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arXiv 1906.07730astro-ph.HE
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对星系团Abell 523的联合XMM-NuSTAR观测:逆康普顿辐射的限制

A joint XMM-NuSTAR observation of the galaxy cluster Abell 523: constraints on Inverse Compton emission

F. Cova, F. Gastaldello, D. R. Wik, W. Boschin, A. Botteon, G. Brunetti, D. A. Buote, S. De Grandi, D. Eckert, S. Ettori, L. Feretti, M. Gaspari, S. Ghizzardi, … 展开作者

F. Cova, F. Gastaldello, D. R. Wik, W. Boschin, A. Botteon, G. Brunetti, D. A. Buote, S. De Grandi, D. Eckert, S. Ettori, L. Feretti, M. Gaspari, S. Ghizzardi, G. Giovannini, M. Ghirardi, F. Govoni, S. Molendi, M. Murgia, M. Rossetti, V. Vacca

摘要:

本文介绍了在$z=0.104$上对星系团Abell 523进行的XMM-Newton和NuSTAR联合观测(200 ks)的结果。星团射电晕的特殊形态及其在射电功率P(1.4GHz)X射线光度平面上的异常位置使其成为研究射电X射线相关和寻找逆康普顿(IC)辐射的理想候选者。我们构建了热力学地图来自XMM观测详细描述的物理和动力学状态的ICM。我们在X射线和无线电发射之间的表面亮度方面进行了点对点的比较,以量化它们的形态差异。利用NuSTAR的硬X射线聚焦能力,我们在对具有多温度描述的纯热组件进行建模后,在全球和局部寻找IC发射。热力学图表明,存在一个二次合并过程,可能是负责奇特的无线电晕形态。X射线和射电表面亮度之间的比较支持这一假设,它显示了广泛的内在散射和一系列的异常值。全球NuSTAR光谱可以用纯粹的热气体排放来解释,并且没有令人信服的证据表明需要IC组件。在20-80 keV带中IC通量的$3σ$上限在$\left[2.2 - 4.0\right] \times 10^{-13} \, \mathrm{erg} \, \mathrm{s}^{-1} \, \mathrm{cm}^{-2}$范围内,这意味着磁场强度的下限在$B > [0.23 - 0.31] \, μG$范围内。在当地,我们寻找IC发射在中央区域的集群无线电晕找到一个$3σ$上限的20-80千电子伏的非热通量的$3.17 \times 10^{-14} \, \mathrm{erg} \, \mathrm{s}^{-1} \, \mathrm{cm}^{-2}$,对应的磁场强度的下限$B \gtrsim 0.81 \, μG$。

英文摘要:

We present the results of a joint XMM-Newton and NuSTAR observation (200 ks) of the galaxy cluster Abell 523 at $z=0.104$. The peculiar morphology of the cluster radio halo and its outlier position in the radio power P(1.4 GHz) - X-ray luminosity plane make it an ideal candidate for the study of radio-X-ray correlations and for the search of inverse Compton (IC) emission. We constructed thermodynamic maps derived from the XMM observations to describe in detail the physical and dynamical state of the ICM. We performed a point-to-point comparison in terms of surface brightness between the X-ray and radio emissions, to quantify their morphological discrepancies. Making use of NuSTAR's hard X-ray focusing capability, we looked for IC emission both globally and locally, after modeling the purely thermal component with a multi-temperature description. The thermodynamic maps suggest the presence of a secondary merging process that could be responsible for the peculiar radio halo morphology. This hypothesis is supported by the comparison between the X-ray and radio surface brightnesses, which shows a broad intrinsic scatter and a series of outliers. The global NuSTAR spectrum can be explained by purely thermal gas emission, and there is no convincing evidence that an IC component is needed. The $3σ$ upper limit on the IC flux in the 20-80 keV band is in the range $\left[2.2 - 4.0\right] \times 10^{-13} \, \mathrm{erg} \, \mathrm{s}^{-1} \, \mathrm{cm}^{-2}$, implying a lower limit on the magnetic field strength in the range $B > [0.23 - 0.31] \, μG$. Locally, we looked for IC emission in the central region of the cluster radio halo finding a $3σ$ upper limit on the 20-80 keV non-thermal flux of $3.17 \times 10^{-14} \, \mathrm{erg} \, \mathrm{s}^{-1} \, \mathrm{cm}^{-2}$, corresponding to a lower limit on the magnetic field strength of $B \gtrsim 0.81 \, μG$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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