论文标题
Sgr A*在230 GHz时的通量密度的时间变化
Time Variations in the Flux Density of Sgr A* at 230 GHz Detected with ALMA
论文作者
论文摘要
银河中心SGR A*的无线电来源是主要的超级质量黑洞候选者，因此是我们对它们的理解的关键。已经发现了Atacama大毫米/亚毫米阵列（ALMA）周期5观测值的SGR A*的230 GHz带通量的时间变化。在217.5、219.5和234.0 GHz的1分钟快照中测量SGR A*的通量密度，我们获得了十70分钟的光曲线。光曲线在几十分钟和每小时尺度上显示出变化。较短的时间尺度类似于$ 4 \ times 10^{6} $ $ m _ {\ odot} $黑洞的最内向稳定圆形轨道的轨道时期，这表明该变化起源于Sgr a*的附近。我们还没有检测到217.5至234.0 GHz之间的时间滞后以及光谱指数对通量密度的依赖性。
A radio source at the Galactic center Sgr A* is a prime supermassive black hole candidate and therefore key to developing our understanding of them. Time variations in the 230 GHz band flux of Sgr A* have been found with the Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 5 observations. Measuring the flux density of Sgr A* in 1 min snapshots at 217.5, 219.5, and 234.0 GHz, we obtained light curves for ten 70 min periods. The light curves show variations at a few tens of minutes and hourly scales. The shorter timescale is similar to the orbital period of the innermost stable circular orbit around a $4\times 10^{6}$ $M_{\odot}$ black hole, suggesting that the variation originates from the immediate vicinity of Sgr A*. We also detected no time lag between 217.5 and 234.0 GHz and a dependence of the spectral index on the flux density.
