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.

16 pages, 6 figures, accepted for publication in ApJ

References in corpus (14)

• Shocks and cold fronts in galaxy clusters
• The origin of cold fronts in the cores of relaxed galaxy clusters
• Scaling Properties of a Complete X-ray Selected Galaxy Group Sample
• Contour binning: a new technique for spatially-resolved X-ray spectroscopy applied to Cassiopeia A
• The MASSIVE Survey - V. Spatially-Resolved Stellar Angular Momentum, Velocity Dispersion, and Higher Moments of the 41 Most Massive Local Early-Type Galaxies
• The Fossil Phase in the Life of a Galaxy Group
• The Effect of the AGN Feedback on the Interstellar Medium of Early-Type Galaxies: 2D Hydrodynamical Simulations of the Low-Rotation Case
• Cold Fronts: Probes of Plasma Astrophysics in Galaxy Clusters
• The central elliptical galaxy in fossil groups and formation of BCGs
• Deep Chandra observations of NGC 1404: cluster plasma physics revealed by an infalling early-type galaxy
• A Strong Merger Shock in Abell 665
• Capturing the 3D Motion of an Infalling Galaxy via Fluid Dynamics
• Fossil groups in the Millennium simulation. From the brightest to the faintest galaxies during the past 8 Gyr
• The Galaxy Cluster Merger Catalog: An Online Repository of Mock Observations from Simulated Galaxy Cluster Mergers

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• Properties of the Hot Ambient Medium of Early-type Galaxies Hosting Powerful Radio Sources
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• A UNIONS view of the brightest central galaxies of candidate fossil groups
• Candidate fossil groups in the CFHTLS: a probabilistic approach