  High resolution observations of cluster of galaxies by Chandra have revealed
the existence of an X-ray emitting comet-like galaxy C153 in the core of
cluster of galaxies A2125. The galaxy C153 moving fast in the cluster core has
a distinct X-ray tail on one side, obviously due to ram pressure stripping,
since the galaxy C153 crossed the central region of A2125. The X-ray emitting
plasma in the tail is substantially cooler than the ambient plasma. We present
results of two-dimensional magnetohydrodynamic simulations of the time
evolution of a subclump like C153 moving in magnetized intergalactic matter.
Anisotropic heat conduction is included. We found that the magnetic fields are
essential for the existence of the cool X-ray tail, because in non-magnetized
plasma the cooler subclump tail is heated up by isotropic heat conduction from
the hot ambient plasma and does not form such a comet-like tail.

Astrophysics