天文学家们第一次目睹了来自遥远星系的狂风

For The First Time, Astronomers Witness Colossal Winds Blowing Out of a Distant Galaxy

天文学家们第一次目睹了来自遥远星系的狂风

For the first time, astronomers have directly observed the massive outflow of gas extending hundreds of thousands of light-years from a galaxy.

天文学家首次直接观测到从一个星系向外延伸数十万光年的大规模气体外流。

It is, they say, the first direct evidence of how galactic winds feed the circumgalactic medium - the vast clouds of gas that wrap around galaxies as they float in intergalactic space. But more than that, the wind also reveals some of the wild dynamics of massive galactic collisions.

他们说，这是银河系如何给银河系提供媒介的第一个直接证据——在星系间漂浮的星系周围缠绕着巨大的气体云。但除此之外，风还揭示了大规模星系碰撞的一些疯狂动力学。

That's because the galaxy - called SDSS J211824.06+001729.4 and nicknamed Makani by the researchers after the Hawaiian word for 'wind' - is no ordinary object. It's actually a sort of galactic Frankenstein's monster, two galaxies that have collided and merged to form one compact, but massive galaxy.

这是因为这个名为SDSSJ211824.06+001729.4的星系，被研究人员以夏威夷的“风”一词命名为马卡尼，并不是普通的天体。它实际上是一种银河系的弗兰肯斯坦的怪物，两个星系相撞合并成一个紧凑而巨大的星系。

Space may be mostly… well, space, but there are a lot of galaxies floating through it. Every now and again, two of these galaxies will be gravitationally drawn together. There won't actually be much stuff bumping into other stuff; instead, they merge.

太空可能主要是……好吧，太空，但是有很多星系漂浮在它上面。时不时地，两个星系将被引力吸引在一起。实际上，不会有太多的东西碰到其他东西;相反，它们会合并。

"Galaxy mergers often lead to starburst events, when a substantial amount of gas present in the merging galaxies is compressed, resulting in a burst of new star births," explained astrophysicist Alison Coil of UC San Diego.

“星系合并常常导致星爆事件，当合并星系中存在大量气体被压缩，导致新恒星诞生的爆发。”加州大学圣地亚哥分校天体物理学家Alison Coil解释说。

"Those new stars, in the case of Makani, likely caused the huge outflows - either in stellar winds or at the end of their lives when they exploded as supernovae."

“以马卡尼为例，这些新恒星很可能导致了巨大的外流——要么是在恒星风中，要么是在它们作为超新星爆炸时在生命的尽头。”

This is consistent with two papers released last year modelling the winds that drive the circumgalactic medium. One found that galactic winds can account for the observed properties of the circumgalactic medium. The other foundthat outflows from galactic mergers could increase the circumgalactic medium's metallicity.

这与去年发表的两篇模拟绕银河系介质的风的论文是一致的。有人发现，银河风可以解释观测到的绕银河介质的性质。另一个发现是，从星系合并中流出可以增加环银河系介质的金属丰度。

As for what's producing the wind, the speed and size of the bubbles are consistent with the winds produced by mass star formation triggered by a galactic merger, as well as theoretical models of the size of these winds.

至于产生风的原因，气泡的速度和大小与星系合并引发的大规模恒星形成所产生的风一致，也与这些风的大小的理论模型一致。

The hourglass shape of the winds is similar to ones that have been observed in other galaxies - something Rupke knows well, since he conducted a review of them released last year. The difference is the size - never before have galactic winds been seen on the scale produced by Makani.

风的沙漏形状类似于其他星系中观察到的沙漏，因为他去年对其进行了回顾。不同之处在于它的大小——以前从未在马卡尼所产生的尺度上看到过银河风。

This is what makes the difference when it comes to linking galactic winds to the circumgalactic medium.

这就是将星系风与周围星系介质联系起来的不同之处。

It is, the team said, one of the very first direct windows into the evolving circumgalactic medium around a massive galaxy. And it's beautiful, too.

研究小组说，这是第一个直接观察大质量星系周围不断演化的环绕星系介质的窗口。且它本身也很漂亮。

The research has been published in Nature Astronomy.

这项研究发表在《自然天文学》杂志上。