arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1609.04816astro-ph.HE
收藏

中子星以低爱丁顿速率吸积的深入研究:关于截断盘和外流的可能性

An in-depth study of a neutron star accreting at low Eddington rate: On the possibility of a truncated disk and an outflow

N. Degenaar, C. Pinto, J. M. Miller, R. Wijnands, D. Altamirano, F. Paerels, A. C. Fabian, D. Chakrabarty

摘要:

由于观测的挑战,我们对中子星周围低水平吸积流的了解是有限的。我们介绍了Nustar,Swift和Chandra对低质量X射线双星IGR J17062-6143的观测,该双星自2006年以来一直在爱丁顿极限的0.1%处持续吸积。我们的同步Nustar/Swift观测表明,0.5-79 keV的光谱可以用光子指数为Gamma~2的幂律定律、温度为kT_bb~0.5 keV的黑体(可能来自中子星表面)和盘反射的组合来描述。反射谱模拟表明,内吸积盘位于距离中子星Rin>100 GM/c2(>225 km)处。这种明显的截断可能是由于内盘蒸发成辐射效率低的吸积流,或者是由于中子星磁场的压力。我们的钱德拉光栅数据揭示了可能的窄发射线近1千电子伏,可以被建模为反射或碰撞电离气体,和可能的低能量吸收功能,可能指向外流的存在。我们考虑的情况下,这个中子星已经能够维持其低吸积率通过磁抑制的吸积流,这给了一些限制其磁场强度和自旋周期。在这种配置中,IGR J17062-6143可能会表现出强烈的射电喷流以及(螺旋桨驱动的)风状外流。

英文摘要:

Due to observational challenges our knowledge of low-level accretion flows around neutron stars is limited. We present Nustar, Swift and Chandra observations of the low-mass X-ray binary IGR J17062-6143, which has been persistently accreting at ~0.1 per cent of the Eddington limit since 2006. Our simultaneous Nustar/Swift observations show that the 0.5-79 keV spectrum can be described by a combination of a power law with a photon index of Gamma~2, a black body with a temperature of kT_bb~0.5 keV (presumably arising from the neutron star surface), and disk reflection. Modeling the reflection spectrum suggests that the inner accretion disk was located at R_in>100 GM/c2 (>225 km) from the neutron star. The apparent truncation may be due to evaporation of the inner disk into a radiatively-inefficient accretion flow, or due to the pressure of the neutron star magnetic field. Our Chandra gratings data reveal possible narrow emission lines near 1 keV that can be modeled as reflection or collisionally-ionized gas, and possible low-energy absorption features that could point to the presence of an outflow. We consider a scenario in which this neutron star has been able to sustain its low accretion rate through magnetic inhibition of the accretion flow, which gives some constraints on its magnetic field strength and spin period. In this configuration, IGR J17062-6143 could exhibit a strong radio jet as well as a (propeller-driven) wind-like outflow.

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。

↑