Star formation properties of galaxy cluster A1767

TL;DR

This study investigates the stellar populations and star formation histories of galaxies in the galaxy cluster Abell 1767, revealing strong environmental effects on galaxy properties related to local density and stellar mass.

Contribution

It applies the STARLIGHT spectral synthesis code to a large, homogeneous SDSS sample to analyze environmental impacts on galaxy evolution within a relaxed galaxy cluster.

Findings

Massive galaxies in high-density regions have higher metallicities.

Star formation rates are suppressed in dense cluster cores.

Metallicity and SSFR correlate with stellar mass.

Abstract

Abell 1767 is a dynamically relaxed, cD cluster of galaxies with a redshift of 0.0703. Among 250 spectroscopically confirmed member galaxies within a projected radius of 2.5r_{200}, 243 galaxies (~ 97%) are spectroscopically covered by the Sloan Digital Sky Survey (SDSS). Based on this homogeneous spectral sample, the stellar evolutionary synthesis code, STARLIGHT, is applied to investigate the stellar populations and star formation histories (SFHs) of cluster galaxies. The star formation properties of galaxies, such as mean stellar ages, metallicities, stellar masses, and star formation rates (SFRs), are presented as the functions of local galaxy density. Strong environmental effect is found in the manner that massive galaxies in the high-density core region of cluster tend to have higher metallicities, longer mean stellar ages, and lower specific star formation rates (SSFRs), and their recent star formation activities have been remarkably suppressed. In addition, the correlations of the metallicity and SSFR with stellar mass are confirmed.