The Arecibo Galaxy Environment Survey: II. A HI view of the Abell cluster 1367 and its outskirts

TL;DR

This study uses 21 cm HI line observations to analyze the distribution and properties of galaxies in and around the Abell 1367 cluster, revealing differences between HI-selected and optically selected samples and implications for understanding cluster composition.

Contribution

First detailed HI survey of Abell 1367 showing that HI-selected galaxies have similar baryon fractions and a different large-scale distribution compared to optical observations.

Findings

HI-selected galaxies follow typical scaling relations.

All galaxies have similar baryon fractions regardless of size.

HI distribution shows almost no presence in the cluster core.

Abstract

We present 21 cm HI line observations of 5x1 square degrees centered on the local Abell cluster 1367 obtained as part of the Arecibo Galaxy Environment Survey. One hundred sources are detected (79 new HI measurements and 50 new redshifts), more than half belonging to the cluster core and its infalling region. Combining the HI data with SDSS optical imaging we show that our HI selected sample follows scaling relations similar to the ones usually observed in optically selected samples. Interestingly all galaxies in our sample appear to have nearly the same baryon fraction independently of their size, surface brightness and luminosity. The most striking difference between HI and optically selected samples resides in their large scale distribution: whereas optical and X-ray observations trace the cluster core very well, in HI there is almost no evidence of the presence of the cluster. Some implications on the determination of the cluster luminosity function and HI distribution for samples selected at different wavelength are also discussed.