Presentation 1 : Oral
XMM-newton observations of merging clusters of galaxies (PNC)
Elena Belsole, Chiara Ferrari, Herve Bourdin, Garbiel Pratt
The new X-ray satellites, XMM-Newton and Chandra, have begun to give
us a new vision of clusters of galaxies and their dynamical
status. Hydrodynamical simulations show that a merging event
strongly changes the physical characteristics of the intracluster medium, and
in particular that the temperature structure is a good
indicator of cluster formation history through merger events.
Many galaxy clusters show signs of substructure. X-ray
spectro-imaging observations are well suited to deeper investigation of the
dynamical processes behind this substructure. We present two targets from
our XMM-Newton guaranteed time programme: A3921, an off-set merger between
a main cluster and a smaller subcluster, and the bimodal cluster
A1750. In both clusters
we detect a complex temperature structure indicating interaction
in the merging direction.
The comparison between simulations and X-ray data suggests that the subcluster
in A3921 is at the distance of closest core passage. Moreover, optical
observations suggest a possible 3 body interaction.
The temperature structure of A1750 and the lack of gas distorsion in the
region of interaction give support for an early phase of merger, before core
passage.