Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev-Zel'dovich effect data
Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev-Zel'dovich effect data
复制标题
DOI：
10.1093/mnras/stu2750
复制
发表时间：
2014-11
影响因子：
4.8
通讯作者：
J. Erler;K. Basu;M. Trasatti;U. Klein;F. Bertoldi
中科院分区：
文献类型：
--
作者：
J. Erler;K. Basu;M. Trasatti;U. Klein;F. Bertoldi
射电遗迹是在星系团外围发现的 Mpc 规模的弥散同步加速器源。尽管射电遗迹和星团合并冲击之间的联系尚未得到最终证明，但它们被认为与通过星团内介质传播的大规模冲击有关。我们通过 Sunyaev-Zel'dovich (SZ) 效应成像首次对著名的后发星团遗迹中的压力跃变进行了尝试性检测。SZE 数据是从普朗克首次公开的全天空数据中提取的，我们使用 2.3 GHz 的高频无线电数据来约束激波锋面的几何形状。 SZE 数据提供了压力不连续性的证据，与遗迹位置一致，无需对激波前沿位置进行任何额外的事先分析。得出的马赫数M = 2.9 (+0.8/-0.6) 与X射线和无线电结果一致。 X 射线测量不利于没有任何压力不连续性的高压“细丝”，并且考虑到已发布的对该组的质量估计，可以排除基于内落组 NGC 4839 的“子星团”模型。这些结果标志着直接测量射电遗迹压力不连续性的首次尝试，以及在星系团维里半径附近观察到的第一个 SZ 检测到的冲击特征。
Radio relics are Mpc-scale diffuse synchrotron sources found in galaxy cluster outskirts. They are believed to be associated with large-scale shocks propagating through the intra-cluster medium, although the connection between radio relics and the cluster merger shocks is not yet proven conclusively. We present a first tentative detection of a pressure jump in the well-known relic of the Coma cluster through Sunyaev-Zel'dovich (SZ) effect imaging.The SZE data are extracted from the first public all-sky data release of Planck and we use high-frequency radio data at 2.3 GHz to constrain the shock-front geometry. The SZE data provide evidence for a pressure discontinuity, consistent with the relic position, without requiring any additional prior on the shock-front location. The derived Mach number M = 2.9 (+0.8/-0.6) is consistent with X-ray and radio results. A high-pressure "filament" without any pressure discontinuity is disfavoured by X-ray measurements and a "sub-cluster" model based on the infalling group NGC 4839 can be ruled out considering the published mass estimates for this group. These results signify a first attempt towards directly measuring the pressure discontinuity for a radio relic and the first SZ-detected shock feature observed near the virial radius of a galaxy cluster.