Size growth of red-sequence early-type galaxies in clusters in the last 10 Gyr

Abstract

We carried out a photometric and structural analysis in the rest-frame V band of a mass-selected (log M/M > 10.7) sample of red-sequence galaxies in 14 galaxy clusters, 6 of which are at z > 1.45, namely JKCS041, IDCS J1426.5+3508, SpARCS104922.6+564032.5, SpARCSJ021524-034331, XDCPJ0044.0-2033, and SPT-CLJ2040-4451. To this end, we reduced/analyzed about 300 orbits of multicolor images taken with the Advanced Camera for Survey and the Wide Field Camera 3 on the Hubble Space Telescope. We uniformly morphologically classified galaxies from z = 0.023 to z = 1.803, and we homogeneously derived sizes (effective radii) for the entire sample. Furthermore, our size derivation allows, and therefore is not biased by, the presence of the usual variety of morphological structures seen in early-type galaxies, such as bulges, bars, disks, isophote twists, and ellipiticy gradients. By using such a mass-selected sample, composed of 244 red-sequence early-type galaxies, we find that the log of the galaxy size at a fixed stellar mass, log M/M = 11, has increased with time at a rate of 0.023 ± 0.002 dex per Gyr over the last 10 Gyr, in marked contrast with the threefold increase found in the literature for galaxies in the general field over the same period. This suggests, at face value, that secular processes should be excluded as the primary drivers of size evolution because we observed an environmental dependent size growth. Using spectroscopic ages of Coma early-type galaxies we also find that recently quenched early-type galaxies are a numerically minor population not different enough in size to alter the mean size at a given mass, which implies that the progenitor bias is minor, i.e., that the size evolution measured by selecting galaxies at the redshift of observation is indistinguishable from the one that compares ancestors and descendents.

Bimodal morphologies of massive galaxies at the core of a protocluster at z = 3.09 and the strong size growth of a brightest cluster galaxy

“…It is reported that QGs in protoclusters have sizes larger than those in general fields at z < 2, implying accelerated size growths of them in overdense regions, possibly by enhanced merger rates (Zirm, Toft, & Tanaka 2012;Cooper et al 2012;Papovich et al 2012;Lotz et al 2013;Newman et al 2014;Andreon, Dong, & Raichoor 2016). At first, our results challenge the reliability of past studies arguing compact morphologies of QGs at high redshift without NIR spectroscopic follow-ups.…”

“…Discovery of a massive compact elliptical, Az14-K15c, in such a proto-BCG group supports the two-phase formation scenario of giant elliptical galaxies that massive compact ellipticals formed at once and they evolve in sizes and stellar masses by series of mergers (e.g., Oser et al 2010), which has also been supported by many observational studies (e.g., van Dokkum et al 2010;Morishita et al 2015;Zirm, Toft, & Tanaka 2012;Cooper et al 2012;Papovich et al 2012;Lotz et al 2013;Newman et al 2014;Andreon, Dong, & Raichoor 2016).…”

“…Protoclusters are suitable targets to study progenitors of galaxies dominating rich cluster cores today. The strong size growths of massive ETGs is supported from many studies of QGs in the protoclusters at z < 2 (Zirm, Toft, & Tanaka 2012;Cooper et al 2012;Papovich et al 2012;Lotz et al 2013;Newman et al 2014;Andreon, Dong, & Raichoor 2016). But it is not still unclear how their evolutions relate to environments at earlier time.…”

The Delay Times of Type Ia Supernova

“…This method assumes that the galaxies in the sample formed at nearly the same redshift (z ∼ 3-4, e.g. Andreon et al 2016), and therefore only the late time DTD is probed (t 3.2 Gyr, Friedmann & Maoz 2018). This method also assumes that the observed supernovae did not originate from residual young populations (Schawinski 2009).…”

Disky Elliptical Galaxies and the Allegedly Over-Massive Black Hole in the Compact Massive “Es” Galaxy NGC 1271

“…Daddi et al 2005;Toft et al 2007;Trujillo et al 2007;Damjanov et al 2009Damjanov et al , 2014Weinzirl et al 2011;Prieto et al 2013;van Dokkum et al 2008van Dokkum et al , 2015Carollo et al 2013;Zahid et al 2016;Andreon et al 2016). In mid-2011 Graham pointed out that these galaxies have the same physical properties as the spheroidal component of some local lenticular galaxies (Graham 2013).…”