Multiphase Gas and Star Formation in Cluster Cores

Abstract

We will present new Hubble Space Telescope COS and STIS spectroscopy of the central knots in the Brightest Cluster Galaxy in the CLASH cluster RXJ1532.9+3021. X-ray observations show this cluster hosts a radio AGN that has excavated large holes in the X-ray intracluster medium. The X-ray gas in the core of this cluster is extremely luminous. Although the star formation visible in the cluster is higher than that of many starburst galaxies (> 100 solar masses per year, estimated from FIR and UV -based SFRs), the AGN appears to preventing a far higher rate of star formation. We place very strong limits on the rate of gas cooling from intermediate gas temperatures (~1 million K) using UV spectroscopy. The UV spectra from the center of this BCG bear a strong resemblance to that of the most extreme Lyman Break galaxies at z~3, including significant UV continuum and absorption line features from recently formed hot stars and Lyman alpha emission and Lyman beta absorption consistent with winds driven by hot stars. We will discuss the implications of the state of this system in context with the handful of other active BCGs that have spectroscopy at similar rest wavelengths.