scholarly journals The GOGREEN survey: transition galaxies and the evolution of environmental quenching

2021 ◽  
Vol 508 (1) ◽  
pp. 157-174
Author(s):  
Karen McNab ◽  
Michael L Balogh ◽  
Remco F J van der Burg ◽  
Anya Forestell ◽  
Kristi Webb ◽  
...  

ABSTRACT We measure the rate of environmentally driven star formation quenching in galaxies at z ∼ 1, using eleven massive ($M\approx 2\times 10^{14}\, \mathrm{M}_\odot$) 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 a function of stellar mass and environment. For high-stellar mass galaxies (log M/M⊙ > 10.5) we do not find any significant excess of transition galaxies in clusters, relative to a comparison field sample at the same redshift. It is likely that such galaxies were quenched prior to their accretion in the cluster, in group, filament, or protocluster environments. For lower stellar mass galaxies (9.5 < log M/M⊙ < 10.5) there is a small but significant excess of transition galaxies in clusters, accounting for an additional ∼5–10 per cent of the population compared with the field. We show that our data are consistent with a scenario in which 20–30 per cent of low-mass, star-forming galaxies in clusters are environmentally quenched every Gyr, and that this rate slowly declines from z = 1 to z = 0. While environmental quenching of these galaxies may include a long delay time during which star formation declines slowly, in most cases this must end with a rapid (τ < 1 Gyr) decline in star formation rate.

2016 ◽  
Vol 11 (S321) ◽  
pp. 327-329 ◽  
Author(s):  
Sandro Tacchella ◽  
C. Marcella Carollo ◽  
Avishai Dekel ◽  
Natascha Förster Schreiber ◽  
Alvio Renzini ◽  
...  

AbstractIn order to constrain – and understand – the growth of galaxies, we present a sample of ~ 30 galaxies at z ~ 2 with resolved distribution of stellar mass, star-formation rate, and dust attenuation on scales of ~ 1 kpc. We find that low- and intermediate-mass galaxies grow self-similarly, doubling their stellar mass in the centers and outskirts with the same pace. More massive galaxies (~ 1011 M⊙) have a reduced star-formation activity in their center: they grow mostly in the outskirts (inside-out quenching / formation). Similar trends are find in cosmological zoom-in simulations, highlighting that high stellar mass densities are formed in a gas-rich compaction phase. This nuclear ‘starburst’ phase is followed by a suppressed star-formation activity in the center, resulting in growth of the outskirts. All in all, we put forward that we witness at z ~ 2 the dissipative formation of z = 0 M* early-type galaxies.


2019 ◽  
Vol 631 ◽  
pp. A156 ◽  
Author(s):  
L. A. Díaz-García ◽  
A. J. Cenarro ◽  
C. López-Sanjuan ◽  
I. Ferreras ◽  
M. Cerviño ◽  
...  

Aims. Our aim is to determine the distribution of stellar population parameters (extinction, age, metallicity, and star formation rates) of quiescent galaxies within the rest-frame stellar mass–colour diagrams and UVJ colour–colour diagrams corrected for extinction up to z ∼ 1. These novel diagrams reduce the contamination in samples of quiescent galaxies owing to dust-reddened galaxies, and they provide useful constraints on stellar population parameters only using rest-frame colours and/or stellar mass. Methods. We set constraints on the stellar population parameters of quiescent galaxies combining the ALHAMBRA multi-filter photo-spectra with our fitting code for spectral energy distribution, MUlti-Filter FITting (MUFFIT), making use of composite stellar population models based on two independent sets of simple stellar population (SSP) models. The extinction obtained by MUFFIT allowed us to remove dusty star-forming (DSF) galaxies from the sample of red UVJ galaxies. The distributions of stellar population parameters across these rest-frame diagrams are revealed after the dust correction and are fitted by LOESS, a bi-dimensional and locally weighted regression method, to reduce uncertainty effects. Results. Quiescent galaxy samples defined via classical UVJ diagrams are typically contaminated by a ∼20% fraction of DSF galaxies. A significant part of the galaxies in the green valley are actually obscured star-forming galaxies (∼30–65%). Consequently, the transition of galaxies from the blue cloud to the red sequence, and hence the related mechanisms for quenching, seems to be much more efficient and faster than previously reported. The rest-frame stellar mass–colour and UVJ colour–colour diagrams are useful for constraining the age, metallicity, extinction, and star formation rate of quiescent galaxies by only their redshift, rest-frame colours, and/or stellar mass. Dust correction plays an important role in understanding how quiescent galaxies are distributed in these diagrams and is key to performing a pure selection of quiescent galaxies via intrinsic colours.


2018 ◽  
Vol 14 (S345) ◽  
pp. 27-33
Author(s):  
Josefa E. Großschedl ◽  
João Alves ◽  
Stefan Meingast ◽  
Birgit Hasenberger

AbstractThe giant molecular cloud Orion A is the closest massive star-forming region to earth (d ∼ 400 pc). It contains the rich Orion Nebula Cluster (ONC) in the North, and low-mass star-forming regions (L1641, L1647) to the South. To get a better understanding of the differences in star formation activity, we perform an analysis of the gas mass distribution and star formation rate across the cloud. We find that the gas is roughly uniformly distributed, while, oddly, the ONC region produced about a factor of ten more stars compared to the rest of the cloud. For a better interpretation of this phenomenon, we use Gaia DR2 parallaxes, to analyse distances of young stellar objects, using them as proxy for cloud distances. We find that the ONC region indeed lies at about 400 pc while the low-mass star-forming parts are inclined about 70∘ from the plane of the sky reaching until ∼470 pc. With this we estimate that Orion A is an about 90 pc long filamentary cloud (about twice as long as previously assumed), with its “Head” (the ONC region) being “bent” and oriented towards the galactic mid-plane. This striking new view allows us to perform a more robust analysis of this important star-forming region in the future.


2019 ◽  
Vol 492 (1) ◽  
pp. 1492-1512
Author(s):  
S Gillman ◽  
A L Tiley ◽  
A M Swinbank ◽  
C M Harrison ◽  
Ian Smail ◽  
...  

ABSTRACT We present an analysis of the gas dynamics of star-forming galaxies at z ∼ 1.5 using data from the KMOS Galaxy Evolution Survey. We quantify the morphology of the galaxies using HSTcandels imaging parametrically and non-parametrically. We combine the H α dynamics from KMOS with the high-resolution imaging to derive the relation between stellar mass (M*) and stellar specific angular momentum (j*). We show that high-redshift star-forming galaxies at z ∼ 1.5 follow a power-law trend in specific stellar angular momentum with stellar mass similar to that of local late-type galaxies of the form j*  ∝  M$_*^{0.53\, \pm \, 0.10}$. The highest specific angular momentum galaxies are mostly disc-like, although generally both peculiar morphologies and disc-like systems are found across the sequence of specific angular momentum at a fixed stellar mass. We explore the scatter within the j* – M* plane and its correlation with both the integrated dynamical properties of a galaxy (e.g. velocity dispersion, Toomre Qg, H α star formation rate surface density ΣSFR) and its parametrized rest-frame UV / optical morphology (e.g. Sérsic index, bulge to total ratio, clumpiness, asymmetry, and concentration). We establish that the position in the j* – M* plane is strongly correlated with the star-formation surface density and the clumpiness of the stellar light distribution. Galaxies with peculiar rest-frame UV / optical morphologies have comparable specific angular momentum to disc- dominated galaxies of the same stellar mass, but are clumpier and have higher star formation rate surface densities. We propose that the peculiar morphologies in high-redshift systems are driven by higher star formation rate surface densities and higher gas fractions leading to a more clumpy interstellar medium.


2021 ◽  
Vol 502 (1) ◽  
pp. 1051-1069
Author(s):  
Mohammadreza Ayromlou ◽  
Dylan Nelson ◽  
Robert M Yates ◽  
Guinevere Kauffmann ◽  
Malin Renneby ◽  
...  

ABSTRACT We perform a comparison, object by object and statistically, between the Munich semi-analytical model, L-GALAXIES, and the IllustrisTNG hydrodynamical simulations. By running L-GALAXIES on the IllustrisTNG dark matter-only merger trees, we identify the same galaxies in the two models. This allows us to compare the stellar mass, star formation rate, and gas content of galaxies, as well as the baryonic content of subhaloes and haloes in the two models. We find that both the stellar mass functions and the stellar masses of individual galaxies agree to better than ${\sim} 0.2\,$dex. On the other hand, specific star formation rates and gas contents can differ more substantially. At z = 0, the transition between low-mass star-forming galaxies and high-mass quenched galaxies occurs at a stellar mass scale ${\sim} 0.5\,$dex lower in IllustrisTNG than that in L-GALAXIES. IllustrisTNG also produces substantially more quenched galaxies at higher redshifts. Both models predict a halo baryon fraction close to the cosmic value for clusters, but IllustrisTNG predicts lower baryon fractions in group environments. These differences are primarily due to differences in modelling feedback from stars and supermassive black holes. The gas content and star formation rates of galaxies in and around clusters and groups differ substantially, with IllustrisTNG satellites less star forming and less gas rich. We show that environmental processes such as ram-pressure stripping are stronger and operate to larger distances and for a broader host mass range in IllustrisTNG. We suggest that the treatment of galaxy evolution in the semi-analytic model needs to be improved by prescriptions that capture local environmental effects more accurately.


2020 ◽  
Vol 500 (2) ◽  
pp. 2036-2048
Author(s):  
Antonios Katsianis ◽  
Haojie Xu ◽  
Xiaohu Yang ◽  
Yu Luo ◽  
Weiguang Cui ◽  
...  

ABSTRACT We present the eddington bias corrected specific star formation rate function (sSFRF) at different stellar mass scales from a sub-sample of the Sloan Digital Sky Survey Data Release DR7 (SDSS), which is considered complete both in terms of stellar mass (M⋆) and star formation rate (SFR). The above enable us to study qualitatively and quantitatively quenching, the distribution of passive/star-forming galaxies and perform comparisons with the predictions from state-of-the-art cosmological models, within the same M⋆ and SFR limits. We find that at the low-mass end (${M_{\star }} = 10^{9.5}\!-\!10^{10} \, {\rm M_{\odot }}$) the sSFRF is mostly dominated by star-forming objects. However, moving to the two more massive bins (${M_{\star }} = 10^{10}\!-\!10^{10.5} \, {\rm M_{\odot }}$ and ${M_{\star }} = 10^{10.5}\!-\!10^{11} \, {\rm M_{\odot }}$) a bi-modality with two peaks emerges. One peak represents the star-forming population, while the other describes a rising passive population. The bi-modal form of the sSFRFs is not reproduced by a range of cosmological simulations (e.g. Illustris, EAGLE, Mufasa, and IllustrisTNG) which instead generate mostly the star-forming population, while a bi-modality emerges in others (e.g. L-Galaxies, Shark, and Simba). Our findings reflect the need for the employed quenching schemes in state-of-the-art models to be reconsidered, involving prescriptions that allow ‘quenched galaxies’ to retain a small level of SF activity (sSFR = ${\rm 10^{-11} \, }$–${\rm 10^{-12} \, {\rm yr^{-1}}}$) and generate an adequate passive population/bi-modality even at intermediate masses (${M_{\star }} = 10^{10}\!-\!10^{10.5} \, {\rm M_{\odot }}$).


2010 ◽  
Vol 6 (S270) ◽  
pp. 503-506
Author(s):  
Pedro Colín ◽  
Vladimir Avila-Reese ◽  
Octavio Valenzuela

AbstractCosmological Adaptive Mesh Refinement simulations are used to study the specific star formation rate (sSFR=SSF/Ms) history and the stellar mass fraction, fs=Ms/MT, of small galaxies, total masses MT between few × 1010 M⊙ to few ×1011 M⊙. Our results are compared with recent observational inferences that show the so-called “downsizing in sSFR” phenomenon: the less massive the galaxy, the higher on average is its sSFR, a trend seen at least since z ~ 1. The simulations are not able to reproduce this phenomenon, in particular the high inferred values of sSFR, as well as the low values of fs constrained from observations. The effects of resolution and sub-grid physics on the SFR and fs of galaxies are discussed.


Author(s):  
P Bonfini ◽  
A Zezas ◽  
M L N Ashby ◽  
S P Willner ◽  
A Maragkoudakis ◽  
...  

Abstract We constrain the mass distribution in nearby, star-forming galaxies with the Star Formation Reference Survey (SFRS), a galaxy sample constructed to be representative of all known combinations of star formation rate (SFR), dust temperature, and specific star formation rate (sSFR) that exist in the Local Universe. An innovative two-dimensional bulge/disk decomposition of the 2MASS/Ks-band images of the SFRS galaxies yields global luminosity and stellar mass functions, along with separate mass functions for their bulges and disks. These accurate mass functions cover the full range from dwarf galaxies to large spirals, and are representative of star-forming galaxies selected based on their infra-red luminosity, unbiased by AGN content and environment. We measure an integrated luminosity density j = 1.72 ± 0.93 × 109 L⊙  h−1 Mpc−3 and a total stellar mass density ρM = 4.61 ± 2.40 × 108 M⊙  h−1 Mpc−3. While the stellar mass of the average star-forming galaxy is equally distributed between its sub-components, disks globally dominate the mass density budget by a ratio 4:1 with respect to bulges. In particular, our functions suggest that recent star formation happened primarily in massive systems, where they have yielded a disk stellar mass density larger than that of bulges by more than 1 dex. Our results constitute a reference benchmark for models addressing the assembly of stellar mass on the bulges and disks of local (z = 0) star-forming galaxies.


2010 ◽  
Vol 6 (S270) ◽  
pp. 103-106
Author(s):  
R. Rao ◽  
J.-M. Girart ◽  
D. P. Marrone

AbstractThere have been a number of theoretical and computational models which state that magnetic fields play an important role in the process of star formation. Competing theories instead postulate that it is turbulence which is dominant and magnetic fields are weak. The recent installation of a polarimetry system at the Submillimeter Array (SMA) has enabled us to conduct observations that could potentially distinguish between the two theories. Some of the nearby low mass star forming regions show hour-glass shaped magnetic field structures that are consistent with theoretical models in which the magnetic field plays a dominant role. However, there are other similar regions where no significant polarization is detected. Future polarimetry observations made by the Submillimeter Array should be able to increase the sample of observed regions. These measurements will allow us to address observationally the important question of the role of magnetic fields and/or turbulence in the process of star formation.


2014 ◽  
Vol 11 (S308) ◽  
pp. 475-476
Author(s):  
Jaan Vennik

AbstractWe studied the variation of stellar mass and various star-formation characteristics of satellite galaxies in a volume limited sample of nearby groups as a function of their group-centric distance and of their relative line-of-sight velocity in the group rest frame. We found clear radial dependencies, e.g. massive, red and passive satellites being distributed predominantly near the center of composite group. We also found some evidence of velocity modulation of star-forming properties of satellite galaxies near the group virial radius. We conclude that using kinematical data, it should be feasible to separate dynamical classes of bound, in-falling and 'backsplash' satellite galaxies.


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