C IV absorbers tracing cool gas in dense galaxy group/cluster environments

Abstract

We present analysis on three intervening H I-C IV absorption systems tracing gas within galaxy group/cluster environments, identified in the HST/COS far-UV spectra of the background quasars PG 1148 + 549 (z_abs = 0.003 46), SBS 1122 + 594 (z_abs = 0.004 02), and RXJ 1230.8 + 0115 (z_abs = 0.005 74). The ionization models are consistent with the origin of metal lines and H I from a cool and diffuse photoionized gas phase with T ≲ 4 × 10⁴ K and n_{{H }} ≲ 5 × 10^{-4} cm^-3. The three absorbers have 89, 51, and 17 galaxies detected within 1 Mpc and |Δv| < 600 km s^-1. The RXJ 1230.8 + 0115 sightline traces the outskirt regions of the Virgo cluster where the absorber is found to have supersolar metallicity. The detection of metal lines along with H I has enabled us to confirm the presence of cool, diffuse gas possibly enriched by outflows, and tidal interactions in environments with significant galaxy density.