Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters Export

@article{citeulike:4037883, abstract = {We present radial entropy profiles of the intracluster medium (ICM) for a collection of 239 clusters taken from the Chandra X-ray Observatory's Data Archive. Entropy is of great interest because it controls ICM global properties and records the thermal history of a cluster. Entropy is therefore a useful quantity for studying the effects of feedback on the cluster environment and investigating any breakdown of cluster self-similarity. We find that most ICM entropy profiles are well-fit by a model which is a power-law at large radii and approaches a constant value at small radii: K(r) = K0 + K100(r/100 kpc), where K0 quantifies the typical excess of core entropy above the best fitting power-law found at larger radii. We also show that the K0 distributions of both the full archival sample and the primary HIFLUGCS sample of Reiprich (2001) are bimodal with a distinct gap between K0 \~{} 30 - 50 keV cm^2 and population peaks at K0 \~{} 15 keV cm^2 and K0 \~{} 150 keV cm^2. The effects of PSF smearing and angular resolution on best-fit K0 values are investigated using mock Chandra observations and degraded entropy profiles, respectively. We find that neither of these effects is sufficient to explain the entropy-profile flattening we measure at small radii. The influence of profile curvature and number of radial bins on best-fit K0 is also considered, and we find no indication K0 is significantly impacted by either. For completeness, we include previously unpublished optical spectroscopy of Halpha and [N II] emission lines discussed in Cavagnolo et al. (2008a). All data and results associated with this work are publicly available via the project web site.}, archivePrefix = {arXiv}, author = {Cavagnolo, Kenneth W. and Donahue, Megan and Voit, Mark G. and Sun, Ming}, citeulike-article-id = {4037883}, citeulike-linkout-0 = {http://arxiv.org/abs/0902.1802}, citeulike-linkout-1 = {http://arxiv.org/pdf/0902.1802}, day = {11}, eprint = {0902.1802}, keywords = {chandra, dataset, entropy, icm}, month = {Feb}, posted-at = {2009-02-12 08:57:13}, priority = {2}, title = {Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters}, url = {http://arxiv.org/abs/0902.1802}, year = {2009} }

TY - JOUR ID - citeulike:4037883 L3 - citeulike-article-id:4037883 N2 - We present radial entropy profiles of the intracluster medium (ICM) for a collection of 239 clusters taken from the Chandra X-ray Observatory's Data Archive. Entropy is of great interest because it controls ICM global properties and records the thermal history of a cluster. Entropy is therefore a useful quantity for studying the effects of feedback on the cluster environment and investigating any breakdown of cluster self-similarity. We find that most ICM entropy profiles are well-fit by a model which is a power-law at large radii and approaches a constant value at small radii: K(r) = K0 + K100(r/100 kpc), where K0 quantifies the typical excess of core entropy above the best fitting power-law found at larger radii. We also show that the K0 distributions of both the full archival sample and the primary HIFLUGCS sample of Reiprich (2001) are bimodal with a distinct gap between K0 ~ 30 - 50 keV cm^2 and population peaks at K0 ~ 15 keV cm^2 and K0 ~ 150 keV cm^2. The effects of PSF smearing and angular resolution on best-fit K0 values are investigated using mock Chandra observations and degraded entropy profiles, respectively. We find that neither of these effects is sufficient to explain the entropy-profile flattening we measure at small radii. The influence of profile curvature and number of radial bins on best-fit K0 is also considered, and we find no indication K0 is significantly impacted by either. For completeness, we include previously unpublished optical spectroscopy of Halpha and [N II] emission lines discussed in Cavagnolo et al. (2008a). All data and results associated with this work are publicly available via the project web site. TI - Intracluster Medium Entropy Profiles for a Chandra Archival Sample of Galaxy Clusters KW - chandra KW - dataset KW - entropy KW - icm AU - Cavagnolo, Kenneth AU - Donahue, Megan AU - Voit, Mark AU - Sun, Ming PY - 2009/Feb/11/ UR - http://arxiv.org/abs/0902.1802 ER -