A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst
A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst
复制标题
NuSTAR 对爆发中的快速共生新星 V745 Sco 的观测
DOI：
10.1093/mnrasl/slu195
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发表时间：
2014
影响因子：
4.8
通讯作者：
F. Harrison
中科院分区：
文献类型：
--
作者：
M. Orio;V. Rana;K. Page;J. Sokoloski;F. Harrison
在光学发现后10d，用NuSTAR在3-79keV X射线波段观测到快速复发的新星V745Sco。在2.7keV的温度下，测量的X射线发射与碰撞电离的光学薄等离子体是一致的。在6.7keV观察到的一条突出的铁线不需要在喷出物中增强铁。我们将X射线通量归因于受冲击的星际物质。在20keV以上的能量范围内没有观察到X射线发射，在3-20keV范围内的通量约为1.6×10^(−11)erg cm^(−2)S^(−1)。发射测量表明，平均电子密度约为10^7厘米^(−2)。用SWIFT几乎同时测量的0.3-10keV波段的X射线通量大约大40倍，这主要是由于发光的中心超软源在能量低于1keV时发出的。由于新星能谱不符合幂定律，加上没有硬X射线辐射，我们可以排除康普顿伽马射线的可能性，并将爆发第10天新星的伽马射线流量上限定为10^(−11)erg cm^(−2)S^(−1)。
The fast recurrent nova V745 Sco was observed in the 3–79 keV X-rays band with NuSTAR 10 d after the optical discovery. The measured X-ray emission is consistent with a collisionally ionized optically thin plasma at temperature of about 2.7 keV. A prominent iron line observed at 6.7 keV does not require enhanced iron in the ejecta. We attribute the X-ray flux to shocked circumstellar material. No X-ray emission was observed at energies above 20 keV, and the flux in the 3–20 keV range was about 1.6 × 10^(−11) erg cm^(−2) s^(−1). The emission measure indicates an average electron density of the order of 10^7 cm^(−2). The X-ray flux in the 0.3–10 keV band almost simultaneously measured with Swift was about 40 times larger, mainly due to the luminous central supersoft source emitting at energy below 1 keV. The fact that the NuSTAR spectrum cannot be fitted with a power law, and the lack of hard X-ray emission, allow us to rule out Comptonized gamma-rays, and to place an upper limit of the order of 10^(−11) erg cm^(−2) s^(−1) on the gamma-ray flux of the nova on the tenth day of the outburst.