天文學(xué)家們第一次目睹了來自遙遠(yuǎn)星系的狂風(fēng)

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

天文學(xué)家們第一次目睹了來自遙遠(yuǎn)星系的狂風(fēng)

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

天文學(xué)家首次直接觀測到從一個(gè)星系向外延伸數(shù)十萬光年的大規(guī)模氣體外流。

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.

他們說，這是銀河系如何給銀河系提供媒介的第一個(gè)直接證據(jù)——在星系間漂浮的星系周圍纏繞著巨大的氣體云。但除此之外，風(fēng)還揭示了大規(guī)模星系碰撞的一些瘋狂動(dòng)力學(xué)。

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.

這是因?yàn)檫@個(gè)名為SDSSJ211824.06+001729.4的星系，被研究人員以夏威夷的“風(fēng)”一詞命名為馬卡尼，并不是普通的天體。它實(shí)際上是一種銀河系的弗蘭肯斯坦的怪物，兩個(gè)星系相撞合并成一個(gè)緊湊而巨大的星系。

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。時(shí)不時(shí)地，兩個(gè)星系將被引力吸引在一起。實(shí)際上，不會(huì)有太多的東西碰到其他東西;相反，它們會(huì)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.

“星系合并常常導(dǎo)致星爆事件，當(dāng)合并星系中存在大量氣體被壓縮，導(dǎo)致新恒星誕生的爆發(fā)。”加州大學(xué)圣地亞哥分校天體物理學(xué)家Alison Coil解釋說。

"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."

“以馬卡尼為例，這些新恒星很可能導(dǎo)致了巨大的外流——要么是在恒星風(fēng)中，要么是在它們作為超新星爆炸時(shí)在生命的盡頭。”

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.

這與去年發(fā)表的兩篇模擬繞銀河系介質(zhì)的風(fēng)的論文是一致的。有人發(fā)現(xiàn)，銀河風(fēng)可以解釋觀測到的繞銀河介質(zhì)的性質(zhì)。另一個(gè)發(fā)現(xiàn)是，從星系合并中流出可以增加環(huán)銀河系介質(zhì)的金屬豐度。

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.

至于產(chǎn)生風(fēng)的原因，氣泡的速度和大小與星系合并引發(fā)的大規(guī)模恒星形成所產(chǎn)生的風(fēng)一致，也與這些風(fēng)的大小的理論模型一致。

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.

風(fēng)的沙漏形狀類似于其他星系中觀察到的沙漏，因?yàn)樗ツ陮ζ溥M(jìn)行了回顧。不同之處在于它的大小——以前從未在馬卡尼所產(chǎn)生的尺度上看到過銀河風(fēng)。

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

這就是將星系風(fēng)與周圍星系介質(zhì)聯(lián)系起來的不同之處。

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.

研究小組說，這是第一個(gè)直接觀察大質(zhì)量星系周圍不斷演化的環(huán)繞星系介質(zhì)的窗口。且它本身也很漂亮。

The research has been published in Nature Astronomy.

這項(xiàng)研究發(fā)表在《自然天文學(xué)》雜志上。