论文标题
Abell 2244 Galaxy群集的郊区的平坦熵轮廓
The flat entropy profile at the outskirts of the Abell 2244 galaxy cluster
论文作者
论文摘要
熵是研究星系簇簇内血浆的热力学史的有利诊断。我们介绍了Abell 2244 Galaxy群集的熵曲线,这两者仅使用来自低背景Swift Swift XRT望远镜的X射线数据,以及使用Planck Y数据。仅使用X射线的熵介质推导至少对病毒半径是鲁棒的,因为与低能量下的X射线背景相比,簇亮度很大,温度由于缺乏在Energies kt> 3 keV处的簇X射线光子而在强烈界定,并且XRT背景是低,稳定和理解的。在观察到的实体角度,大约一个象限,熵径向轮廓在病毒半径处偏离幂律,这主要是由于簇温度急剧下降。当X射线光谱信息被康普顿地图替换时,确认熵轮廓的这种弯曲。块和非热压力支撑不足以恢复功率法律熵概况,因为它们必然会少:基于数值模拟,离子电子平衡也不足以恢复线性熵曲线。因此,熵曲线的弯曲似乎是坚固的,并见证了通过病毒边界流入的术中预测的减少。
Entropy is an advantageous diagnostics to study the thermodynamic history of the intracluster plasma of galaxy clusters. We present the entropy profile of the Abell 2244 galaxy cluster derived both exclusively using X-ray data from the low-background Swift XRT telescope and also using Planck y data. The entropy profile derivation using X-rays only is robust at least to the virial radius because the cluster brightness is large compared to the X-ray background at low energies, temperature is strongly bounded by the lack of cluster X-ray photons at energies kT>3 keV, and the XRT background is low, stable and understood. In the observed solid angle, about one quadrant, the entropy radial profile deviates from a power-law at the virial radius, mainly because of a sharp drop of the cluster temperature. This bending of the entropy profile is confirmed when X-ray spectral information is replaced by the Compton map. Clumping and non-thermal pressure support are insufficient to restore a power law entropy profile because they are bound to be small by: a) the agreement between mass estimates from different tracers (gas and galaxies), b) the agreement between entropy profile determinations based on combinations of observables with different sensitivities and systematics, and c) the low value of clumping as estimated using the azimuthal scatter and the gas fraction. Based on numerical simulations, ion-electron equilibration is also insufficient to restore a linear entropy profile. Therefore, the bending of the entropy profiles seems to be robustly derived and witnesses the teoretically-predicted decrease in the inflow through the virial boundary.