1208.0006 (Ido Reiss et al.)

Near-Equipartition Magnetic Fields Measured in the Cool Cores of Galaxy Clusters    [PDF]

Ido Reiss, Uri Keshet

Tangential discontinuities, seen as X-ray edges known as cold fronts (CFs), are ubiquitous in cool-core galaxy clusters. We analyze all 18 deprojected CF thermal profiles found in the literature, including three new CFs we identify (in clusters A2204 and 2A0335). We discover small but significant thermal pressure drops below all non-merger CFs, and argue that they arise from strong, near-equipartition (10-20%) magnetic fields below and parallel to the discontinuity. Such magnetization can stabilize the CF against Kelvin-Helmholtz instabilities, and explain the connection between CFs and radio minihalos.

View original: http://arxiv.org/abs/1208.0006