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arXiv 1809.01154astro-ph.GAastro-ph.CO
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最大恒星形成效率和猝灭质量尺度的起源:超新星的关键作用

The origin of the mass scales for maximal star formation efficiency and quenching: the critical role of Supernovae

Bruno Henriques, Simon White, Simon Lilly, Eric Bell, Asa Bluck, Bryan Terrazas

摘要:

我们使用Henriques et al.(2015)版本的慕尼黑星系形成模型(L-GALAXIES)来研究为什么晕和恒星质量尺度在星系淬灭时随红移而恒定,并且与重子最有效地转化为恒星的尺度相一致。这个模型假设当热的晕气体吸积到一个超大质量黑洞上时,活动星系核的反馈会使中心星系熄灭。然而,我们发现超新星(SN)反馈设置两个质量尺度。当晕增长到阈值质量以上时,SNe不再能喷射物质,因此它们的热气含量增加,从而提高了中央星系的冷却速度,其冷气含量,恒星形成速度和中央黑洞的增长速度。强烈的活动星系核反馈通过抑制恒星形成的燃料供应来终止这个短暂的阶段。尽管强烈的演化的晕质量-温度关系,淬火发生在一个红移无关的晕和恒星的质量,这与重子已转换成恒星的质量与最大的效率相一致。这些巧合和巧合是由MCMC调整模型选择的特定参数的结果,以拟合在红移范围0<z<3内观测到的星系丰度和被动分数。因此,它们是观测到的星系群演化所必需的,至少在这类模型的背景下是如此。

英文摘要:

We use the Henriques et al. (2015) version of the Munich galaxy formation model (L-GALAXIES) to investigate why the halo and stellar mass scales above which galaxies are quenched are constant with redshift and coincide with the scale where baryons are most efficiently converted into stars. This model assumes that central galaxies are quenched by AGN feedback when hot halo gas accretes onto a supermassive black hole. Nevertheless, we find that supernova (SN) feedback sets both mass scales. As haloes grow above a threshold mass, SNe can no longer eject material so their hot gas content increases, enhancing the cooling rate onto the central galaxy, its cold gas content, its star formation rate and the growth rate of its central black hole. Strong AGN feedback terminates this short-lived phase by suppressing the fuel supply for star formation. Despite strong evolution of the halo mass - temperature relation, quenching occurs at a redshift-independent halo and stellar mass which coincides with the mass where baryons have been converted into stars with maximal efficiency. These regularities and coincidences are a result of the specific parameters selected by MCMC tuning of the model to fit the observed abundance and passive fraction of galaxies over the redshift range 0<z<3. Thus they are required by the observed evolution of the galaxy population, at least in the context of models of this type.

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