论文标题
Abell 2163的Nustar观察：非热发射的限制
NuSTAR Observations of Abell 2163: Constraints on Non-thermal Emission
论文作者
论文摘要
自从硬X射线能量的Galaxy簇的群内培养基（ICM）发射的第一个非热报告以来，我们尚未明确确认具有新设施的观察结果中的IC发射。 RXTE检测到最热门已知的簇之一Abell 2163（A2163），这是一个带有巨大无线电晕的大规模合并群集，这是相对论电子IC散射CMB光子到X射线能量的推测来源。该集群的红移（Z〜0.2）允许其热和非热的无线电发射适合Nustars的FOV，从而允许深入观察，能够确认或排除RXTE报告。 IC通量对簇中的平均磁场强度有限制。为了确定A2163中的全局扩散IC发射，我们使用四个模型拟合其全局nustar频谱：单个（1T）和两个温度（2T），1T+功率定律组件（T+IC）以及多体体+功率+Power+Power Law（9T+IC）。每个代表热ICM发射的不同表征，添加了幂定律组件以表示IC发射。我们发现3-30 KEV光谱可以通过纯热发射来描述，全球平均温度为Kt =（11.8 $ \ pm $ 0.2）KEV。 IC通量被约束至$ <$ 4.0 $ $ \ times $ $ 10^{ - 12} $ $ $ $ $ $ $ $ $ $ s^{ - 1} $ $ $ $ $ cm^{ - 2} $使用1T+ic型号和$ <$ <$ <$ 1.6 $ 1.6 $ $ $ $ \ times $ $ $ $ $ $ 10^{ - 12} $ $ $ $ $ $ $ $ $ $ s^$ 2}模型，均至90％的置信度。将这些限制与VLA中的1.4 GHz扩散无线电数据相结合，我们发现平均磁场强度为$> $ 0.22 $ $ $ $$ g $和$> $> $ 0.35 $$ $ $ $ $ g $，为迄今为止A2163的这些值提供了最强的约束。
Since the first non-thermal reports of inverse Compton (IC) emission from the intracluster medium (ICM) of galaxy clusters at hard X-ray energies, we have yet to unambiguously confirm IC emission in observations with newer facilities. RXTE detected IC emission in one of the hottest known clusters, Abell 2163 (A2163), a massive merging cluster with a giant radio halo--the presumed source of relativistic electrons IC scattering CMB photons to X-ray energies. The cluster's redshift (z~0.2) allows its thermal and non-thermal radio emission to fit NuSTARS's FOV, permitting a deep observation capable of confirming or ruling out the RXTE report. The IC flux provides constraints on the average magnetic field strength in a cluster. To determine the global diffuse IC emission in A2163, we fit its global NuSTAR spectrum with four models: single (1T) and two-temperature (2T), 1T+power law component (T+IC), and multi-temperature+power law (9T+IC). Each represent different characterizations of the thermal ICM emission, with power law components added to represent IC emission. We find the 3-30 keV spectrum can be described by purely thermal emission, with a global average temperature of kT = (11.8 $\pm$ 0.2) keV. The IC flux is constrained to $<$ $4.0$ $\times$ $10^{-12}$ $erg$ $s^{-1}$ $cm^{-2}$ using the 1T+IC model and $<$ $1.6$ $\times$ $10^{-12}$ $erg$ $s^{-1}$ $cm^{-2}$ with the more physical 9T+IC model, both to 90% confidence levels. Combining these limits with 1.4 GHz diffuse radio data from the VLA, we find the average magnetic field strength to be $>$ $0.22$$μ$$G$ and $>$ $0.35$$μ$$G$, respectively, providing the strongest constraints on these values in A2163 to date.
