Disturbed Fossil Group Galaxy NGC 1132

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 p...

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Bibliographic Details
Published in:arXiv.org 2018-01
Main Authors: Dong-Woo, Kim, Anderson, Craig, Burke, Doug, Fabbiano, Giuseppina, Fruscione, Antonella, Lauer, Jen, McCollough, Michael, Morgan, Doug, Mossman, Amy, O'Sullivan, Ewan, Paggi, Alessandro, Vrtilek, Saeqa, Trinchieri, Ginevra
Format: Article
Language:English
Subjects:
Elliptical galaxies
External pressure
Galaxies
Morphology
Ram pressure
Online Access:Get full text
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Summary: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.
ISSN:2331-8422
DOI:10.48550/arxiv.1706.04609