這，是什么？黑洞？

What’s happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets’ consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at about 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages, the mergers are expected to be intense sources of gravitational waves.

活躍星系3C 75的核心發(fā)生什么事？這幅結(jié)合X射線（藍(lán)）及射電（粉紅）數(shù)據(jù)的影像里之二個(gè)亮斑，是二顆相互旋繞的超大質(zhì)量黑洞，它們也是龐大射電源3C 75的能量源。這二個(gè)相隔約25,000光年的超大質(zhì)量黑洞，周圍環(huán)繞著溫度高達(dá)數(shù)百萬(wàn)度的X射線輻射云氣，也會(huì)射出相對(duì)論性的粒子噴流。它們是位在Abell 400星系團(tuán)內(nèi)，離我們約有3億光年遠(yuǎn)的2個(gè)合并中的星系之核心。天文學(xué)家認(rèn)為這二個(gè)超大質(zhì)量黑洞，是被重力束縛在一起的雙黑洞系統(tǒng)，部份理由是噴流之所以具有向后噴灑的外觀，極可能是它們以每秒1,200公里的高速一起穿過(guò)熾熱星系團(tuán)氣體所致。而在擁擠的星系團(tuán)里，這類壯觀的合并事件被認(rèn)為是遙遠(yuǎn)宇宙中很常見的現(xiàn)象。在合并的最后階段，預(yù)期它們將會(huì)成為很強(qiáng)烈的引力波源。（BySASU北斗星辰）

明日預(yù)告：Milky Way doomed