Chandra observations of the galaxy group AWM 5: cool core re-heating and thermal conduction suppression TeX Export

@article{citeulike:3683087, abstract = {We present an analysis of a 40 ksec Chandra observation of the galaxy group AWM 5. It has a small (\$\sim8\$ kpc) dense cool core with a temperature of \$\sim1.2\$ keV and the temperature profile decreases at larger radii, from \$\sim3.5\$ keV just outside the core to \$\sim2\$ keV at \$\sim300\$ kpc from the center. The abundance distribution shows a "hole" in the central \$\sim10\$ kpc, where the temperature declines sharply. An abundance of at least a few times solar is observed \$\sim15-20\$ kpc from the center. The deprojected electron density profile shows a break in slope at \$\sim13\$ kpc and can be fit by two \$\beta\$-models, with \$\beta=0.72\_{-0.11}^{+0.16}\$ and \$r\_c=5.7\_{-1.5}^{+1.8}\$ kpc, for the inner part, and \$\beta=0.34\pm0.01\$ and \$r\_c=31.3\_{-5.5}^{+5.8}\$ kpc, for the outer part. The mass fraction of hot gas is fairly flat in the center and increases for \$r\>30\$ kpc up to a maximum of \$\sim6.5\%\$ at \$r\sim380\$ kpc. The gas cooling time within the central 30 kpc is smaller than a Hubble time, although the temperature only declines in the central \$\sim8\$ kpc region. This discrepancy suggests that an existing cooling core has been partially re-heated. In particular, thermal conduction could have been a significant source of re-heating. In order for heating due to conduction to balance cooling due to emission of X-rays, the conductivity must be suppressed by a large factor (at least \$\sim100\$). Past AGN activity (still visible as a radio source in the center of the group) is however the most likely source that re-heated the central regions of AWM 5.}, archivePrefix = {arXiv}, author = {Baldi, A. and Forman, W. and Jones, C. and Nulsen, P. and David, L. and Kraft, R. and Simionescu, A.}, citeulike-article-id = {3683087}, citeulike-linkout-0 = {http://arxiv.org/abs/0811.3654}, citeulike-linkout-1 = {http://arxiv.org/pdf/0811.3654}, day = {22}, eprint = {0811.3654}, keywords = {conduction, feedback, groups, profiles}, month = {Nov}, posted-at = {2008-11-25 09:17:03}, priority = {2}, title = {Chandra observations of the galaxy group AWM 5: cool core re-heating and thermal conduction suppression}, url = {http://arxiv.org/abs/0811.3654}, year = {2008} }

TY - JOUR ID - citeulike:3683087 L3 - citeulike-article-id:3683087 N2 - We present an analysis of a 40 ksec Chandra observation of the galaxy group AWM 5. It has a small ($\sim8$ kpc) dense cool core with a temperature of $\sim1.2$ keV and the temperature profile decreases at larger radii, from $\sim3.5$ keV just outside the core to $\sim2$ keV at $\sim300$ kpc from the center. The abundance distribution shows a "hole" in the central $\sim10$ kpc, where the temperature declines sharply. An abundance of at least a few times solar is observed $\sim15-20$ kpc from the center. The deprojected electron density profile shows a break in slope at $\sim13$ kpc and can be fit by two $\beta$-models, with $\beta=0.72_{-0.11}^{+0.16}$ and $r_c=5.7_{-1.5}^{+1.8}$ kpc, for the inner part, and $\beta=0.34\pm0.01$ and $r_c=31.3_{-5.5}^{+5.8}$ kpc, for the outer part. The mass fraction of hot gas is fairly flat in the center and increases for $r>30$ kpc up to a maximum of $\sim6.5%$ at $r\sim380$ kpc. The gas cooling time within the central 30 kpc is smaller than a Hubble time, although the temperature only declines in the central $\sim8$ kpc region. This discrepancy suggests that an existing cooling core has been partially re-heated. In particular, thermal conduction could have been a significant source of re-heating. In order for heating due to conduction to balance cooling due to emission of X-rays, the conductivity must be suppressed by a large factor (at least $\sim100$). Past AGN activity (still visible as a radio source in the center of the group) is however the most likely source that re-heated the central regions of AWM 5. TI - Chandra observations of the galaxy group AWM 5: cool core re-heating and thermal conduction suppression KW - conduction KW - feedback KW - groups KW - profiles AU - Baldi, A AU - Forman, W AU - Jones, C AU - Nulsen, P AU - David, L AU - Kraft, R AU - Simionescu, A PY - 2008/Nov/22/ UR - http://arxiv.org/abs/0811.3654 ER -