论文标题
新颖的恒星质量黑洞GRS的模糊状态1915+105
The Novel Obscured State of Stellar-mass Black Hole GRS 1915+105
论文作者
论文摘要
GRS 1915 $+$ 105是一个恒星质量的黑洞，以表现至少12种不同类别的X射线变异性和相关的多波长行为而闻名。尽管如此巨大的可变性，但GRS 1915 $+$ 105仍然是X射线天空中最亮的来源之一。但是，在2019年初，消息来源变得非常愚蠢，显然进入了新的积聚状态。在这里，我们报告了GRS 1915 $+$ 105的大规模监测活动的结果，尼尔·盖尔斯·斯威夫特天文台。在此间隔期间，GRS的通量1915 $+$ 105逐渐减少；观察到的计数率最终下降了两个数量级。简单但稳健的光谱与这些监测观察结果拟合表明，这种新状态是由于内部遮挡的急剧和持续增加的结合以及降低的质量增生率而导致的。内部遮掩是主要效果，中值的值为$ n_ {h} = 7 \ times 10^{23}〜{\ rm cm cm}^{ - 2} $。在许多观察结果中，来源似乎是Compton-Thick。我们建议该状态应被确定为“晦涩的状态”，并讨论这种新的（或很少观察到的）积聚模式的含义。
GRS 1915$+$105 is a stellar-mass black hole that is well known for exhibiting at least 12 distinct classes of X-ray variability and correlated multi-wavelength behavior. Despite such extraordinary variability, GRS 1915$+$105 remained one of the brightest sources in the X-ray sky. However, in early 2019, the source became much fainter, apparently entering a new accretion state. Here, we report the results of an extensive, year-long monitoring campaign of GRS 1915$+$105 with the Neil Gehrels Swift Observatory. During this interval, the flux of GRS 1915$+$105 gradually diminished; the observed count rate eventually dropped by two orders of magnitude. Simple but robust spectral fits to these monitoring observations show that this new state results from the combination of a dramatic and persistent increase in internal obscuration, and a reduced mass accretion rate. The internal obscuration is the dominant effect, with a median value of $N_{H} = 7\times 10^{23}~{\rm cm}^{-2}$. In a number of observations, the source appears to be Compton-thick. We suggest that this state should be identified as the "obscured state," and discuss the implications of this new (or rarely observed) accretion mode for black holes across the mass scale.
