X-Ray View of the Shock Front in the Merging Cluster Abell 3376 with Suzaku
Abstract
We report on a Suzaku measurement of the shock feature associated with the western radio relic in the merging cluster A 3376. The temperature profile is characterized by an almost flat radial shape with kT ∼ 4 keV within 0.5r200 and a rise by about 1 keV inside the radio relic. Across the relic region (0.6-0.8r200), the temperature shows a remarkable drop from about 4.7 keV to 1.3 keV. This is clear evidence that the radio relic really corresponds to a shock front, possibly caused by a past major merger. The observed sharp changes of the temperature and electron density indicate the Mach number M ∼ 3. The radial entropy profile is flatter than the prediction (r1.1) of numerical simulations within 0.5r200, and becomes steeper around the relic region. These observed features and time-scale estimation consistently imply that the ICM around the radio relic has experienced a merger shock, and is in the middle of the process of dynamical and thermal relaxations.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- August 2012
- DOI:
- 10.1093/pasj/64.4.67
- arXiv:
- arXiv:1112.5955
- Bibcode:
- 2012PASJ...64...67A
- Keywords:
-
- galaxies: clusters: individual (Abell 3376);
- galaxies: intergalactic medium;
- shock waves;
- X-rays: galaxies: clusters;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted for publication in PASJ (12 pages, 6 figures)