) survey. We make direct H  i detections for 37 GAMA groups. Using H  i group spectral stacking of 345 groups, we study the group H  i content as a function of halo mass across a halo mass range of 1011–1014.7 M⊙. We also correct our results for Eddington bias. We find that the group H  i mass generally rises as a function of halo mass from 1.3% of the halo mass at |$10^{11.6} \, \text{M}_\odot$| to 0.4% at |$10^{13.7} \, \text{M}_\odot$| with some indication of flattening towards the high-mass end. Despite the differences in optical survey limits, group catalogues, and halo mass estimation methods, our results are consistent with previous group H  i -stacking studies. Our results are also consistent with mock observations from shark and IllustrisTNG. [ABSTRACT FROM AUTHOR]

We present a new, open source, free, semi-analytic model (SAM) of galaxy formation, Shark, designed to be highly flexible and modular, allowing easy exploration of different physical processes and ways of modelling them. We introduce the philosophy behind Shark and provide an overview of the physical processes included in the model. Shark is written in C++11 and has been parallelized with OpenMP. In the released version (v1.1), we implement several different models for gas cooling, active galactic nuclei, stellar and photo-ionization feedback, and star formation (SF). We demonstrate the basic performance of Shark using the Planck Collaboration et al. (2016) cosmology SURFS simulations, by comparing against a large set of observations, including: the stellar mass function (SMF) and stellar–halo mass relation at |$z$| = 0–4; the cosmic evolution of the star formation rate density (SFRD), stellar mass, atomic and molecular hydrogen; local gas scaling relations; and structural galaxy properties, finding excellent agreement. Significant improvements over previous SAMs are seen in the mass–size relation for discs/bulges, the gas–stellar mass and stellar mass–metallicity relations. To illustrate the power of Shark in exploring the systematic effects of the galaxy formation modelling, we quantify how the scatter of the SF main sequence and the gas scaling relations changes with the adopted SF law, and the effect of the starbursts H2depletion time-scale on the SFRD and |$\Omega _{\rm H_2}$|⁠. We compare Shark with other SAMs and the hydrodynamical simulation EAGLE, and find that SAMs have a much higher halo baryon fractions due to large amounts of intra-halo gas, which in the case of EAGLE is in the intergalactic medium. [ABSTRACT FROM AUTHOR]

The spherical Jeans equation is a widely used tool for dynamical study of gravitating systems in astronomy. Here we test its efficacy in robustly weighing the mass of Milky Way analogues, given they need not be in equilibrium or even spherical. Utilizing Milky Way stellar halos simulated in accordance with ΛCDM cosmology by Bullock and Johnston (2005) and analysing them under the Jeans formalism, we recover the underlying mass distribution of the parent galaxy, within distance r/kpc ∈ [10,100], with a bias of ~12% and a dispersion of ~14%. Additionally, the mass profiles of triaxial dark matter halos taken from the SURFS simulation, within scaled radius 0.2

The first and second moments of stellar velocities encode important information about the formation history of the Galactic halo. However, due to the lack of tangential motion and inaccurate distances of the halo stars, the velocity moments in the Galactic halo have largely remained 'known unknowns'. Fortunately, our off-centric position within the Galaxy allows us to estimate these moments in the galactocentric frame using the observed radial velocities of the stars alone.We use these velocities coupled with the hierarchical Bayesian scheme, which allows easy marginalization over the missing data (the proper motion and uncertainty-free distance and line-of-sight velocity), to measure the velocity dispersions, orbital anisotropy (β) and streaming motion (vrot) of the halo main-sequence turn-off (MSTO) and K-giant (KG) stars in the inner stellar halo (r = 15 kpc). We study the metallicity bias in kinematics of the halo stars and observe that the comparatively metal-rich ([Fe/H] > −1.4) and the metal-poor ([Fe/H]≤−1.4) MSTO samples show a clear systematic difference in vrot ∼ 20−40 km s−1, depending on how restrictive the spatial cuts to cull the disc contamination are. The bias is also detected in KG samples but with less certainty. Both MSTO and KG populations suggest that the inner stellar halo of the Galaxy is radially biased i.e. σr > σθ or σφ and β > 0.5. The apparent metallicity contrariety in the rotation velocity among the halo sub-populations supports the co-existence of multiple populations in the galactic halo that may have formed through distinct formation scenarios, i.e. in situ versus accretion. [ABSTRACT FROM AUTHOR]

We present early science results from Deep Investigation of Neutral Gas Origins (DINGO), an |$\rm H$| i survey using the Australian Square Kilometre Array Pathfinder (ASKAP). Using ASKAP subarrays available during its commissioning phase, DINGO early science data were taken over ∼60 deg2 of the Galaxy And Mass Assembly (GAMA) 23 h region with 35.5 h integration time. We make direct detections of six known and one new sources at z < 0.01. Using |$\rm H$|   i spectral stacking, we investigate the |$\rm H$|   i gas content of galaxies at 0.04 < z < 0.09 for different galaxy colours. The results show that galaxy morphology based on optical colour is strongly linked to |$\rm H$|   i gas properties. To examine environmental impacts on the |$\rm H$| i gas content of galaxies, three subsamples are made based on the GAMA group catalogue. The average |$\rm H$| i mass of group central galaxies is larger than those of satellite and isolated galaxies, but with a lower |$\rm H$| i gas fraction. We derive a variety of |$\rm H$| i scaling relations for physical properties of our sample, including stellar mass, stellar mass surface density, NUV − r colour, specific star formation rate, and halo mass. We find that the derived |$\rm H$| i scaling relations are comparable to other published results, with consistent trends also observed to ∼0.5 dex lower limits in stellar mass and stellar surface density. The cosmic |$\rm H$| i densities derived from our data are consistent with other published values at similar redshifts. DINGO early science highlights the power of |$\rm H$| i spectral stacking techniques with ASKAP. [ABSTRACT FROM AUTHOR]

We present a pilot study to assess the potential of Hyper Suprime-Cam Public Data Release 2 (HSC-PDR2) images for the analysis of extended faint structures within groups of galaxies. We examine the intragroup light (IGL) of the group 400138 (M dyn = 1.3 ± 0.5 × 1013 M⊙, z ∼ 0.2) from the Galaxy And Mass Assembly (GAMA) survey using Hyper Suprime-Cam Subaru Strategic Program Public Data Release 2 (HSC-SSP PDR2) images in g, r , and i bands. We present the most extended IGL measurement to date, reaching down to |$\mu _{g}^{\rm {lim}}=30.76$|  mag arcsec−2 (3σ; 10 × 10 arcsec2) at a semimajor axis of 275 kpc. The IGL shows mean colour values of g − i  = 0.92, g − r  = 0.60, and r − i  = 0.32 (±0.01). The IGL stellar populations are younger (2–2.5 Gyr) and less metal rich ([Fe/H] ∼ −0.4) than those of the host group galaxies. We find a range of IGL fractions as a function of total group luminosity of |${\sim} 2\!-\!36 {{\ \rm per\ cent}}$| depending on the definition of IGL, with larger fractions the bluer the observation wavelength. The early-type to late-type galaxy ratio suggests that 400138 is a more evolved group, dominated by early-type galaxies, and the IGL fraction agrees with that of other similarly evolved groups. These results are consistent with tidal stripping of the outer parts of Milky Way-like galaxies as the main driver of the IGL build-up. This is supported by the detection of substructure in the IGL towards the galaxy member 1660615 suggesting a recent interaction (<1 Gyr ago) of that galaxy with the core of the group. [ABSTRACT FROM AUTHOR]

We present the results of a search for associated 21 cm H  i absorption at redshift 0.42 < z < 1.00 in radio-loud galaxies from three Galaxy And Mass Assembly (GAMA) survey fields. These observations were carried out as part of a pilot survey for the Australian SKA Pathfinder (ASKAP) First Large Absorption Survey in H  i (FLASH). From a sample of 326 radio sources with 855.5 MHz peak flux density above 10 mJy, we detected two associated H  i absorption systems, in SDSS J090331+010847 at z  = 0.522 and SDSS J113622+004852 at z  = 0.563. Both galaxies are massive (stellar mass |$\gt 10^{11}\, \mathrm{M}_\odot$|⁠) and have optical spectra characteristic of luminous red galaxies, though spectral energy distribution fitting implies that SDSS J113622+004852 contains a dust-obscured starburst with star formation rate ∼69 M⊙ yr−1. The H  i absorption lines have a high optical depth, with τpk of 1.77 ± 0.16 for SDSS J090331+010847 (the highest value for any z > 0.1 associated system found to date) and 0.14 ± 0.01 for SDSS J113622+004852. In the redshift range probed by our ASKAP observations, the detection rate for associated H  i absorption lines (with τpk > 0.1 and at least 3σ significance) is |$2.9_{-2.6}^{+9.7}$|  per cent. Although the current sample is small, this rate is consistent with a trend seen in other studies for a lower detection rate of associated 21 cm H  i absorption systems at higher redshift. We also searched for OH absorption lines at 0.67 < z < 1.34, but no detection was made in the 145 radio sources searched. [ABSTRACT FROM AUTHOR]

We present a complete structural analysis of the ellipticals (E), diffuse bulges (dB), compact bulges (cB), and discs (D) within a redshift range 0 < z < 1, and stellar mass log10(M*/M⊙) ≥ 9.5 volume-limited sample drawn from the combined DEVILS and HST -COSMOS region. We use the profit code to profile over ∼35 000 galaxies for which visual classification into single or double component was pre-defined in Paper-I. Over this redshift range, we see a growth in the total stellar mass density (SMD) of a factor of 1.5. At all epochs we find that the dominant structure, contributing to the total SMD, is the disc, and holds a fairly constant share of |$\sim 60{{\ \rm per\ cent}}$| of the total SMD from z  = 0.8 to z  = 0.2, dropping to |$\sim 30{{\ \rm per\ cent}}$| at z  = 0.0 (representing |$\sim 33{{\ \rm per\ cent}}$| decline in the total disc SMD). Other classes (E, dB, and cB) show steady growth in their numbers and integrated stellar mass densities. By number, the most dramatic change across the full mass range is in the growth of diffuse bulges. In terms of total SMD, the biggest gain is an increase in massive elliptical systems, rising from 20 per cent at z  = 0.8 to equal that of discs at z  = 0.0 (30 per cent) representing an absolute mass growth of a factor of 2.5. Overall, we see a clear picture of the emergence and growth of all three classes of spheroids over the past 8 Gyr, and infer that in the later half of the Universe's timeline spheroid-forming processes and pathways (secular evolution, mass-accretion, and mergers) appear to dominate mass transformation over quiescent disc growth. [ABSTRACT FROM AUTHOR]

We use data from the Galaxy And Mass Assembly (GAMA) survey in the redshift range 0.01 < z < 0.1 (8399 galaxies in g to Ks bands) to derive the stellar mass–half-light radius relations for various divisions of ‘early’- and ‘late’-type samples. We find that the choice of division between early and late (i.e. colour, shape, morphology) is not particularly critical; however, the adopted mass limits and sample selections (i.e. the careful rejection of outliers and use of robust fitting methods) are important. In particular, we note that for samples extending to low stellar mass limits (${<}10^{10}\mathcal {M_{\odot }}$) the Sérsic index bimodality, evident for high-mass systems, becomes less distinct and no-longer acts as a reliable separator of early- and late-type systems. The final set of stellar mass–half-light radius relations are reported for a variety of galaxy population subsets in 10 bands (ugrizZY JHKs) and are intended to provide a comprehensive low-z benchmark for the many ongoing high-z studies. Exploring the variation of the stellar mass–half-light radius relations with wavelength, we confirm earlier findings that galaxies appear more compact at longer wavelengths albeit at a smaller level than previously noted: at $10^{10}\mathcal {M_{\odot }}$ both spiral systems and ellipticals show a decrease in size of 13 per cent from g to Ks (which is near linear in log wavelength). Finally, we note that the sizes used in this work are derived from 2D Sérsic light profile fitting (using galfit3), i.e. elliptical semimajor half-light radii, improving on earlier low-z benchmarks based on circular apertures. [ABSTRACT FROM AUTHOR]

We present an estimate of the galaxy stellar mass function and its division by morphological type in the local (0.025 < z < 0.06) Universe. Adopting robust morphological classifications as previously presented (Kelvin et al.) for a sample of 3727 galaxies taken from the Galaxy And Mass Assembly survey, we define a local volume and stellar mass limited sub-sample of 2711 galaxies to a lower stellar mass limit of $\mathcal {M}=10^{9.0}\,{\rm M}_{{\odot }}$. We confirm that the galaxy stellar mass function is well described by a double-Schechter function given by $\mathcal {M}^{*}=10^{10.64}\,{\rm M}_{{\odot }}$, α1 = −0.43, $\phi _{1}^{*}=4.18\;\mathrm{dex}^{-1}\,\mathrm{Mpc}^{-3}$, α2 = −1.50 and $\phi _{2}^{*}=0.74\;\mathrm{dex}^{-1}\,\mathrm{Mpc}^{-3}$. The constituent morphological-type stellar mass functions are well sampled above our lower stellar mass limit, excepting the faint little blue spheroid population of galaxies. We find approximately $71{}_{-4}^{+3}$ per cent of the stellar mass in the local Universe is found within spheroid-dominated galaxies; ellipticals and S0-Sas. The remaining $29{}_{-3}^{+4}$ per cent falls predominantly within late-type disc-dominated systems, Sab-Scds and Sd-Irrs. Adopting reasonable bulge-to-total ratios implies that approximately half the stellar mass today resides in spheroidal structures, and half in disc structures. Within this local sample, we find approximate stellar mass proportions for E : S0-Sa : Sab-Scd : Sd-Irr of 34 : 37 : 24 : 5. [ABSTRACT FROM PUBLISHER]

We utilize the galaxy shape catalogue from the first-year data release of the Subaru Hyper Suprime-Cam (HSC) survey to study the dark matter content of galaxy groups in the Universe using weak lensing. We use galaxy groups from the Galaxy Mass and Assembly galaxy survey in approximately 100 sq. degrees of the sky that overlap with the HSC survey as lenses. We restrict our analysis to the 1587 groups with at least five members. We divide these groups into six bins each of group luminosity and group member velocity dispersion and measure the lensing signal with a signal-to-noise ratio of 55 and 51 for these two different selections, respectively. We use a Bayesian halo model framework to infer the halo mass distribution of our groups binned in the two different observable properties and constrain the power-law scaling relation and the scatter between mean halo masses and the two-group observable properties. We obtain a 5 per cent constraint on the amplitude of the scaling relation between halo mass and group luminosity with 〈 M 〉 = (0.81 ± 0.04) × 1014  h −1  M ⊙ for L grp = 1011.5  h −2  L ⊙, and a power-law index of α = 1.01 ± 0.07. We constrain the amplitude of the scaling relation between halo mass and velocity dispersion to be 〈 M 〉 = (0.93 ± 0.05) × 1014  h −1  M ⊙ for |$\sigma = 500\, {\rm km\, s}^{-1}$| and a power-law index to be α = 1.52 ± 0.10. However, these scaling relations are sensitive to the exact cuts applied to the number of group members. Comparisons with similar scaling relations from the literature show that our results are consistent and have significantly reduced errors. [ABSTRACT FROM AUTHOR]

We study the shapes of spatially integrated |$\rm{H}\, \small {{I}}$| emission-line profiles of galaxies in the eagle simulation using three separate measures of the profile's asymmetry. We show that the subset of eagle galaxies whose gas fractions and stellar masses are consistent with those in the xGASS survey also have similar |$\rm{H}\, \small {{I}}$| line asymmetries. Central galaxies with symmetric |$\rm{H}\, \small {{I}}$| line profiles typically correspond to rotationally supported |$\rm{H}\, \small {{I}}$| and stellar discs, but those with asymmetric line profiles may or may not correspond to dispersion-dominated systems. Galaxies with symmetric |$\rm{H}\, \small {{I}}$| emission lines are, on average, more gas rich than those with asymmetric lines, and also exhibit systematic differences in their specific star formation rates, suggesting that turbulence generated by stellar or AGN feedback may be one factor contributing to |$\rm{H}\, \small {{I}}$| line asymmetry. The line asymmetry also correlates strongly with the dynamical state of a galaxy's host dark matter halo: older, more relaxed haloes host more-symmetric galaxies than those hosted by unrelaxed ones. At fixed halo mass, asymmetric centrals tend to be surrounded by a larger number of massive subhaloes than their symmetric counterparts, and also experience higher rates of gas accretion and outflow. At fixed stellar mass, central galaxies have, on average, more symmetric |$\rm{H}\, \small {{I}}$| emission lines than satellites; for the latter, ram pressure and tidal stripping are significant sources of asymmetry. [ABSTRACT FROM AUTHOR]

We measure how the atomic gas (H i) fraction f H I = M H I M * of groups and pairs taken as single units vary with average stellar mass (〈 M *〉) and average star formation rate (〈SFR〉), compared to isolated galaxies. The H i 21 cm emission observation are from (i) archival ALFALFA survey data covering three fields from the GAMA survey (provides environmental and galaxy properties), and (ii) DINGO pilot survey data of one of those fields. The mean f H i for different units (groups/pairs/isolated galaxies) are measured in regions of the log(〈 M *〉)â€"log(〈SFR〉) plane, relative to the z ∼ 0 star-forming main sequence (SFMS) of individual galaxies, by stacking f H i spectra of individual units. For ALFALFA, f H i spectra of units are measured by extracting H i spectra over the full groups/pair areas and dividing by the total stellar mass of member galaxies. For DINGO, f H i spectra of units are measured by co-adding H i spectra of individual member galaxies, followed by division by their total stellar mass. For all units, the mean f H i decreases as we move to higher 〈 M *〉 along the SFMS and as we move from above the SFMS to below it at any 〈 M *〉. From the DINGO-based study, mean f H i in groups appears to be lower compared to isolated galaxies for all 〈 M *〉 along the SFMS. From the ALFALFA-based study, we find substantially higher mean f H i in groups compared to isolated galaxies (values for pairs being intermediate) for 〈 M *〉 ≲ 109.5 M ⊙, indicating the presence of substantial amounts of H i not associated with cataloged member galaxies in low mass groups. [ABSTRACT FROM AUTHOR]

ABSTRACT We present single-Sérsic two-dimensional (2D) model fits to 167 600 galaxies modelled independently in the ugrizYJHK bandpasses using reprocessed Sloan Digital Sky Survey Data Release Seven (SDSS DR7) and UKIRT Infrared Deep Sky Survey Large Area Survey imaging data available from the Galaxy And Mass Assembly (GAMA) data base. In order to facilitate this study we developed Structural Investigation of Galaxies via Model Analysis ( sigma), an r wrapper around several contemporary astronomy software packages including source extractor, psf extractor and galfit 3. sigma produces realistic 2D model fits to galaxies, employing automatic adaptive background subtraction and empirical point spread function measurements on the fly for each galaxy in GAMA. Using these results, we define a common coverage area across the three GAMA regions containing 138 269 galaxies. We provide Sérsic magnitudes truncated at 10 re which show good agreement with SDSS Petrosian and GAMA photometry for low Sérsic index systems ( n < 4), and much improved photometry for high Sérsic index systems ( n > 4), recovering as much as Δ m= 0.5 mag in the r band. We employ a K-band Sérsic index/ u− r colour relation to delineate the massive ( n > ∼2) early-type galaxies (ETGs) from the late-type galaxies (LTGs). The mean Sérsic index of these ETGs shows a smooth variation with wavelength, increasing by 30 per cent from g through K. LTGs exhibit a more extreme change in Sérsic index, increasing by 52 per cent across the same range. In addition, ETGs and LTGs exhibit a 38 and 25 per cent decrease, respectively, in half-light radius from g through K. These trends are shown to arise due to the effects of dust attenuation and stellar population/metallicity gradients within galaxy populations. [ABSTRACT FROM AUTHOR]

Using high-resolution Hubble Space Telescope imaging data, we perform a visual morphological classification of ∼36 000 galaxies at z < 1 in the deep extragalactic visible legacy survey/cosmological evolution survey region. As the main goal of this study, we derive the stellar mass function (SMF) and stellar mass density (SMD) sub-divided by morphological types. We find that visual morphological classification using optical imaging is increasingly difficult at z > 1 as the fraction of irregular galaxies and merger systems (when observed at rest-frame UV/blue wavelengths) dramatically increases. We determine that roughly two-thirds of the total stellar mass of the Universe today was in place by z ∼ 1. Double-component galaxies dominate the SMD at all epochs and increase in their contribution to the stellar mass budget to the present day. Elliptical galaxies are the second most dominant morphological type and increase their SMD by ∼2.5 times, while by contrast, the pure-disc population significantly decreases by |$\sim 85{{\ \rm per\ cent}}$|⁠. According to the evolution of both high- and low-mass ends of the SMF, we find that mergers and in situ evolution in discs are both present at z < 1, and conclude that double-component galaxies are predominantly being built by the in situ evolution in discs (apparent as the growth of the low-mass end with time), while mergers are likely responsible for the growth of ellipticals (apparent as the increase of intermediate/high-mass end). [ABSTRACT FROM AUTHOR]

Using high-resolution Hubble Space Telescope imaging data, we perform a visual morphological classification of ∼36 000 galaxies at z < 1 in the deep extragalactic visible legacy survey/cosmological evolution survey region. As the main goal of this study, we derive the stellar mass function (SMF) and stellar mass density (SMD) sub-divided by morphological types. We find that visual morphological classification using optical imaging is increasingly difficult at z > 1 as the fraction of irregular galaxies and merger systems (when observed at rest-frame UV/blue wavelengths) dramatically increases. We determine that roughly two-thirds of the total stellar mass of the Universe today was in place by z ∼ 1. Double-component galaxies dominate the SMD at all epochs and increase in their contribution to the stellar mass budget to the present day. Elliptical galaxies are the second most dominant morphological type and increase their SMD by ∼2.5 times, while by contrast, the pure-disc population significantly decreases by |$\sim 85{{\ \rm per\ cent}}$|⁠. According to the evolution of both high- and low-mass ends of the SMF, we find that mergers and in situ evolution in discs are both present at z < 1, and conclude that double-component galaxies are predominantly being built by the in situ evolution in discs (apparent as the growth of the low-mass end with time), while mergers are likely responsible for the growth of ellipticals (apparent as the increase of intermediate/high-mass end). [ABSTRACT FROM AUTHOR]

We present a revised measurement of the optical extragalactic background light (EBL), based on the contribution of resolved galaxies to the integrated galaxy light (IGL). The cosmic optical background radiation (COB), encodes the light generated by star formation, and provides a wealth of information about the cosmic star formation history (CSFH). We combine wide and deep galaxy number counts from the Galaxy And Mass Assembly survey (GAMA) and Deep Extragalactic VIsible Legacy Survey (DEVILS), along with the Hubble Space Telescope (HST) archive and other deep survey data sets, in nine multiwavelength filters to measure the COB in the range from 0.35   μ m to 2.2   μ m. We derive the luminosity density in each band independently and show good agreement with recent and complementary estimates of the optical-EBL from very high-energy (VHE) experiments. Our error analysis suggests that the IGL and γ-ray measurements are now fully consistent to within |$\sim 10{{\ \rm per\ cent}}$|⁠ , suggesting little need for any additional source of diffuse light beyond the known galaxy population. We use our revised IGL measurements to constrain the CSFH, and place amplitude constraints on a number of recent estimates. As a consistency check, we can now demonstrate convincingly, that the CSFH, stellar mass growth, and the optical-EBL provide a fully consistent picture of galaxy evolution. We conclude that the peak of star formation rate lies in the range 0.066–0.076 M⊙ yr−1 Mpc−3 at a lookback time of 9.1 to 10.9 Gyr. [ABSTRACT FROM AUTHOR]

We use KiDS weak lensing data to measure variations in mean halo mass as a function of several key galaxy properties (namely stellar colour, specific star formation rate, Sérsic index, and effective radius) for a volume-limited sample of GAMA galaxies in a narrow stellar mass range [ M * ∼ (2–5) × 1010 M⊙]. This mass range is particularly interesting, inasmuch as it is where bimodalities in galaxy properties are most pronounced, and near to the break in both the galaxy stellar mass function and the stellar-to-halo mass relation (SHMR). In this narrow mass range, we find that both size and Sérsic index are better predictors of halo mass than either colour or SSFR, with the data showing a slight preference for Sérsic index. In other words, we find that mean halo mass is more tightly correlated with galaxy structure than either past star formation history or current star formation rate. Our results lead to an approximate lower bound on the dispersion in halo masses among log  M * ≈ 10.5 galaxies: We find that the dispersion is ≳0.3 dex. This would imply either that offsets from the mean SHMR are closely coupled to size/structure or that the dispersion in the SHMR is larger than what past results have suggested. Our results thus provide new empirical constraints on the relationship between stellar and halo mass assembly at this particularly interesting mass range. [ABSTRACT FROM AUTHOR]

Satellite galaxies are commonly used as tracers to measure the line-of-sight (LOS)velocity dispersion (σLOS) of the dark matter halo associated with their central galaxy, and thereby to estimate the halo's mass. Recent observational dispersion estimates of the Local Group, including the Milky Way and M31, suggest σ ~50 km s-1, which is surprisingly low when compared to the theoretical expectation of σ ~100 km s-1 for systems of their mass. Does this pose a problem for Lambda cold dark matter (∧CDM)? We explore this tension using the SURFS suite of N-body simulations, containing over 10000 (sub)haloes with well tracked orbits. We test how well a central galaxy's host halo velocity dispersion can be recovered by sampling σLOS of subhaloes and surrounding haloes. Our results demonstrate that σLOS is biased mass proxy. We define an optimal window in νLOS and projected distance (Dp) - 0.5 ≲ Dp/Rvir ≲ 1.0 and νLOS ≲ 0.5Vesc, where Rvir is the virial radius and Vesc is the escape velocity - such that the scatter in LOS to halo dispersion is minimized - σLOS = (0.5 ± 0.1)σν, H. We argue that this window should be used to measure LOS dispersions as a proxy for mass, as it minimises scatter in the σLOS-Mvir relation. This bias also naturally explains the results from McConnachie (2012), who used similar cuts when estimating σLOS, LG, producing a bias of σLG = (0.44 ± 0.14)σν, H. We conclude that the Local Group's velocity dispersion does not pose a problem for ∧CDM and has a mass of logMLG,vir/M∡ = 12.0-2.0+0.8. [ABSTRACT FROM AUTHOR]

We present the Synthetic UniveRses For Surveys (SURFS) simulations, a set of N-body/Hydro simulations of the concordance A Cold Dark Matter (ACDM) cosmology. These simulations use Planck cosmology, contain up to 10 billion particles, and sample scales and halo masses down to 1 kpc and 108MQ. We identify and track haloes from z = 24 to today using a state-of-the-art 6D halo finder and merger tree builder. We demonstrate that certain properties of haloes merger trees are numerically converged for haloes composed of >100 particles. Haloes smoothly grow in mass, Vmax, with the mass history characterized by log M(a) a exp [-(a/ß)a], where a is the scale factor, a(M) ≈ 0.8 & ß(M) ≈ 0.024, with these parameters decreasing with decreasing halo mass. Subhaloes follow power-law cumulative mass and velocity functions, i.e. n(> f) a f~a with aM = 0.83 ± 0.01 and aVmax = 2.13 ± 0.03 for mass and velocity, respectively, independent of redshift, as seen in previous studies. The halo-tohalo scatter in amplitude is 0.9 dex. The number of subhaloes in a halo weakly correlates with a halo's concentration c and spin X:haloes of high c and low X have 60 per cent more subhaloes than similar mass haloes of low c and high X. High cadence tracking shows subhaloes are dynamic residents, with 25 per cent leaving their host halo momentarily, becoming a backsplash subhalo, and another 20 per cent changing hosts entirely, in agreement with previous studies. In general, subhaloes have elliptical orbits, e ≈ 0.6, with periods of 2.3 Gyrs. Subhaloes lose most of their mass at pericentric passage with mass loss rates of ~40 per cent Gyr-1. These catalogues will be made publicly available. [ABSTRACT FROM AUTHOR]

We use the energy-balance code MAGPHYS to determine stellar and dust masses, and dust corrected star formation rates for over 200 000 GAMA galaxies, 170 000 G10-COSMOS galaxies, and 200 000 3D-HST galaxies. Our values agree well with previously reported measurements and constitute a representative and homogeneous data set spanning a broad range in stellar-mass (108-1012 M温), dust-mass (106-109 M温), and star formation rates (0.01-100 M温yr-1), and over a broad redshift range (0.0 < z < 5.0). We combine these data to measure the cosmic star formation history (CSFH), the stellar-mass density (SMD), and the dust-mass density (DMD) over a 12 Gyr timeline. The data mostly agree with previous estimates, where they exist, and provide a quasi-homogeneous data set using consistent mass and star formation estimators with consistent underlying assumptions over the full time range. As a consequence our formal errors are significantly reduced when compared to the historic literature. Integrating our CSFH we precisely reproduce the SMD with an interstellar medium replenishment factor of 0.50 ± 0.07, consistent with our choice of Chabrier initial mass function plus some modest amount of stripped stellar mass. Exploring the cosmic dust density evolution, we find a gradual increase in dust density with lookback time. We build a simple phenomenological model from the CSFH to account for the dust-mass evolution, and infer two key conclusions: (1) For every unit of stellar mass which is formed 0.0065-0.004 units of dust mass is also formed. (2) Over the history of the Universe approximately 90-95 per cent of all dust formed has been destroyed and/or ejected. [ABSTRACT FROM AUTHOR]

We present the results of a VLT MUSE/FORS2 and Spitzer survey of a unique compact lensing cluster CLIO at z = 0.42, discovered through the GAMA survey using spectroscopic redshifts. Compact and massive clusters such as this are understudied, but provide a unique prospective on dark matter distributions and for finding background lensed high-z galaxies. The CLIO cluster was identified for follow-up observations due to its almost unique combination of high-mass and dark matter halo concentration, as well as having observed lensing arcs from ground-based images. Using dual band optical and infra-red imaging from FORS2 and Spitzer, in combination with MUSE optical spectroscopy we identify 89 cluster members and find background sources out to z = 6.49.We describe the physical state of this cluster, finding a strong correlation between environment and galaxy spectral type. Under the assumption of an NFW profile, we measure the total mass of CLIO to be M200 = (4.49 ± 0.25) × 1014 M☉. We build and present an initial strong-lensing model for this cluster, and measure a relatively low intracluster light (ICL) fraction of 7.21 ± 1.53 per cent through galaxy profile fitting. Due to its strong potential for lensing background galaxies and its low ICL, the CLIO cluster will be a target for our 110 h James Webb Space Telescope 'Webb Medium-Deep Field' (WMDF) GTO program. [ABSTRACT FROM AUTHOR]

Our nearest large cosmological neighbour, the Andromeda galaxy (M31), is a dynamical system, and an accurate measurement of its total mass is central to our understanding of its assembly history, the life-cycles of its satellite galaxies, and its role in shaping the Local Group environment. Here, we apply a novel approach to determine the dynamical mass of M31 using high-velocity Planetary Nebulae, establishing a hierarchical Bayesian model united with a scheme to capture potential outliers and marginalize over tracers unknown distances. With this, we derive the escape velocity run of M31 as a function of galactocentric distance, with both parametric and non-parametric approaches. We determine the escape velocity of M31 to be 470 ± 40 km s-1 at a galactocentric distance of 15 kpc, and also, derive the total potential of M31, estimating the virial mass and radius of the galaxy to be 0.8 ± 0.1 × 1012M☉ and 240 ± 10 kpc, respectively. Our M31 mass is on the low side of the measured range, this supports the lower expected mass of the M31-MilkyWay system from the timing and momentum arguments, satisfying the HI constraint on circular velocity between 10 ☉ R/ kpc < 35, and agreeing with the stellar mass Tully-Fisher relation. To place these results in a broader context, we compare them to the key predictions of the ☉CDM cosmological paradigm, including the stellar-mass-halo-mass and the dark matter halo concentration-virial mass correlation, and finding it to be an outlier to this relation. [ABSTRACT FROM AUTHOR]

Our nearest large cosmological neighbour, the Andromeda galaxy (M31), is a dynamical system and an accurate measurement of its total mass is central to our understanding of its assembly history, the life-cycles of its satellite galaxies and its role in shaping the Local Group environment. Here, we apply a novel approach to determine the dynamical mass of M31 using high-velocity Planetary Nebulae, establishing a hierarchical Bayesian model united with a scheme to capture potential outliers and marginalize over tracers unknown distances. With this, we derive the escape velocity run of M31 as a function of galactocentric distance, with both parametric and non-parametric approaches. We determine the escape velocity of M31 to be 470 ± 40 km s-1 at a galactocentric distance of 15 kpc and also, derive the total potential of M31, estimating the virial mass and radius of the galaxy to be 0.8 ± 0.1 x1012M☉ and 240 ± 10 kpc, respectively. Our M31 mass is on the low side of the measured range, this supports the lower expected mass of the M31-MilkyWay system from the timing and momentum arguments, satisfying the HI constraint on circular velocity between 10 ≲R/ kpc < 35 and agreeing with the stellar mass Tully-Fisher relation. To place these results in a broader context, we compare them to the key predictions of the ☉CDM cosmological paradigm, including the stellar-mass-halo-mass and the dark matter halo concentration-virial mass correlation and finding it to be an outlier to this relation. [ABSTRACT FROM AUTHOR]