In this work, we analyze the role of AGN feedback in quenching star formation for massive, central galaxies in the local Universe. In particular, we compare the prediction of two semi-analytic models (L-GALAXIES and SAGE) featuring different schemes for AGN feedback, with the SDSS DR7 taking advantage of a novel technique for identifying central galaxies in an observational dataset. This enables us to study the correlation between the model passive fractions, which is predicted to be suppressed by feedback from an AGN, and the observed passive fractions in an observationally motivated parameter space. While the passive fractions for observed central galaxies show a good correlation with stellar mass and bulge mass, passive fractions in L-GALAXIES correlate with the halo and black hole mass. For SAGE, the passive fraction correlate with the bulge mass as well. Among the two models, SAGE has a smaller scatter in the black hole - bulge mass (M_BH - M_Bulge) relation and a slope that agrees better with the most recent observations at z \sim 0. Despite the more realistic prescription of radio mode feedback in SAGE, there are still tensions left with the observed passive fractions and the distribution of quenched galaxies. These tensions may be due to the treatment of galaxies living in non-resolved substructures and the resulting higher merger rates that could bring cold gas which is available for star formation.
Feedback from accreting supermassive black holes (SMBHs) is thought to be a primary driver of quenching in massive galaxies, but the best way to implement SMBH physics into galaxy formation simulations remains ambiguous. As part of the Feedback in Realistic Environments (FIRE) project, we explore the effects of different modeling choices for SMBH accretion and feedback in a suite of $\sim500$ cosmological zoom-in simulations across a wide range of halo mass (10^10-10^13 Msun). Within the suite, we vary the numerical schemes for BH accretion and feedback, the accretion efficiency, and the stren…
Recent observations suggested that star formation quenching in galaxies is related to galaxy structure. Here we propose a new mechanism to explain the physical origin of this correlation. We assume that while quiescent galaxies are maintained quenched by a feedback mechanism, cooling flows in the hot halo gas can still develop intermittently. We study cooling flows in a large suite of around 90 hydrodynamic simulations of an isolated galaxy group, and find that the flow development depends significantly on the gravitational potential well in the central galaxy. If the galaxy's gravity is not s…
The evolution of satellite galaxies is shaped by their constant interaction with the circum galactic medium surrounding central galaxies, which in turn may be affected by gas and energy ejected from the central supermassive black hole. However, the nature of this coupling between black holes and galaxies is highly debated and observational evidence remains scarce. Here we report an analysis of archival data on 124,163 satellite galaxies in the potential wells of 29,631 dark matter halos with masses between 10$^{12}$ and $10^{14}$ solar masses. We find that quiescent satellites are relatively l…
The average star formation rate (SFR) in galaxies has been declining since redshift of 2. A fraction of galaxies quench and become quiescent. We constrain two key properties of the quenching process: the quenching time scale and the quenching rate among galaxies. We achieve this by analyzing the galaxy number density profile in NUV-u color space and the distribution in NUV-u v.s. u-i color-color diagram with a simple toy-model framework. We focus on galaxies in three mass bins between 10 to 10 and 10 to 10.6 solar mass. In the NUV-u v.s. u-i color-color diagram, the red u-i galaxies exhibit a …
Galaxy mergers are traditionally one of the favoured mechanisms for quenching star formation. To test this paradigm in the context of modern cosmological simulations, we use the IllustrisTNG simulation to investigate the impact of individual merger events on quenching (i.e. star formation rate at least 3sig below the star-forming main sequence) within 500Myr after the coalescence phase.The rate of quenching amongst recently merged galaxies is compared with a control sample that is matched in redshift, stellar mass, star formation rate (SFR), black hole mass and environment.We find quenching to…
The suppression of star formation in the inner kiloparsec regions of barred disk galaxies due to the action of bars is known as bar quenching. We investigate here the significance of bar quenching in the global quenching of star formation in the barred galaxies and their transformation to passive galaxies in the local Universe. We do this by measuring the offset of quenched barred galaxies from star-forming main sequence galaxies in the star formation rate-stellar mass plane and comparing it with the length of the bar, which is considered as a proxy of bar quenching. We constructed the star fo…
We investigate the connection between X-ray and radio-loud AGNs and the physical properties of their evolved and massive host galaxies, focussing on the mass-related quenching channel followed by $\mathcal{M}^\star (\simeq 10^{10.6} M_\odot)$ galaxies in the rest-frame NUVrK colour diagram at $0.2 < z < 0.5$. While our results confirm that (1) radio-loud AGNs are predominantly hosted by already-quenched and very massive ($M_*>10^{11}M_\odot$) galaxies, ruling out their feedback as a primary driver of $\mathcal{M}^\star$ galaxy quenching, we found that (2) X-ray AGNs affected by heavy obscurati…
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…
Central galaxies make up the majority of the galaxy population, including the majority of the quiescent population at $\mathcal{M}_* > 10^{10}\mathrm{M}_\odot$. Thus, the mechanism(s) responsible for quenching central galaxies plays a crucial role in galaxy evolution as whole. We combine a high resolution cosmological $N$-body simulation with observed evolutionary trends of the "star formation main sequence," quiescent fraction, and stellar mass function at $z < 1$ to construct a model that statistically tracks the star formation histories and quenching of central galaxies. Comparing this mode…
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 used the time since infall (TSI) of galaxies, obtained from the Yonsei Zoom-in Cluster Simulation, and the star formation rate (SFR) from the Sloan Digital Sky Survey (SDSS) Data Release 10 to study how quickly star formation of disk galaxies is quenched in cluster environments. We first confirm that both simulated and observed galaxies are consistently distributed in phase space. We then hypothesize that the TSI and SFR are causally connected; thus, both the TSI and SFR of galaxies at each position of phase space can be associated through abundance matching. Using a flexible model, we deri…
(Abridged) We explore 7 clusters from LoCuSS at z~0.2 with spectra of 1965 cluster members from the ACReS Hectospec survey covering a region which corresponds to about three virial radii for each cluster. We measure fluxes of five emission lines of cluster members enabling us to unambiguously derive O/H gas metallicities, and also SFRs from extinction corrected Halpha fluxes. We compare our cluster galaxy sample with a field sample of 705 galaxies at similar redshifts observed with Hectospec. We find that star-forming cluster and field galaxies show similar median specific SFRs in a given mass…
We identify the intrinsic dependence of star formation quenching on a variety of galactic and environmental parameters, utilizing a machine learning approach with Random Forest classification. We have previously demonstrated the power of this technique to isolate causality, not mere correlation, in complex astronomical data. First, we analyze three cosmological hydrodynamical simulations (Eagle, Illustris, and IllustrisTNG), selecting snapshots spanning the bulk of cosmic history from comic noon ($z \sim 2$) to the present epoch, with stellar masses in the range $9 < \log(M_*/M_{\odot}) < 12$.…
We use HI and H2 global gas measurements of galaxies from xGASS and xCOLD GASS to investigate quenching paths of galaxies below the star formation main sequence (SFMS). We show that the population of galaxies below the SFMS is not a 1:1 match with the population of galaxies below the HI and H2 gas fraction scaling relations. Some galaxies in the transition zone (TZ) 1-sigma below the SFMS can be as HI-rich as those in the SFMS, and have on average longer gas depletion timescales. We find evidence for environmental quenching of satellites, but central galaxies in the TZ defy simple quenching pa…
Detecting galaxies when their star-formation is being quenched is crucial to understand the mechanisms driving their evolution. We identify for the first time a sample of quenching galaxies selected just after the interruption of their star formation by exploiting the [O III]5007/Halpha ratio and searching for galaxies with undetected [O III]. Using a sample of ~174000 star-forming galaxies extracted from the SDSS-DR8 at 0.04 < z < 0.21,we identify the ~300 quenching galaxy best candidates with low [O III]/Halpha, out of ~26000 galaxies without [O III] emission. They have masses between 10^9.7…
We present predictions for the quenching of star formation in satellite galaxies of the Local Group from a suite of 30 cosmological zoom simulations of Milky Way-like host galaxies. The Auriga simulations resolve satellites down to the luminosity of the classical dwarf spheroidal galaxies of the Milky Way. We find strong mass-dependent and distance-dependent quenching signals, where dwarf systems beyond 600 kpc are only strongly quenched below a stellar mass of $10^7$ M$_\odot$. Ram pressure stripping appears to be the dominant quenching mechanism and 50% of quenched systems cease star formati…
Using a novel approach, we study the quenching and bursting of galaxies as a function of stellar mass ($M_{*}$), local environment ($Σ$), and specific star-formation rate (sSFR) using a large spectroscopic sample of $\sim$ 123,000 $GALEX$/SDSS and $\sim$ 420 $GALEX$/COSMOS/LEGA-C galaxies to $z$ $\sim$ 1. We show that out to $z$ $\sim$ 1 and at fixed sSFR and local density, on average, less massive galaxies are quenching, whereas more massive systems are bursting, with a quenching/bursting transition at log($M_{*}$/$M_{\odot}$) $\sim$ 10.5-11 and likely a short quenching/bursting timescale ($\…
The phenomenological study of evolving galaxy populations has shown that star forming galaxies can be quenched by two distinct processes: mass quenching and environment quenching (Peng et al. 2010). To explore the mass quenching process in local galaxies, we study the massive central disk galaxies with stellar mass above the Schechter characteristic mass. In Zhang et al. (2019), we showed that during the quenching of the massive central disk galaxies as their star formation rate (SFR) decreases, their molecular gas mass and star formation efficiency drop rapidly, but their HI gas mass remains …
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 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 …
Understanding how and why star formation turns off in massive galaxies is a major challenge for studies of galaxy evolution. Many theoretical explanations have been proposed, but a definitive consensus is yet to be reached.
We investigate the timescale with which the IR luminosity decreases after a complete and rapid quenching of star formation using observations of local and high-redshift galaxies. From SED modelling, we derive the time since quenching of a subsample of 14 galaxies from the Herschel Reference Survey suffering from ram-pressure stripping due to the environment of the Virgo cluster and of a subsample of 7 rapidly quenched COSMOS galaxies selected through a state-of-the-art statistical method already tested on the determination of galaxies' star formation history. Three out of the 7 COSMOS galaxies…
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…
We explore the quenching of low-mass galaxies (10^4 < Mstar < 10^8 Msun) as a function of lookback time using the star formation histories (SFHs) of 38 Local Group dwarf galaxies. The SFHs were derived from analyzing color-magnitude diagrams of resolved stellar populations in archival Hubble Space Telescope/Wide Field Planetary Camera 2 imaging. We find: (1) Lower mass galaxies quench earlier than higher mass galaxies; (2) Inside of virial radius there is no correlation between a satellite's current proximity to a massive host and its quenching epoch; (3) There are hints of systematic differen…
Understanding when, how and where star formation ceased (quenching) within galaxies is still a critical subject in galaxy evolution studies. Taking advantage of the new methodology developed by Quai et al. (2018) to select recently quenched galaxies, we explored the spatial information provided by IFU data to get critical insights on this process. In particular, we analyse 10 SDSS-IV MaNGA galaxies that show regions with low [O III]/Hα compatible with a recent quenching of the star formation. We compare the properties of these 10 galaxies with those of a control sample of 8 MaNGA galaxies with…
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…
Recent quasar surveys have revealed that supermassive black holes (SMBHs) rarely exceed a mass of $M_{\rm BH} \sim {\rm a~few}\times10^{10}~M_{\odot}$ during the entire cosmic history. It has been argued that quenching of the BH growth is caused by a transition of a nuclear accretion disk into an advection dominated accretion flow, with which strong outflows and/or jets are likely to be associated. We investigate a relation between the maximum mass of SMBHs and the radio-loudness of quasars with a well-defined sample of $\sim 10^5$ quasars at a redshift range of $0<z<2$, obtained from the Sloa…
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…
A rare population of massive disk galaxies have been found to invade the red sequence dominated by early-type galaxies. These red/quenched massive disk galaxies have recently gained great interest into their formation and origins. The usually proposed quenching mechanisms, such as bar quenching and environment quenching, seem not suitable for those bulge-less quenched disks in low-density environment. In this paper, we use the IllustrisTNG-300 simulation to investigate the formation of massive quenched central disk galaxies. It is found that these galaxies contain less gas and harbor giant sup…
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 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…
We study the quenching of galaxies in different environments and its evolution in the redshift range $0.43 \leq z \leq 0.89$. For this purpose, we identify galaxies inhabiting filaments, the isotropic infall region of groups, the field, and groups in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We classify galaxies as quenched (passive), through their $NUV-r$ versus $r-K$ colours. We study the fraction of quenched galaxies ($F_{r}$) as a function of stellar mass and environment at two redshift intervals. Our results confirm that stellar mass is the dominant factor determining galax…
The timescales for galaxy quenching offer clues to its underlying physical drivers. We investigate central galaxy quenching timescales in the IllustrisTNG 100-1 simulation, their evolution over time, and the pre-quenching properties of galaxies that predict their quenching timescales. Defining quenching duration $τ_q$ as the time between crossing sSFR thresholds, we find that $\sim$40% of galaxies quench rapidly with $τ_q<$1 Gyr, but a substantial tail of galaxies can take up to 10 Gyr to quench. Furthermore, 29% of galaxies that left the star forming main sequence (SFMS) more than 2 Gyr ago n…
Despite decreasing cosmic star formation rate density over the last 10 Gyr, the stellar mass ($M_{*}$) buildups in galaxies were still progressing during this epoch. About 50\% of the current $M_{*}$ density in the universe was built over the last $\sim 8.7$ Gyr. In this research, we investigated the stellar mass buildup and quenching of spatially resolved regions within massive disk galaxies over the last 10 Gyr. We apply the spectral energy distribution (SED) fitting method to SEDs of sub-galactic regions in galaxies to derive the spatially resolved distributions of SFR and $M_{*}$ in the ga…
Previous findings show that the existence of dense cores or bulges is the prerequisite for quenching a galaxy, leading to a proposed two-step quenching scenario: compaction and quenching. In this scenario, galaxies first grow their cores to a stellar mass surface density threshold and subsequently quenching occurs, suggesting that galaxies evolve from extended star-forming galaxies (eSFGs), through compact star-forming galaxies (cSFGs), to quenched population. In this work, we aim at examining the possible evolutionary link between eSFGs and cSFGs by identifying the trends in star formation ra…
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…
Star-forming galaxies can in principle be transformed into passive systems by a multitude of processes that quench star formation, such as the halting of gas accretion (starvation) or the rapid removal of gas in AGN-driven outflows. However, it remains unclear which processes are the most significant, primary drivers of the SF-passive bimodality. We address this key issue in galaxy evolution by studying the chemical properties of 80,000 local galaxies in SDSS DR7. In order to distinguish between different quenching mechanisms, we analyse the stellar metallicities of star-forming, green valley …
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 investigate the stellar populations for a sample of 24 quiescent galaxies at 1.5 < z < 2.5 using deep rest-frame optical spectra obtained with Keck MOSFIRE. By fitting templates simultaneously to the spectroscopic and photometric data, and exploring a variety of star formation histories, we obtain robust measurements of median stellar ages and residual levels of star formation. After subtracting the stellar templates, the stacked spectrum reveals the Halpha and [NII] emission lines, providing an upper limit on the ongoing star formation rate of 0.9 +/- 0.1 Msun/yr. By combining the MOSFIRE …
We describe the SQuIGGLE survey of intermediate-redshift post-starburst galaxies. We leverage the large sky coverage of the SDSS to select ~1300 recently-quenched galaxies at 0.5<z<~0.9 based on their unique spectral shapes. These bright, intermediate-redshift galaxies are ideal laboratories to study the physics responsible for the rapid quenching of star formation: they are distant enough to be useful analogs for high-redshift quenching galaxies, but low enough redshift that multi-wavelength follow-up observations are feasible with modest telescope investments. We use the Prospector code to i…
We compile a sample of SDSS galaxy clusters with high-quality Chandra X-ray data to directly study the influence of the dense intra-cluster medium (ICM) on the quenching of satellite galaxies. We study the quenched fractions of satellite galaxies as a function of ICM density for low- ($10^9 \lesssim M_\star \lesssim 10^{10}\,\mathrm{M_\odot}$), intermediate- ($10^{10} \lesssim M_\star \lesssim 10^{10.5}\,\mathrm{M_\odot}$), and high-mass ($M_\star \gtrsim 10^{10.5}\,\mathrm{M_\odot}$) satellite galaxies with $>\!3000$ satellite galaxies across 24 low-redshift ($z < 0.1$) clusters. For low-mass…
Many disc galaxies in clusters have been found with bulges of similar age or younger than their surrounding discs, at odds with field galaxies of similar morphology and their expected inside-out formation. We use the EAGLE simulations to test potential origins for this difference in field and cluster galaxies. We find, in agreement with observations, that on average disc-dominated field galaxies in the simulations have older inner regions, while similar galaxies in groups and clusters have similarly aged or younger inner regions. This environmental difference is a result of outside-in quenchin…
The ALMaQUEST Survey XVII: Unveiling Multiple Quenching Pathways in Green Valley Galaxies via Molecular Gas and Quenching Timescale Analyses
Institute of Astronomy & Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；Graduate Institute of Astrophysics and Department of Physics, National Taiwan University（国立台湾大学天体物理研究所暨物理系）；Argelander-Institut für Astronomie, Universität Bonn（波恩大学阿尔兰德天文学研究所）；Stocker AstroScience Center, Dept. of Physics, Florida International University（佛罗里达国际大学斯托克天体科学中心物理系）；Department of Physics, Tamkang University（淡江大学物理系）；Department of Physics & Astronomy, University of Victoria（维多利亚大学物理与天文系）；Space Telescope Science Institute（太空望远镜科学研究所）；William H. Miller III Department of Physics and Astronomy, Johns Hopkins University（约翰斯·霍普金斯大学威廉·H·米勒三世物理与天文系）；Instituto de Astronomía, Universidad Nacional Autónoma de México（墨西哥国立自治大学天文学研究所）
Intermediate-mass black holes (BHs) in local dwarf galaxies are considered the relics of the early seed BHs. However, their growth might have been impacted by galaxy mergers and BH feedback so that they cannot be treated as tracers of the early seed BH population.
The ngVLA will facilitate deep surveys capable of detecting the faint and compact signatures of accreting supermassive black holes (SMBHs) with masses below one million solar-masses hosted by low-mass ($< 10^9$ solar-masses) galaxies. This will provide important new insights on both the origins of supermassive black holes and the possible impact of active galactic nucleus-driven feedback in a currently unexplored mass regime.
The so-called star-forming main sequence of galaxies is the apparent tight relationship between the star formation rate and stellar mass of a galaxy. Previous studies exclude galaxies which are not strictly 'star forming' from the main sequence, because they do not lie on the same tight relation. Using local galaxies in the Sloan Digital Sky Survey we have classified galaxies according to their emission line ratios, and studied their location on the star formation rate - stellar mass plane. We find that galaxies form a sequence from the `blue cloud' galaxies which are actively forming stars, t…
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…
Satellite quenching and morphological transformation of galaxies in groups and clusters
Department of Physics and Astronomy, McMaster University（麦克马斯特大学物理与天文学系）；NAT-Universidade Cidade de São Paulo（圣保罗城市大学）；School of Physics and Astronomy, University of Nottingham（诺丁汉大学物理与天文学院）
