Widespread star formation inside galactic outflows
Widespread star formation inside galactic outflows
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DOI：
10.1093/mnras/stz564
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发表时间：
2018-06
影响因子：
4.8
通讯作者：
R. Gallagher;R. Maiolino;F. Belfiore;N. Drory;R. Riffel;R. Riffel
中科院分区：
文献类型：
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作者：
R. Gallagher;R. Maiolino;F. Belfiore;N. Drory;R. Riffel;R. Riffel
有几个模型预测，恒星可以在星系外流中形成，这将是星系演化的一种新的主要模式。对银河系外流的观测显示，它们拥有大量的致密和致密的分子气体，这为星星的形成提供了合适的条件。利用大型MANGA-SDSS 4星系巡天的积分场光谱数据，我们研究了大样本星系外流的性质。在我们的样本中，我们发现至少30%的星系流出物内部存在明显的星星形成的证据，而在多达一半的流出物中可以看到星星形成的迹象。我们还表明，即使星星的形成是突出的许多其他星系外流，这可能还没有被发现，因为诊断很容易占主导地位的存在，甚至微弱的活动星系核和冲击。如果遥远星系和类星体的大质量外流遵循当地观测到的相同的标度关系，那么在高z外流中形成的星星可以达到几百M_{\odot}~yr ^{-1}$，并可能对星系球状体成分的早期形成做出重大贡献。外流中的星星形成也可能有助于建立黑洞与其宿主球状体之间的标度关系。此外，在大轨道上爆炸的超新星可以在原地进行化学富集，并加热环星系和星系间介质。最后，在大轨道上被抛出的年轻恒星也可能有助于宇宙的再电离。
Several models have predicted that stars could form inside galactic outflows and that this would be a new major mode of galaxy evolution. Observations of galactic outflows have revealed that they host large amounts of dense and clumpy molecular gas, which provide conditions suitable for star formation. We have investigated the properties of the outflows in a large sample of galaxies by exploiting the integral field spectroscopic data of the large MaNGA-SDSS4 galaxy survey. We find evidence for prominent star formation occurring inside at least 30 per cent of the galactic outflows in our sample, whilst signs of star formation are seen in up to half of the outflows. We also show that even if star formation is prominent inside many other galactic outflows, this may have not been revealed as the diagnostics are easily dominated by the presence of even faint active galactic nucleus and shocks. If very massive outflows typical of distant galaxies and quasars follow the same scaling relations observed locally, then the star formation inside high-z outflows can be up to several 100 $\rm M_{\odot }~yr^{-1}$ and could contribute substantially to the early formation of the spheroidal component of galaxies. Star formation in outflows can also potentially contribute to establishing the scaling relations between black holes and their host spheroids. Moreover, supernovae exploding on large orbits can chemically enrich in situ and heat the circumgalactic and intergalactic medium. Finally, young stars ejected on large orbits may also contribute to the reionization of the Universe.