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arXiv 1709.09175astro-ph.GA
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SDSS-IV MaNGA:快、慢转子的不同淬灭历史

SDSS-IV MaNGA: The Different Quenching Histories of Fast and Slow Rotators

Rebecca Smethurst, Karen Masters, Chris Lintott, Anne-Marie Weijmans, Michael Merrifield, Samantha Penny, Alfonso Aragon Salamanca, Joel Brownstein, Kevin Bundy… 展开作者

Rebecca Smethurst, Karen Masters, Chris Lintott, Anne-Marie Weijmans, Michael Merrifield, Samantha Penny, Alfonso Aragon Salamanca, Joel Brownstein, Kevin Bundy, Niv Drory, David Law, Robert Nichol

摘要:

理论上不同的形成机制的快速和缓慢的旋转产生一个可观察到的差异,在他们的恒星形成历史?为了研究这一点,我们确定淬火慢旋转的MaNGA样品中选择那些躺在下面的恒星形成序列,并确定一个样品的淬火快旋转的恒星质量相匹配。这导致总共有194个运动学分类的星系,这是不可知的视觉形态。我们使用u-r和NUV-u颜色从SDSS和GALEX和现有的推理包,STARPY,进行第一次看这些星系的淬火的开始时间和指数下降率。对两个运动学群体中推断的淬灭率分布的Anderson-Darling检验表明,它们在统计学上是可区分的($3.2σ$)。我们发现,快速转子淬火在一个更广泛的范围内的速率比慢转子,符合各种各样的物理过程,如长期的演变,未成年人合并,气体吸积和环境驱动的机制。淬灭更有可能发生在快速($τ\lesssim 1~\rm{Gyr}$)的慢旋转,在协议的理论表明,慢旋转的动态快速过程中形成的,如主要合并。有趣的是,我们还发现,一个子集的快速转子淬火在这些相同的快速速率作为大部分的慢转子样本。因此,我们讨论如何合并的总气体质量,而不是合并质量比,可能会决定星系的最终运动命运。

英文摘要:

Do the theorised different formation mechanisms of fast and slow rotators produce an observable difference in their star formation histories? To study this we identify quenching slow rotators in the MaNGA sample by selecting those which lie below the star forming sequence and identify a sample of quenching fast rotators which were matched in stellar mass. This results in a total sample of 194 kinematically classified galaxies, which is agnostic to visual morphology. We use u-r and NUV-u colours from SDSS and GALEX and an existing inference package, STARPY, to conduct a first look at the onset time and exponentially declining rate of quenching of these galaxies. An Anderson-Darling test on the distribution of the inferred quenching rates across the two kinematic populations reveals they are statistically distinguishable ($3.2σ$). We find that fast rotators quench at a much wider range of rates than slow rotators, consistent with a wide variety of physical processes such as secular evolution, minor mergers, gas accretion and environmentally driven mechanisms. Quenching is more likely to occur at rapid rates ($τ\lesssim 1~\rm{Gyr}$) for slow rotators, in agreement with theories suggesting slow rotators are formed in dynamically fast processes, such as major mergers. Interestingly, we also find that a subset of the fast rotators quench at these same rapid rates as the bulk of the slow rotator sample. We therefore discuss how the total gas mass of a merger, rather than the merger mass ratio, may decide a galaxy's ultimate kinematic fate.

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