A multi-wavelength analysis of Spitzer selected Coma Cluster galaxies: star formation rates and masses

TL;DR

This study analyzes star formation rates and galaxy masses in the Coma Cluster using multi-wavelength data, revealing that starbursts are mostly blue dwarfs located outside the cluster core.

Contribution

It provides a comprehensive multi-wavelength analysis of star formation and masses in Coma Cluster galaxies, confirming the lack of obscured star formation and characterizing starburst galaxy properties.

Findings

Starbursts are blue, dwarf galaxies with masses < 10^9 solar masses.

No evidence of additional obscured star formation component.

Lower fraction of starbursts in the cluster core.

Abstract

We present a thorough study of the specific star formation rates for MIPS 24um selected galaxies in the Coma cluster. We build galaxy spectral energy distributions using optical (u',g',r',i',z'), Near-infrared (J,H,Ks), and Mid to Far-infrared (IRAC and MIPS) photometry. New and archival spectra confirm 210 cluster members. Subsequently, the total infrared luminosity, galaxy stellar mass, and specific star formation rate for the members are determined by measuring best fit templates. Using an array of complementary diagnostics, we search for contaminating AGN, but find few. We compare obscured star formation rates to unobscured rates derived from extinction-corrected H-alpha emission line measurements. The agreement between these two values leads us to conclude that there is no evidence for an additionally obscured component. In our spectroscopic sample, complete to 80% for r' < 19.5, we find that all starbursts are blue and are dwarfs, having masses < 10^9 solar masses. Examining the location of these starbursts within the cluster, we confirm that there is a lower fraction in the cluster core.