%0 Generic %1 eckert2014stripping %A Eckert, D. %A Molendi, S. %A Owers, M. %A Gaspari, M. %A Venturi, T. %A Rudnick, L. %A Ettori, S. %A Paltani, S. %A Gastaldello, F. %A Rossetti, M. %D 2014 %K environment group stripping %T The stripping of a galaxy group diving into the massive cluster A2142 %U http://arxiv.org/abs/1408.1394 %X Structure formation in the current Universe operates through the accretion of group-scale systems onto massive clusters. The detection and study of such accreting systems is crucial to understand the build-up of the most massive virialized structures we see today. We report the discovery with XMM-Newton of an irregular X-ray substructure in the outskirts of the massive galaxy cluster Abell 2142. The tip of the X-ray emission coincides with a concentration of galaxies. The bulk of the X-ray emission of this substructure appears to be lagging behind the galaxies and extends over a projected scale of at least 800 kpc. The temperature of the gas in this region is 1.4 keV, which is a factor of ~4 lower than the surrounding medium and is typical of the virialized plasma of a galaxy group with a mass of a few 10^13M_sun. For this reason, we interpret this structure as a galaxy group in the process of being accreted onto the main dark-matter halo. The X-ray structure trailing behind the group is due to gas stripped from its original dark-matter halo as it moves through the intracluster medium (ICM). This is the longest X-ray trail reported to date. For an infall velocity of ~1,200 km s-1 we estimate that the stripped gas has been surviving in the presence of the hot ICM for at least 600 Myr, which exceeds the Spitzer conduction timescale in the medium by a factor of >~400. Such a strong suppression of conductivity is likely related to a tangled magnetic field with small coherence length and to plasma microinstabilities. The long survival time of the low-entropy intragroup medium suggests that the infalling material can eventually settle within the core of the main cluster.

@misc{eckert2014stripping, abstract = {Structure formation in the current Universe operates through the accretion of group-scale systems onto massive clusters. The detection and study of such accreting systems is crucial to understand the build-up of the most massive virialized structures we see today. We report the discovery with XMM-Newton of an irregular X-ray substructure in the outskirts of the massive galaxy cluster Abell 2142. The tip of the X-ray emission coincides with a concentration of galaxies. The bulk of the X-ray emission of this substructure appears to be lagging behind the galaxies and extends over a projected scale of at least 800 kpc. The temperature of the gas in this region is 1.4 keV, which is a factor of ~4 lower than the surrounding medium and is typical of the virialized plasma of a galaxy group with a mass of a few 10^13M_sun. For this reason, we interpret this structure as a galaxy group in the process of being accreted onto the main dark-matter halo. The X-ray structure trailing behind the group is due to gas stripped from its original dark-matter halo as it moves through the intracluster medium (ICM). This is the longest X-ray trail reported to date. For an infall velocity of ~1,200 km s-1 we estimate that the stripped gas has been surviving in the presence of the hot ICM for at least 600 Myr, which exceeds the Spitzer conduction timescale in the medium by a factor of >~400. Such a strong suppression of conductivity is likely related to a tangled magnetic field with small coherence length and to plasma microinstabilities. The long survival time of the low-entropy intragroup medium suggests that the infalling material can eventually settle within the core of the main cluster.}, added-at = {2014-08-08T09:43:46.000+0200}, author = {Eckert, D. and Molendi, S. and Owers, M. and Gaspari, M. and Venturi, T. and Rudnick, L. and Ettori, S. and Paltani, S. and Gastaldello, F. and Rossetti, M.}, biburl = {https://www.bibsonomy.org/bibtex/2cc8ac05e35b773442a5f6504e0da9569/miki}, description = {[1408.1394] The stripping of a galaxy group diving into the massive cluster A2142}, interhash = {652b7ab62e1f4d66e0290e870aed942a}, intrahash = {cc8ac05e35b773442a5f6504e0da9569}, keywords = {environment group stripping}, note = {cite arxiv:1408.1394Comment: 11 pages, 7 figures, accepted for publication in A&A}, timestamp = {2014-08-08T09:43:46.000+0200}, title = {The stripping of a galaxy group diving into the massive cluster A2142}, url = {http://arxiv.org/abs/1408.1394}, year = 2014 }