AAS 202nd Meeting, May 2003
Session 11 Galaxies, Cosmology and Higher Redshift Objects
Poster, Monday, May 26, 2003, 9:20am-6:30pm, West Exhibit Hall

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[11.04] Nonthermal Emission from IC1262, a Low Temperature Galaxy Cluster

D.S. Hudson (Physics Department, University of Maryland, Baltimore County), M.J. Henriksen (Joint Center for Astrophysics, Physics Department, University of Maryland, Baltimore County)

We report an analysis of IC1262, the lowest temperature galaxy cluster known to have a diffuse nonthermal component in both the radio and X-ray. The diffuse nonthermal X-ray component is detected above the thermal spectrum in both the BeppoSAX Medium Energy Concentrator spectrometer detector and Chandra AXAF Charged Coupled Imaging Spectrometer. The smoothed flux image of the Chandra data shows that the cD galaxy is West of the peak X-ray emission, and a smoothed hardness map reveals cool gas extending to the North and South, implying a possible merger event along that axis. In addition, the flux map contains an asymmetric surface brightness feature to the South which is aligned with the diffuse radio emission. Spectral analysis reveals the source of the nonthermal emission to be a region to the South of the extended cool gas. We conclude that an object entering the cluster from the North-Northwest pulled the cD galaxy to the West of its halo, and disrupted the central cool gas. In addition, it caused a shock as it emerged to the South, which produces the the diffuse nonthermal emission detected in that region. Diffuse nonthermal emission in massive clusters (e.g. Coma, Abell 754, Abell 2256) is thought to be due to cosmic rays accelerated at shock fronts produced in major mergers. These data indicate that even a low mass system, such as IC1262, can experience a significant merger that will produce cosmic-ray acceleration at the shock front.

The author(s) of this abstract have provided an email address for comments about the abstract: dhudson@jca.umbc.edu

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.