We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). NuSTAR detects four non-thermal X-ray filaments, extending the detection of their power-law spectra with Γ ~ 1.3–2.3 up to ~50 keV. A morphological and spectral study of the filaments suggests that their origin may be heterogeneous, where previous studies suggested a common origin in young pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission spatially correlated with the 6.4 keV Fe Kα fluorescence line emission associated with two Sgr A molecular clouds: MC1 and the Bridge. Broadband X-ray spectral analysis with a Monte-Carlo based X-ray reflection model self-consistently determined their intrinsic column density (~10^(23) cm^(−2)), primary X-ray spectra (power-laws with Γ ~ 2) and set a lower limit of the X-ray luminosity of Sgr A* flare illuminating the Sgr A clouds to L_X ≳ 10^(38) erg s^(−1). Above ~20 keV, hard X-ray emission in the central 10 pc region around Sgr A* consists of the candidate PWN G359.95–0.04 and the CHXE, possibly resulting from an unresolved population of massive CVs with white dwarf masses M_(WD) ~ 0.9 M_⊙. Spectral energy distribution analysis suggests that G359.95–0.04 is likely the hard X-ray counterpart of the ultra-high gamma-ray source HESS J1745–290, strongly favoring a leptonic origin of the GC TeV emission.
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机译:我们展示了通过NuSTAR获得的高于10 keV的银河系中心的第一个亚电弧图像。 NuSTAR将硬X射线源IGR J17456–2901解析为非热X射线灯丝,分子云,点源以及硬X射线发射(CHXE)以前未知的中心组件。 NuSTAR可检测四根非热X射线灯丝,将其幂律谱的检测范围从Γ〜1.3–2.3扩展到〜50 keV。细丝的形态学和光谱研究表明,它们的起源可能是异质的,以前的研究表明它们在年轻的脉冲星云(PWNe)中是常见的。 NuSTAR检测与空间6.4 keV FeKα荧光线发射在空间上相关的非热X射线连续发射,该发射与两个Sgr A分子云(MC1和桥)相关。使用基于Monte-Carlo的X射线反射模型进行宽带X射线光谱分析可自洽确定其固有列密度(〜10 ^(23)cm ^(-2)),主要X射线光谱(幂律与Γ〜2),将照亮Sgr A云的Sgr A *耀斑的X射线发光度的下限设定为L_X≳10 ^(38)erg s ^(-1)。高于〜20 keV时,Sgr A *周围中部10个pc区域的硬X射线发射由候选PWN G359.95–0.04和CHXE组成,这可能是由于未解析的大量CV和白矮星M_(WD )〜0.9M_⊙。光谱能量分布分析表明,G359.95–0.04可能是超高伽玛射线源HESS J1745–290的硬X射线对应物,强烈支持GC TeV发射的轻子起源。
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