Molecular gas in the galaxy cluster Abell 262. CO observations of UGC 1347 and other galaxies of the cluster

TL;DR

This study investigates molecular gas content in the galaxy cluster Abell 262 using CO observations, revealing a potential deficiency in the cluster core linked to cloud stripping, supported by IRAS data and high-resolution imaging.

Contribution

It provides new CO observations of multiple galaxies in Abell 262 and models molecular gas depletion due to cirrus-like cloud stripping in the cluster core.

Findings

Evidence of molecular gas deficiency in the cluster center

IRAS data supports decreased 100 micron flux in the core

High-resolution CO imaging confirms off-nuclear molecular gas source

Abstract

We present millimeter CO line emission observations of 12 galaxies within the Abell 262 cluster, together with L_FIR data, in the context of a possible molecular gas deficiency within the region of the cluster center. Several indications of the presence of such a deficiency are highlighted and connected to a model of cirrus-like cloud stripping. The model predicts a drop in the average 100 micron flux density of galaxies in the core of the cluster compared to the average 100 micron flux density in the outer regions, which is actually indicated in the IRAS data of the cluster members. This drop is explained by the decrease in the total hydrogen column density N(H) and, therefore, also includes a decrease in the molecular gas content. In addition to results for the global CO content of the galaxy sample, high-resolution interferometric CO(1-0) observations of one of the cluster members, UGC 1347, exemplify the spatial distribution of the molecular gas in a galaxy of the cluster. With these observations, it was possible to confirm the existence of a bright off-nuclear CO-emission source and to derive molecular masses and line ratios for this source and the nucleus.