An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
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DOI：
10.1126/science.aai8635
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发表时间：
2017-02-24
期刊：
影响因子：
56.9
通讯作者：
Wolter, Anna
中科院分区：
文献类型：
--
作者：
Israel, Gian Luca;Belfiore, Andrea;Wolter, Anna
附近星系中的超亮X射线源（ULX）比我们银河系中的任何X射线源都要亮。ULX通常被建模为恒星质量黑洞（BH）以非常高的速率吸积或中等质量黑洞。我们目前的观测结果表明，NGC 5907 ULX是一颗X射线吸积中子星星（NS），其自旋周期从2003年的1.43秒演变到2014年的1.13秒。它有一个各向同性的峰值光度，类似于17.1兆秒差距的爱丁顿极限的1000倍。标准的吸积模型无法解释它的光度，即使假设光束发射，但强大的多极磁场可以描述它的性质。这些发现表明，其他极端的ULX（x射线光度>= 1041 erg秒（-1））可能藏有NS。
Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any x-ray source in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very high rates or intermediate-mass BHs. We present observations showing that NGC 5907 ULX is instead an x-ray accreting neutron star (NS) with a spin period evolving from 1.43 seconds in 2003 to 1.13 seconds in 2014. It has an isotropic peak luminosity of similar to 1000 times the Eddington limit for a NS at 17.1 megaparsec. Standard accretion models fail to explain its luminosity, even assuming beamed emission, but a strong multipolar magnetic field can describe its properties. These findings suggest that other extreme ULXs (x-ray luminosity >= 1041 erg second(-1)) might harbor NSs.