天文學家發(fā)現星系中有3個超大質量黑洞

天文學家發(fā)現星系中有3個超大質量黑洞

While supermassive black holes at the heart of galaxies are thought by astronomers to be fairly ubiquitous throughout the universe, researchers studying one nearby example have discovered not one, but three of these cosmic giants.

雖然天文學家認為星系中心的超大質量黑洞在整個宇宙中相當普遍，但研究附近一個例子的研究人員發(fā)現了不止一個，而是三個這樣的宇宙巨人。

Astronomers probing the center of the galaxy NGC 6240 have discovered three supermassive black holes caught in an elaborate (and doomed) dance around each other. (Photo: ESA/Hubble [CC by 4.0]/Wikimedia Commons)

The galaxy in question, labelled NGC 6240, is actually an amalgamation of smaller galaxies on a collision course with one another. Owing to its irregular butterfly shape, it was initially thought the merger underway was between only two galaxies. Instead, after new observations by the European Southern Observatory's Very Large Telescope (VLT) in Chile, the international team research team was surprised to discover the presence of three supermassive blackholes in tight proximity to one another.

這個被稱為NGC 6240的星系實際上是一些小星系相互碰撞的融合體。由于其不規(guī)則的蝴蝶形狀，它最初被認為只有兩個星系在合并。相反，在智利的歐洲南方天文臺的甚大望遠鏡進行了新的觀測之后，國際研究小組驚奇地發(fā)現了三個緊挨在一起的超大質量黑洞。

"Up until now, such a concentration of three supermassive black holes had never been discovered in the universe," Dr. Peter Weilbacher of the Leibniz Institute for Astrophysics Potsdam (AIP) and co-author of a paper published in the journal Astronomy & Astrophysics said in a statement. "The present case provides evidence of a simultaneous merging process of three galaxies along with their central black holes."

波茨坦萊布尼茨天體物理研究所(AIP)的彼得·威爾巴赫博士在一份聲明中說:“到目前為止，在宇宙中還從未發(fā)現過三個如此密集的超大質量黑洞。”“目前的情況提供了三個星系及其中心黑洞同時合并過程的證據。”

A cosmic tango of epic proportions

史詩般的宇宙探戈

The irregular galaxy NGC 6240. The northern black hole (N) is active and was known before. The zoomed-in new high-spatial resolution image shows that the southern component consists of two supermassive black holes (S1 and S2). (Photo: P Weilbacher (AIP), NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University))

New insights into NGC 6240 come courtesy of the VLT's 3D MUSE Spectrograph, an advanced instrument that operates in the visible wavelength range and allowed researchers to peer deep into the galaxy's dusty heart some 300 million light-years away from Earth. Each of the supermassive black holes has a mass of more than 90 million suns and resides in a region of space less than 3000 light-years across. For comparison, the supermassive black hole at the center of our own Milky Way, Sagittarius A*, has a mass of "only" 4 million suns.

VLT的3D MUSE光譜儀提供了對NGC 6240的新見解，這是一種先進的儀器，可以在可見波長范圍內工作，使研究人員能夠深入觀察距離地球約3億光年的星系塵埃中心。每一個超大質量黑洞的質量都超過9000萬個太陽，它們所處的空間跨度不到3000光年。相比之下，銀河系中心的超大質量黑洞人馬座A*的質量“只有”400萬個太陽。

Based on the close quarters of the three supermassive black holes, it's estimated the trio will eventually merge into one sometime over the next several hundred million years.

根據三個超大質量黑洞的近距離，估計這三個黑洞最終會在未來幾億年內合并成一個。

The research team says discoveries such as this one are crucial to understanding the evolution of galaxies over time. Up until now, it was regarded as a bit of a mystery as to how some of the largest galaxies observed, such as the six million light-year-wide giant IC 1101, could have possibly formed over only 14 billion years of the universe's existence.

研究小組表示，像這樣的發(fā)現對于理解星系隨時間的演化是至關重要的。到目前為止，對于一些被觀測到的最大的星系，比如600萬光年寬的巨型星系IC 1101，是如何可能在宇宙存在的140億年里形成的，這還被認為是一個謎。

"If, however, simultaneous merging processes of several galaxies took place, then the largest galaxies with their central supermassive black holes were able to evolve much faster," Weilbacher adds. "Our observations provide the first indication of this scenario."

“然而，如果同時發(fā)生幾個星系的合并過程，那么最大的星系和它們的中心超大質量黑洞能夠進化得更快，”Weilbacher補充說。“我們的觀察為這種情況提供了第一個跡象。”