Study of ram pressure effects on NGC 2805 in Holmberg 124

TL;DR

This study uses GMRT archival data to analyze H I 21cm spectral line images of Holmberg 124, revealing tidal interactions, a possible tidal dwarf galaxy, and potential stripped H I clouds among its member galaxies.

Contribution

It provides new high-resolution H I observations of Holmberg 124, confirming previous tidal features and identifying new potential gas clouds and emission recovery in NGC 2805.

Findings

Detection of spectral line emission from all four galaxies.

Confirmation of a possible tidal dwarf galaxy near NGC 2820.

Possible detection of stripped H I clouds between NGC 2820 and NGC 2805.

Abstract

In this paper we present new H{\sc i} 21cm spectral line images of the poor group of late type galaxies, Holmberg 124 made using archival data from the Giant Metrewave Radio Telescope (GMRT). Holmberg 124 is a group of four late type galaxies: NGC 2805, NGC 2814, NGC 2820 and Mrk 108. We detect spectral line emission from all the four galaxies and note several signatures of tidal interactions among the member galaxies. Our results for the triplet (namely NGC 2820, NGC 2814 and Mrk 108) confirm the earlier results of Kantharia et al. (2005) notably the detection of a possible tidal dwarf galaxy to the north-east of NGC 2820. Further, in these images where the pointing center of the observations was changed, we have recovered most of the H{\sc i} emission in NGC 2805 as compared to Kantharia et al. (2005). We also report possible detection of small discrete clouds between NGC 2820 and NGC 2805 which might be stripped H{\sc i} in the intragroup medium (IGrM). However, these need confirmation.