Galaxy mass, cluster-centric distance and secular evolution: their role in the evolution of galaxies in clusters in the last 10 Gyr

Abstract

Context. Galaxy mass and environment are known to play a key role in galaxy evolution: studying galaxy colors as a function of redshift, galaxy mass, and environment offers a powerful diagnosis to disentangle the role of each. Aims. We study the simultaneous dependence of the fraction of blue galaxies f blue on secular evolution, environment, and galaxy mass with a well-controlled cluster sample. We are thus able to study the evolution and respective role of the cessation of star formation history (SFH) in clusters caused by galaxy mass ("mass quenching") or by environment ("environmental quenching"). Methods. We defined an homogenous X-ray selected cluster sample (25 clusters with 0 < z < 1 and one cluster at z ∼ 2.2), having similar masses and well-defined sizes. Using multicolor photometry and a large spectroscopic sample to calibrate photometric redshifts, we carefully estimated f blue for each cluster at different galaxy mass and cluster-centric distance bins. We then fitted the dependence of f blue on redshift (z), environment (r/r 200 ) and galaxy mass (M) with a simple model. Results. f blue increases with cluster-centric distance with a slope α = 1.2 +0.4 −0.3 , decreases with galaxy mass with a slope β = −3.8 +0.6 −0.5 , and increases with redshift with a slope γ = 3.3 +0.7 −0.6 . The data also require for the first time a differential evolution with galaxy mass of f blue with redshift, with lower mass galaxies evolving slower by a factor ζ = −3.9 +0.9 −1.1 . Conclusions. Our study shows that the processes responsible for the cessation of star formation in clusters are effective at all epochs (z < ∼ 2.2), and more effective in denser environments and for more massive galaxies. We found that the mass and environmental quenchings are separable, that environmental quenching does not change with epoch, and that mass quenching is a dynamical process, i.e. its evolutionary rate is mass-dependent. Our study extends the downsizing-like scenario, where the most massive galaxies have their properties set at a very high redshift, to the cluster environment and all galaxies. It illustrates the need to disentangle galaxy mass and cluster-centric distance to properly estimate the behavior of f blue in clusters.

Galaxy clusters and groups in the ALHAMBRA survey

“…Indeed, we find a significantly lower fraction of blue galaxies in z < 0.5 ALHAM-BRA groups consistent with more efficient environmental quenching in the local Universe (Peng et al 2010) and in agreement with other results on the blue fraction in more massive systems (Raichoor & Andreon 2012.…”

SPECTROSCOPIC CONFIRMATION OF THE RICHz= 1.80 GALAXY CLUSTER JKCS 041 USING THE WFC3 GRISM: ENVIRONMENTAL TRENDS IN THE AGES AND STRUCTURE OF QUIESCENT GALAXIES

“…This would move f Q in the lowest-mass bin only with the plotted 1σ uncertainty, resulting in a fraction that would still be elevated above the field. Using a photometric redshift selection and a statistical background subtraction, Raichoor & Andreon (2012) also estimated a high quiescent fraction f Q 85% (1σ limit) among massive galaxies (M * 10 11 M ) in the core of JKCS 041 (R < 0.5R 200 ), consistent with our spectroscopic sample.…”

“…We note that adopting the velocity window of ±2000(1 + z clus ) km s −1 advocated by Eisenhardt et al (2008) would remove only one galaxy from this sample. Among the several previously published estimates of the redshift of JKCS 041, the EAZY photometric redshifts with no corrections applied gave the true z clus (Raichoor & Andreon 2012). Spectra, images, and P (z) distributions for the 19 confirmed members are shown in Figure 5, and their coordinates and photometric properties are listed in Table 1.…”

“…Understanding the history of star formation quenching in different environments aids in disentangling the influence of these processes. Observationally, this is constrained by the evolution of the fraction of quenched galaxies and their star formation histories in clusters, groups, and the field (e.g., Finn et al 2010;Tran et al 2010;Quadri et al 2012;Muzzin et al 2012;Raichoor & Andreon 2012;Dressler et al 2013;Brodwin et al 2013;Bedregal et al 2013;Alberts et al 2014).…”

Do cluster properties affect the quenching rate?

“…We thus obtain 20 low-redshift clusters (MKW4, A1367, A1656, MKW8, A2199, A2634, A2052, A2147, A2063, A2657, A2589, MKW3S, A1795, A2065, ZwCl1215, A2029, A2255, A1650, A2142, A2244). We note that the seven less massive of those low-redshift clusters are included in the Raichoor & Andreon (2012a) sample.…”