Evidence for strong evolution in galaxy environmental quenching efficiency between z = 1.6 and z = 0.9
Julie B. Nantais, Adam Muzzin, Remco F. J. van der Burg, Gillian Wilson, Chris Lidman, Ryan Foltz, Andrew DeGroot, Allison Noble, Michael C. Cooper, Ricardo Demarco
We analyse the evolution of environmental quenching efficiency, the fraction of quenched cluster galaxies that would be star-forming if they were in the field, as a function of redshift in 14 spectroscopically confirmed galaxy clusters with 0.87 < z < 1.63 from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS). The clusters are the richest in the survey at each redshift. Passive fractions rise from $42_{-13}^{+10}$\% at z ~ 1.6 to $80_{-9}^{+12}$\% at z ~ 1.3 and $88_{-3}^{+4}$\% at z < 1.1, outpacing the change in passive fraction in the field. Environmental quenching efficiency rises dramatically from $16_{-19}^{+15}$ at z ~ 1.6 to $62_{-15}^{+21}\% at z ~ 1.3 and $73_{-7}^{+8}$\% at z $\lesssim$ 1.1. This work is the first to show direct observational evidence for a rapid increase in the strength of environmental quenching in galaxy clusters at z ~ 1.5, where simulations show cluster-mass halos undergo non-linear collapse and virialisation.
Quenching is a key topic in exploring the formation and evolution of galaxies. In this work, we study the quenching rate, i.e., the variation in the fraction of quenched galaxies per unit time, of the Illustris-1 simulation. By building the quenched fraction function $f(m,ρ, t)$ of each snapshot in the simulation, we derive an accurate form of quenching rate as $\Re_q=df(m,ρ,t)/dt$. According to the analytic expression of the quenching rate $\Re_q$, we split it into four components: mass quenching, environmental quenching, intrinsic mass quenching and intrinsic environmental quenching. The pre…
In the local Universe, there is a strong division in the star-forming properties of low-mass galaxies, with star formation largely ubiquitous amongst the field population while satellite systems are predominantly quenched. This dichotomy implies that environmental processes play the dominant role in suppressing star formation within this low-mass regime (${M}_{\star} \sim 10^{5.5-8}~{\rm M}_{\odot}$). As shown by observations of the Local Volume, however, there is a non-negligible population of passive systems in the field, which challenges our understanding of quenching at low masses. By appl…
One of the challenges in understanding the quenching processes for galaxies is connecting progenitor star-forming populations to their descendant quiescent populations over cosmic time. Here we attempt a novel approach to this challenge by assuming that the underlying stellar mass distribution of galaxies is not significantly altered during environmental quenching processes that solely affect the gas content of cluster galaxies, such as strangulation and ram-pressure stripping. Using the deep, high-resolution photometry of the Hubble Frontier Fields, we create resolved stellar mass maps for bo…
We present new analysis from the GEEC2 spectroscopic survey of galaxy groups at $0.8<z<1$. Our previous work revealed an intermediate population between the star-forming and quiescent sequences and a strong environmental dependence in the fraction of quiescent galaxies. Only $\sim5$ per cent of star-forming galaxies in both the group and field sample show a significant enhancement in star formation, which suggests that quenching is the primary process in the transition from the star-forming to the quiescent state. To model the environmental quenching scenario, we have tested the use of differe…
We use the semi-analytic model of galaxy formation SAG to study the relevance of mass and environmental quenching on satellite galaxies. We find that environmental processes dominate the star formation (SF) quenching of low-mass satellites ($M_{\star} \lesssim 10^{10.5}\, {\rm M}_{\odot}$), whereas high-mass galaxies typically quench as centrals. High-mass galaxies that remain actively forming stars while being accreted are found to be mainly affected by mass quenching after their first infall. For a given stellar mass, our model predicts SF quenching to be less efficient in low-mass haloes bo…
Using a sample of 4 galaxy clusters at $1.35 < z < 1.65$ and 10 galaxy clusters at $0.85 < z < 1.35$, we measure the environmental quenching timescale, $t_Q$, corresponding to the time required after a galaxy is accreted by a cluster for it to fully cease star formation. Cluster members are selected by a photometric-redshift criterion, and categorized as star-forming, quiescent, or intermediate according to their dust-corrected rest-frame colors and magnitudes. We employ a "delayed-then-rapid" quenching model that relates a simulated cluster mass accretion rate to the observed numbers of each …
By combining H$α$ flux measurements from the Sloan Digital Sky Survey (SDSS) with UV flux observations from the Galaxy Evolution Explorer (GALEX), we examine the environmental dependence (through central/satellite distinction) of the rapid quenching and rejuvenation of galaxies. H$α$ emissions trace the most massive stars, thereby indicating star-formation on timescales of $\sim 10$ Myr, while UV emission traces star-formation on timescales of $\sim 100$ Myr. These varying timescales are exploited to probe the most recent star-formation histories of galaxies. In this work, we define a class of…
We investigate the connection between environment and the different quenching channels that galaxies are prone to follow in the rest-frame NUVrK colour diagram, as identified by Moutard et al. (2016b). Namely, the fast quenching channel followed by $young$ low-mass galaxies and the slow quenching channel followed by $old$ high-mass ones. We make use of the >22 deg$^2$ covered the VIPERS Multi-Lambda Survey (VIPERS-MLS) to select a galaxy sample complete down to stellar masses of $M_* > 10^{9.4} M_\odot$ at $z < 0.65$ ($M_* > 10^{8.8} M_\odot$ at $z < 0.5$) and including 33,500 (43,000) quiesce…
We study galactic star-formation activity as a function of environment and stellar mass over 0.5<z<2.0 using the FourStar Galaxy Evolution (ZFOURGE) survey. We estimate the galaxy environment using a Bayesian-motivated measure of the distance to the third nearest neighbor for galaxies to the stellar mass completeness of our survey, $\log(M/M_\odot)>9 (9.5)$ at z=1.3 (2.0). This method, when applied to a mock catalog with the photometric-redshift precision ($σ_z / (1+z) \lesssim 0.02$), recovers galaxies in low- and high-density environments accurately. We quantify the environmental quenching e…
We report evidence of environmental quenching among galaxies at redshift ~ 2, namely the probability that a galaxy quenches its star formation activity is enhanced in the regions of space in proximity of other quenched, more massive galaxies. The effect is observed as strong clustering of quiescent galaxies around quiescent galaxies on angular scales θ< 20 arcsec, corresponding to a proper(comoving) scale of 168 (502) kpc at z = 2. The effect is observed only for quiescent galaxies around other quiescent galaxies; the probability to find star-forming galaxies around quiescent or around star-fo…
Using ~5000 spectroscopically-confirmed galaxies drawn from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey we investigate the relationship between color and galaxy density for galaxy populations of various stellar masses in the redshift range $0.55 \le z \le 1.4$. The fraction of galaxies with colors consistent with no ongoing star formation ($f_q$) is broadly observed to increase with increasing stellar mass, increasing galaxy density, and decreasing redshift, with clear differences observed in $f_q$ between field and group/cluster galaxies at the highest r…
Does the environment of a galaxy directly influence the quenching history of a galaxy? Here we investigate the detailed morphological structures and star formation histories of a sample of SDSS group galaxies with both classifications from Galaxy Zoo 2 and NUV detections in GALEX. We use the optical and NUV colours to infer the quenching time and rate describing a simple exponentially declining SFH for each galaxy, along with a control sample of field galaxies. We find that the time since quenching and the rate of quenching do not correlate with the relative velocity of a satellite but are cor…
Recently a number of studies have found a similarity between the passive fraction of central and satellite galaxies when controlled for both stellar and halo mass. These results suggest that the quenching processes that affect galaxies are largely agnostic to central/satellite status, which contradicts the traditional picture of increased satellite quenching via environmental processes such as stripping, strangulation and starvation. Here we explore this further using the Galaxy And Mass Assembly (GAMA) survey which extends to ~2dex lower in stellar mass than SDSS, is more complete for closely…
We investigate the environmental quenching of galaxies, especially those with stellar masses (M*)$<10^{9.5} M_\odot$, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, which is a demonstration of environmental quenching. We use CANDELS data to test {\it whether or not} such a dwarf QG--massive central galaxy connection exists beyond the local universe. To this purpose, we only need a statistically representative, rather than a complete, sample of low-mass galaxies, which enables our study to $z\gtrsim1.5$. …
A clear transition feature of galaxy quenching is identified in the multi-parameter space of stellar mass ($M_*$), bulge to total mass ratio ($B/T_{\rm m}$), halo mass ($M_{\rm h}$) and halo-centric distance ($r/r_{180}$). For given halo mass, the characteristic stellar mass ($M_{*, \rm ch}$) for the transition is about one-fifth of that of the corresponding central galaxy, and almost independent of $B/T_{\rm m}$. Once $B/T_{\rm m}$ is fixed, the quenched fraction of galaxies with $M_{*} < M_{*, \rm ch}$ increases with $M_{\rm h}$, but decreases with $M_*$ in the inner part of halos ($r/r_{180…
Galaxies that have fallen into massive haloes may no longer be able to accrete gas from their surroundings, a process referred to as 'starvation' or 'strangulation' of satellites. We study the environmental dependence of gas accretion onto galaxies using the cosmological, hydrodynamical EAGLE simulation. We quantify the dependence of gas accretion on stellar mass, redshift, and environment, using halo mass and galaxy overdensity as environmental indicators. We find a strong suppression, by many orders of magnitude, of the gas accretion rate in dense environments, primarily for satellite galaxi…
It has long been known that environment has a large effect on star formation in galaxies. There are several known plausible mechanisms to remove the cool gas needed for star formation, such as strangulation, harassment and ram-pressure stripping.It is unclear which process is dominant, and over what range of stellar mass. In this paper, we find evidence for suppression of the cross-correlation function between massive galaxies and less massive star-forming galaxies, giving a measure of how less likely a galaxy is to be star-forming in the vicinity of a more massive galaxy. We develop a formali…
We examine the quenched fraction of central and satellite galaxies as a function of galaxy stellar mass, halo mass, and the matter density of their large scale environment. Matter densities are inferred from our ELUCID simulation, a constrained simulation of local Universe sampled by SDSS, while halo masses and central/satellite classification are taken from the galaxy group catalog of Yang et al. The quenched fraction for the total population increases systematically with the three quantities. We find that the `environmental quenching efficiency', which quantifies the quenched fraction as fun…
Galaxies that are several virial radii beyond groups/clusters show preferentially quiescent star formation rates. Using a galaxy group/cluster catalog from the Sloan Digital Sky Survey, together with a cosmological N-body simulation, we examine the origin of this environmental quenching beyond the virial radius. Accounting for the clustering of groups/clusters, we show that central galaxies show enhanced SFR quenching out to 2.5 virial radii beyond groups/clusters, and we demonstrate that this extended environmental enhancement can be explained simply by 'ejected' satellite galaxies that orbit…
The kinematic imprinting of environmental quenching in $z<0.2$ galaxies
European Southern Observatory（欧洲南方天文台）；Excellence Cluster ORIGINS（ORIGINS卓越集群）；School of Physics and Astronomy, University of Nottingham（诺丁汉大学物理与天文学学院）；Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院物理研究所）；INAF – Padua Astronomical Observatory（意大利国家天体物理研究所帕多瓦天文台）；INAF – Astronomical Observatory of Trieste（意大利国家天体物理研究所的里雅斯特天文台）；INAF – Arcetri Astrophysical Observatory（意大利国家天体物理研究所阿切特里天文台）；International Centre for Radio Astronomy Research (ICRAR), University of Western Australia（西澳大利亚大学国际射电天文研究中心）
The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band Halpha+[NII] imaging survey of the Virgo cluster carried out with MegaCam at the Canada-French-Hawaii telescope (CFHT). We use a new set of data extracted from VESTIGE to study the impact of the hostile cluster environment on the star formation process down to the scale of HII regions (~ 50 pc). HII regions are identified and their parameters measured using the HIIphot code on a sample of 114 late-type galaxies spanning a wide range in morphological type (Sa-Sd, Im, BCD), stellar mass (10^6.5 <= M_star…
We present ALMA Band 6 (nu=233GHz, lambda=1.3mm) continuum observations towards 68 'normal' star-forming galaxies within two Coma-like progenitor structures at z=2.10 and 2.47, from which ISM masses are derived, providing the largest census of molecular gas mass in overdense environments at these redshifts. Our sample comprises galaxies with a stellar mass range of 1x10^9M_sun - 4x10^11M_sun with a mean M_*~6x10^10M_sun. Combining these measurements with multiwavelength observations and SED modeling, we characterize the gas mass fraction and the star formation efficiency, and infer the impact …
We use stellar mass functions to study the properties and the significance of quenching through major galaxy mergers. In addition to SDSS DR7 and Galaxy Zoo 1 data, we use samples of visually selected major galaxy mergers and post merger galaxies. We determine the stellar mass functions of the stages that we would expect major merger quenched galaxies to pass through on their way from the blue cloud to the red sequence: 1: major merger, 2: post merger, 3: blue early type, 4: green early type and 5: red early type. Based on the similar mass function shapes we conclude that major mergers are lik…
We re-examine the fraction of low-redshift Sloan Digital Sky Survey satellites and centrals in which star formation has been quenched, using the environment quenching efficiency formalism that separates out the dependence of stellar mass. We show that the centrals of the groups containing the satellites are responding to the environment in the same way as their satellites (at least for stellar masses above 10^10.3 Msun), and that the well-known differences between satellites and the general set of centrals arise because the latter are overwhelmingly dominated by isolated galaxies. The widespre…
Galaxies can be classified as passive ellipticals or star-forming discs. Ellipticals dominate at the high end of the mass range, and therefore there must be a mechanism responsible for the quenching of star-forming galaxies. This could either be due to the secular processes linked to the mass and star formation of galaxies or to external processes linked to the surrounding environment. In this paper, we analytically model the processes that govern galaxy evolution and quantify their contribution. We have specifically studied the effects of mass quenching, gas stripping, and mergers on galaxy q…
We utilize the HSC CAMIRA cluster catalog and the photo-$z$ galaxy catalog constructed in the HSC wide field (S16A), covering $\sim$ 174 deg$^{2}$, to study the star formation activity of galaxies in different environments over 0.2 $<$ $z$ $<$ 1.1. We probe galaxies down to $i \sim$ 26, corresponding to a stellar mass limit of log$_{10}$(M$_*$/M$_{\odot}$) $\sim$ 8.2 and $\sim$ 8.6 for star-forming and quiescent populations, respectively, at $z$ $\sim$ 0.2. The existence of the red sequence for low stellar mass galaxies in clusters suggests that the environmental quenching persists to halt the…
The star formation and gas content of satellite galaxies around the Milky Way (MW) and Andromeda (M31) are depleted relative to more isolated galaxies in the Local Group (LG) at fixed stellar mass. We explore the environmental regulation of gas content and quenching of star formation in $z=0$ galaxies at $M*=10^{5-10}\rm{M}_{\odot}$ around 14 MW-mass hosts from the FIRE-2 simulations. Lower-mass satellites ($M*\lesssim10^7\rm{M}_{\odot}$) are mostly quiescent and higher-mass satellites ($M*\gtrsim10^8\rm{M}_{\odot}$) are mostly star-forming, with intermediate-mass satellites ($M*\approx10^{7-8…
We study the structural and environmental dependence of the star formation on the plane of stellar mass versus central core density ($Σ_{\rm 1\ kpc}$) in the nearby universe. We study the central galaxies in the sparse environment and find a characteristic population-averaged $\rm Σ_{1\ kpc} \sim 10^9-10^{9.2}\ M_{\odot}\ kpc^{-2}$, above which quenching is operating. This $\rm Σ^{crit}_{1\ kpc}$ only weakly depends on the stellar mass, suggesting that the mass-quenching of the central galaxies is more closely related to the processes that operate in the central regions than over the entire ga…
In the Local Group, nearly all of the dwarf galaxies (M_star < 10^9 M_sun) that are satellites within 300 kpc (the virial radius) of the Milky Way (MW) and Andromeda (M31) have quiescent star formation and little-to-no cold gas. This contrasts strongly with comparatively isolated dwarf galaxies, which are almost all actively star-forming and gas-rich. This near dichotomy implies a rapid transformation of satellite dwarf galaxies after falling into the halos of the MW or M31. We combine the observed quiescent fractions for satellites of the MW and M31 with the infall times of satellites from th…
Galaxy quenching is a critical step in galaxy evolution. In this work, we present a statistical study of galaxy quenching in 17 cluster candidates at 0.5<z<1.0 in the COSMOS field. We selected cluster members with a wide range of stellar mass and environment to study their mass and environment dependence. Member galaxies are classified into star-forming, quiescent and recently-quenched galaxies (RQG) using the rest-frame UVJ diagram. We further separated fast and slow quenching RQGs by model evolutionary tracks on the UVJ diagram. We defined the quenching efficiency as the ratio of RQGs over s…
We take advantage of an analytic model of galaxy formation coupled to the merger tree of an N-body simulation to study the roles of environment and stellar mass in the quenching of galaxies. The model has been originally set in order to provide the observed evolution of the stellar mass function as well as reasonable predictions of the star formation rate-stellar mass relation, from high redshift to the present time. We analyse the stellar mass and environmental quenching efficiencies and their dependence on stellar mass, halo mass (taken as a proxy for the environment) and redshift. Our analy…
We calculate the star formation quenching timescales in green valley galaxies at intermediate redshifts ($z\sim0.5-1$) using stacked zCOSMOS spectra of different galaxy morphological types: spheroidal, disk-like, irregular and merger, dividing disk-like galaxies further into unbarred, weakly-barred and strongly-barred, assuming a simple exponentially-decaying star formation history model and based on the H$_δ$ absorption feature and the $4000$ Å~break. We find that different morphological types present different star formation quenching timescales, reinforcing the idea that the galaxy morpholo…
We study environmental quenching using the spatial distribution of current star-formation and stellar population ages with the full SAMI Galaxy Survey. By using a star-formation concentration index [C-index, defined as log10(r_{50,Halpha}/r_{50,cont})], we separate our sample into regular galaxies (C-index>-0.2) and galaxies with centrally concentrated star-formation (SF-concentrated; C-index<-0.2). Concentrated star-formation is a potential indicator of galaxies currently undergoing `outside-in' quenching. Our environments cover ungrouped galaxies, low-mass groups (M_200<10^12.5 M_sun), high-…
We measure the rate of environmentally-driven star formation quenching in galaxies at $z\sim 1$, using eleven massive ($M\approx 2\times10^{14}\,\mathrm{M}_\odot$) galaxy clusters spanning a redshift range $1.0<z<1.4$ from the GOGREEN sample. We identify three different types of transition galaxies: "green valley" (GV) galaxies identified from their rest-frame $(NUV-V)$ and $(V-J)$ colours; "blue quiescent" (BQ) galaxies, found at the blue end of the quiescent sequence in $(U-V)$ and $(V-J)$ colour; and spectroscopic post-starburst (PSB) galaxies. We measure the abundance of these galaxies as …
Dissecting the mass quenching in TNG50: Galaxy size determines the quenching mode
University of Science and Technology of China（中国科学技术大学）；Peking University（北京大学）；Durham University（杜伦大学）；Institute of Deep Space Sciences, Deep Space Exploration Laboratory（深空科学研究所，深空探测实验室）
We present the stellar mass functions (SMFs) of passive and star-forming galaxies with a limiting mass of 10$^{10.1}$ M$_{\odot}$ in four spectroscopically confirmed Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) galaxy clusters at 1.37 $<$ z $<$ 1.63. The clusters have 113 spectroscopically confirmed members combined, with 8-45 confirmed members each. We construct $Ks$-band-selected photometric catalogs for each cluster with an average of 11 photometric bands ranging from $u$ to 8 $μ$m. We compare our cluster galaxies to a field sample derived from a similar $Ks$-band-selected…
We present high spatial resolution imaging of the CO(1-0) line from the Karl G. Jansky Very Large Array (VLA) of COSMOS27289, a massive, compact star forming galaxy at z=2.234. This galaxy was selected to be structurally similar to z~2 passive galaxies. Our previous observations showed that it is very gas-poor with respect to typical star-forming galaxies at these redshifts, consistent with a rapid transition to quiescence as the molecular gas is depleted. The new data show that both the molecular gas fraction f_H2 = M_H2/M_star and the molecular gas depletion time t_dep = M_H2/SFR are lower i…
We study the effects of local environment and stellar mass on galaxy properties using a mass complete sample of quiescent and star-forming systems in the COSMOS field at $z\lesssim$ 3. We show that at $z\lesssim$ 1, the median star-formation rate (SFR) and specific SFR (sSFR) of all galaxies depend on environment, but they become independent of environment at $z\gtrsim$ 1. However, we find that only for \textit{star-forming} galaxies, the median SFR and sSFR are similar in different environments, regardless of redshift and stellar mass. We find that the quiescent fraction depends on environmen…
We explore the radial distribution of star formation in galaxies in the SAMI Galaxy Survey as a function of their local group environment. Using a sample of galaxies in groups (with halo masses less than $ \simeq 10^{14} \, \mathrm{M_{\odot}}$) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups ($M_{G} > 10^{12.5} \, \mathrm{M_{\odot}}$). The mean integrated specific star formation rate of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or that are ungrouped, with $Δ\log(sSFR/\mathrm{yr^{-1}}) = 0.…
Environment is one of the primary drivers of galaxy evolution; via multiple mechanisms, it can control the critical process of transforming galaxies from star forming to quiescent, commonly termed "quenching". Despite its importance, however, we still do not have a clear view of how environmentally-driven quenching proceeds even in the most extreme environments: galaxy clusters and their progenitor proto-clusters. Recent advances in infrared capabilities have enabled transformative progress not only in the identification of these structures but in detailed analyses of quiescence, obscured star…
We study the star formation histories (SFHs) and mass-weighted ages of 331 UVJ-selected quiescent galaxies in 11 galaxy clusters and in the field at 1<z<1.5 from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. We determine the SFHs of individual galaxies by simultaneously fitting rest-frame optical spectroscopy and broadband photometry to stellar population models. We confirm that the SFHs are consistent with more massive galaxies having on average earlier formation times. Comparing galaxies found in massive clusters with those in the field, we find galaxies wi…
To explore the effect of environment on star-formation and morphological transformation of high-redshift galaxies, we present a robust estimation of localized galaxy overdensity using a density estimator within the Bayesian probability framework.The maps of environmental overdensity at $0.5< z< 2.5$ are constructed for the five CANDELS fields. In general, the quiescent fraction increases with overdensity and stellar mass. Stellar mass dominates the star formation quenching for massive galaxies, while environmental quenching tends to be more effective for the low-mass galaxies at $0.5< z < 1$. …
We present a population study of the star formation history of 1244 Type 2 AGN host galaxies, compared to 6107 inactive galaxies. A Bayesian method is used to determine individual galaxy star formation histories, which are then collated to visualise the distribution for quenching and quenched galaxies within each population. We find evidence for some of the Type 2 AGN host galaxies having undergone a rapid drop in their star formation rate within the last 2 Gyr. AGN feedback is therefore important at least for this population of galaxies. This result is not seen for the quenching and quenched …
We present direct observational evidence for star formation quenching in galaxy groups in the redshift range 0<z<2.5. We utilize a large sample of nearly 6000 groups, selected by fixed cumulative number density from three photometric catalogs, to follow the evolving quiescent fractions of central and satellite galaxies over roughly 11 Gyr. At z~0, central galaxies in our sample range in stellar mass from Milky Way/M31 analogs (M=6.5x10^10 M\solar) to nearby massive ellipticals (M=1.5x10^11 M\solar). Satellite galaxies in the same groups reach masses as low as twice that of the Large Magellanic…
We study the quenching of star formation as a function of redshift, environment and stellar mass in the galaxy formation simulations of Henriques et al. (2015), which implement an updated version of the Munich semi-analytic model (L-GALAXIES) on the two Millennium Simulations after scaling to a Planck cosmology. In this model massive galaxies are quenched by AGN feedback depending on both black hole and hot gas mass, and hence indirectly on stellar mass. In addition, satellite galaxies of any mass can be quenched by ram-pressure or tidal stripping of gas and through the suppression of gaseous …
We use photometric redshifts and statistical background subtraction to measure stellar mass functions in galaxy group-mass ($4.5-8\times10^{13}~\mathrm{M}_\odot$) haloes at $1<z<1.5$. Groups are selected from COSMOS and SXDF, based on X-ray imaging and sparse spectroscopy. Stellar mass ($M_{\mathrm{stellar}}$) functions are computed for quiescent and star-forming galaxies separately, based on their rest-frame $UVJ$ colours. From these we compute the quiescent fraction and quiescent fraction excess (QFE) relative to the field as a function of $M_{\mathrm{stellar}}$. QFE increases with $M_{\math…
