Chemistry and Physics Faculty Articles

Document Type

Article

Publication Date

10-14-2008

Keywords

Galaxies: clusters: general, Galaxies: elliptical and lenticular, cD, Galaxies: evolution, Galaxies: interactions, Galaxies: spiral, Galaxies: structure

Publication Title

Astrophysical Journal Letters

ISSN

2041-8205

Volume

688

Issue/No.

1

First Page

L5

Last Page

L8

Peer Reviewed

1

Abstract

We study a unique protocluster of galaxies, the supergroup SG1120–1202. We quantify the degree to which morphological transformation of cluster galaxies occurs prior to cluster assembly in order to explain the observed early-type fractions in galaxy clusters at z = 0. SG1120–1202 at z ~ 0.37 is composed of four gravitationally bound groups that are expected to coalesce into a single cluster by z = 0. Using HST ACS observations, we compare the morphological fractions of the supergroup galaxies to those found in a range of environments. We find that the morphological fractions of early-type galaxies (~60%) and the ratio of S0 to elliptical galaxies (0.5) in SG1120–1202 are very similar to clusters at comparable redshift, consistent with preprocessing in the group environment playing the dominant role in establishing the observed early-type fraction in galaxy clusters.

Comments

©2008 The American Astronomical Society.

DOI

10.1086/593978

Find in your library

Share

COinS