Color Gradients in Early-Type Galaxies in Abell 2199

Abstract

We performed B and R band surface photometry for E/S0 galaxies in a nearby rich cluster ABELL 2199 to investigate their B − R color gradients (d(B − R)/d log r).Our aims are to study statistical properties of the color gradients and, by comparing them with those in less dense environments, to examine environmental dependence of color gradients in elliptical galaxies. We studied the distribution of the B − R color gradients in the cluster ellipticals and found that the mean value of the color gradients is −0.09 ± 0.04 mag/dex, which can be converted to a metallicity gradient (d log Z/d log r) of ∼ −0.3 ± 0.1. The gradient seems to be comparable to that expected by a recent monolithic collapse model. We further studied the relations between the B − R color gradients and global properties of the galaxies. Our data suggest that for the galaxies brighter than an R band magnitude of ∼ 15 mag, which is roughly equivalent to L * at the distance of the cluster, brighter galaxies tend to have steeper color gradients. Also, for the galaxies with effective radii larger than ∼ 3 ′′ , which nearly corresponds to L * considering the correlation between galaxy luminosity and effective radius for elliptical galaxies, the galaxies with larger effective radii seem to have steeper color gradients. These trends could appear if elliptical galaxies formed through the monolithic collapse scenario. On the contrary, it is found based on the published data that such trends are not clearly seen for elliptical galaxies in less dense environments, suggesting that elliptical galaxies in sparse environments formed by galaxy mergers, though the distribution of the color gradients is quite similar to that in the rich cluster. In other words, our data and those in the literature suggest that there is an environmental dependence in the relationship between color gradient and global properties of elliptical galaxies, while the distribution of the values of color gradients is nearly independent of galaxy environment. These results do not fully support the view that ellipticals in

Sizes, colour gradients and resolved stellar mass distributions for the massive cluster galaxies in XMMUJ2235-2557 atz= 1.39

“…Tamura & Ohta 2003;Wu et al 2005;Brough et al 2007;Reda et al 2007) as well as in recent simulations (e.g. Hirschmann et al 2015).…”

“…Saglia et al 2000;Tamura & Ohta 2003). For example, Kuntschner et al (2010) found a mean ∇ Z = −0.25 ± 0.11 and mean ∇ age = 0.02 ± 0.13 for galaxies with age > 8 Gyr.…”

“…Some works in clusters at z ∼ 0.4 (Saglia et al 2000) and local clusters (e.g. Tamura & Ohta 2003) showed however that the colour gradients may be preferentially produced by radial varia- tion in metallicity rather than age. The age gradients in local passive galaxies are consistent with 0 (or slightly positive), while the average metallicity gradient is found to be of ∇ Z ≈ −0.1 to −0.3 (see also Mehlert et al 2003;Wu et al 2005;La Barbera & de Carvalho 2009).…”

Robust automatic photometry of local galaxies from SDSS

“…Early type galaxies (e.g., Es and S0s) typically have almost flat and red profiles, common among the red and dead objects (Tamura & Ohta 2003;Wu et al 2005). Differently from the ETGs, irregular galaxies are characterized by an almost flat blue profile reflecting their lack of dust and their ongoing SF activity at all radii (Fig.…”

THE UV–OPTICAL COLOR GRADIENTS IN STAR-FORMING GALAXIES AT 0.5 < z < 1.5: ORIGINS AND LINK TO GALAXY ASSEMBLY

“…Although color gradients in nearby late-type galaxies (LTGs) appear to be dominated by the fact that on average their bulges are redder than their disks, LTGs show age, metallicity, and dust gradients because of the interplay among dust content, stellar feedback, bursts of star formation, and stellar migration (Gonzalez-Perez et al 2011). Earlier studies have claimed a weak correlation of color gradients with the physical properties of local galaxies (e.g., mass, luminosity, etc., Peletier et al 1990; Kobayashi & Arimoto 1999;Tamura & Ohta 2003). Recent studies based on larger and homogeneous samples of galaxies in SDSS have found that color gradients in local galaxies are closely correlated with their stellar masses, luminosities, sizes, and residual star formation (e.g., Suh et al 2010;Tortora et al 2010; Pan et al 2015).…”