在银河系中心捕获的黑洞赏金

Astronomers have discovered evidence for thousands of black holes located near the center of our Milky Way galaxy using data from NASA’s Chandra X-ray Observatory.

This black hole bounty consists of stellar-mass black holes, which typically weigh between five to 30 times the mass of our Sun. These newly identified black holes were found within three light-years — a relatively short distance on cosmic scales — of the supermassive black hole at our Galaxy’s center known as Sagittarius A* (Sgr A*).

Theoretical studies of the dynamics of stars in galaxies have indicated that a large population of stellar mass black holes — as many as 20,000 — could drift inward over the eons and collect around Sgr A*. This recent analysis using Chandra data is the first observational evidence for such a black hole bounty.

A black hole by itself is invisible. However, a black hole — or neutron star — locked in close orbit with a star will pull gas from its companion (astronomers call these systems “X-ray binaries”). This material falls into a disk and heats up to millions of degrees and produces X-rays before disappearing into the black hole. Some of these X-ray binaries appear as point-like sources in the Chandra image.

Image Credit: NASA/Chandra X-Ray Observatory

天文学家利用美国宇航局钱德拉X射线天文台的数据，发现了位于我们银河系中心附近存在数千个黑洞的证据。

黑洞赏金由恒星质量的黑洞组成，通常质量是太阳质量的5到30倍。这些新发现的黑洞是在我们银河系中心被称为人马座A*（Sgr A*）的超大质量黑洞在三光年之内（相对于宇宙尺度而言是相对短的距离）发现的。

对星系中恒星动力学的理论研究表明，大量恒星质量的黑洞——多达20,000个——可能会在亿年间向内漂移，并聚集在Sgr A*周围。最近这项利用钱德拉数据进行的分析，是此类黑洞大量存在的第一次观测证据。

黑洞本身是看不见的。然而，如果一个黑洞或中子星与一颗恒星处于近距离的轨道上，就会从它的伴星那里吸引气体(天文学家称这些系统为“X射线双星”)。这种物质落入一个圆盘，加热到数百万度，在消失在黑洞中之前产生X射线。在钱德拉的图像中，一些X射线双星以点状的形式出现。

影像来源：NASA/Chandra X-Ray Observatory