The growth of brightest cluster galaxies and intracluster light over the past 10 billion years

Abstract

We constrain the evolution of the brightest cluster galaxy plus intracluster light (BCG+ICL) using an ensemble of 42 galaxy groups and clusters that span redshifts of z = 0.05 − 1.75 and masses of M 500,c = 2 × 10 13 − 10 15 M . Specifically, we measure the relationship between the BCG+ICL stellar mass M and M 500,c at projected radii 10 < r < 100 kpc for three different epochs. At intermediate redshift (z = 0.40), where we have the best data, we find M ∝M 500,c 0.48±0.06 . Fixing the exponent of this power law for all redshifts, we constrain the normalization of this relation to be 2.08 ± 0.21 times higher atz = 0.40 than at high redshift (z = 1.55). We find no change in the relation from intermediate to low redshift (z = 0.10). In other words, for fixed M 500,c , M at 10 < r < 100 kpc increases fromz = 1.55 toz = 0.40 and not significantly thereafter. Theoretical models predict that the physical mass growth of the cluster from z = 1.5 to z = 0 within r 500,c is 1.4×, excluding evolution due to definition of r 500,c . We find that M within the central 100 kpc increases by ∼ 3.8× over the same period. Thus, the growth of M in this central region is more than a factor of two greater than the physical mass growth of the cluster as a whole. Furthermore, the concentration of the BCG+ICL stellar mass, defined by the ratio of stellar mass within 10 kpc to the total stellar mass within 100 kpc, decreases with increasing M 500,c at all z. We interpret this result as evidence for inside-out growth of the BCG+ICL over the past ten Gyrs, with stellar mass assembly occuring at larger radii at later times.

Physical properties of brightest cluster galaxies up to redshift 1.80 based on HST data

“…We also exclude all BCGs at redshift z > 0.9 on the blue histogram. studies found in the literature based on HST images, such as Bai et al (2014), DeMaio et al (2019. We studied the luminosity profiles of these galaxies and how they evolve as a function of redshift.…”

“…4). Postman et al (2012a), Bai et al (2014), Donahue et al (2015), West et al (2017), DeMaio et al (2019, Durret et al (2019), andSazonova et al (2020). We also add five more distant clusters at z ≥ 0.8, as well as the cluster Abell 2813 at z = 0.29.…”

“…Cerulo et al (2019) studied a sample 74 275 BCGs from the SDSS in the redshift range 0.05 ≤ z ≤ 0.35, and is not represented in this figure for better legibility. Most large studies, especially those with HST data (represented in red), were done exclusively on local BCGs (z ≤ 0.1) (Lauer et al 2014;Cerulo et al 2019), while farther clusters and BCGs were limited to relatively small samples (N ≤ 45) (Bai et al 2014;DeMaio et al 2019;Durret et al 2019) and/or used ground-based data (represented in black). Our sample contains more clusters and BCGs at high redshifts (z ≥ 0.7) than that of Lidman et al (2012) (73 and 33, respectively).…”

“…To avoid handling such heavy files, we first cropped these images, defined the new center on the cluster coordinates found in NED, and created a new image that was 1.2 Mpc wide. Linear scales (arcsec Mpc −1 ) were determined from the cluster redshifts in the literature (from Jee et al 2011;Postman et al 2012a;Bai et al 2014;Donahue et al 2015;West et al 2017;DeMaio et al 2019;Durret et al 2019;Sazonova et al 2020, or were found in NED for the five other clusters we added). Cluster information can be found in Table 1.…”

Is diffuse intracluster light a good tracer of the galaxy cluster matter distribution?

“…Additional evidence for such a connection between diffuse intracluster light and the underlying cluster dark matter distribution can be found in a few other observation-based studies. Many have noticed a correlation between cluster mass (including dark matter mass) and total diffuse light luminosity or stellar mass especially at large radius (e.g., Zibetti et al 2005;Kluge et al 2020;DeMaio et al 2020;Huang et al 2018b,a). Moreover, Zhang et al (2019b, hereafter Z19) discovered that the ratio between diffuse light surface brightness and a weak-lensing measurement-based cluster mass-density model appears to be flat with a cluster radius outside 100 kpc, and that diffuse intracluster light radial profiles are "self-similar", i.e., independent of cluster mass after scaling by cluster radius.…”