Disturbed Fossil Group Galaxy NGC 1132
Abstract
We have analyzed the Chandra archival data of NGC 1132, a well-known fossil group, i.e. a system expected to be old and relaxed long after the giant elliptical galaxy assembly. Instead, the Chandra data reveal that the hot gas morphology is disturbed and asymmetrical, with a cold front following a possible bow shock. We discuss possible origins of the disturbed hot halo, including sloshing by a nearby object, merger, ram pressure by external hotter gas and nuclear outburst. We consider that the first two mechanisms are likely explanations for the disturbed hot halo, with a slight preference for a minor merger with a low impact parameter because of the match with simulations and previous optical observations. In this case, NGC 1132 may be a rare example of unusual late mergers seen in recent simulations. Regardless of the origin of the disturbed hot halo, the paradigm of the fossil system needs to be reconsidered.
Cite
@article{arxiv.1706.04609,
title = {Disturbed Fossil Group Galaxy NGC 1132},
author = {Dong-Woo Kim and Craig Anderson and Doug Burke and Giuseppina Fabbiano and Antonella Fruscione and Jen Lauer and Michael McCollough and Doug Morgan and Amy Mossman and Ewan O'Sullivan and Alessandro Paggi and Saeqa Vrtilek and Ginevra Trinchieri},
journal= {arXiv preprint arXiv:1706.04609},
year = {2018}
}
Comments
16 pages, 6 figures, accepted for publication in ApJ