SDSS-IV MaNGA: Properties of galaxies with kinematically decoupled stellar and gaseous components
SDSS-IV MaNGA: Properties of galaxies with kinematically decoupled stellar and gaseous components
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DOI：
10.1093/mnras/stw2055
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发表时间：
2016-11
影响因子：
4.8
通讯作者：
Yifei Jin;Yan-Mei Chen;Yong Shi;C. Tremonti;M. Bershady;M. Merrifield;E. Emsellem;E. Emsellem
中科院分区：
文献类型：
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作者：
Yifei Jin;Yan-Mei Chen;Yong Shi;C. Tremonti;M. Bershady;M. Merrifield;E. Emsellem;E. Emsellem
我们研究了来自MaNGA巡天的66个具有运动失调气体和恒星的星系的性质。运动失调星系的比例随星系的物理参数（M_s、SFR和sSFR）而变化。根据它们的sSFR，我们进一步将这66个星系分为三类，10个恒星形成星系，26个“绿色谷”星系和30个静止星系。不同类型的运动失调星系的性质不同，恒星形成星系具有正的Dn 4000梯度和较高的气相金属丰度，而绿色谷/静止星系具有负的Dn 4000梯度和较低的气相金属丰度。有证据表明，所有类型的运动失调星系往往生活在更孤立的环境中。基于所有这些观测结果，我们提出了一个恒星形成星系的方案，该星系具有运动学错位的气体和恒星-祖先吸积来自富含气体的矮星或宇宙网的错位气体，预先存在的气体和吸积气体之间的气体-气体碰撞的角动量抵消大大加速了气体流入，导致快速集中的中心星星形成。较高的金属丰度是由于从这个星星形成的富集。对于运动失调的绿色谷星系和静止星系，它们可能是由质量较小的卫星星系吸积运动失调气体的贫气体祖先星系形成的。
We study the properties of 66 galaxies with kinematically misaligned gas and stars from MaNGA survey. The fraction of kinematically misaligned galaxies varies with galaxy physical parameters, i.e. M∗, SFR and sSFR. According to their sSFR, we further classify these 66 galaxies into three categories, 10 star-forming, 26 ‘Green Valley’ and 30 quiescent ones. The properties of different types of kinematically misaligned galaxies are different in that the starforming ones have positive gradient in Dn4000 and higher gas-phase metallicity, while the green valley/quiescent ones have negative Dn4000 gradients and lower gas-phase metallicity on average. There is evidence that all types of the kinematically misaligned galaxies tend to live in more isolated environment. Based on all these observational results, we propose a scenario for the formation of star-forming galaxies with kinematically misaligned gas and stars − the progenitor accretes misaligned gas from a gas-rich dwarf or cosmic web, the cancellation of angular momentum from gas–gas collisions between the pre-existing gas and the accreted gas largely accelerates gas inflow, leading to fast centrally concentrated star formation. The higher metallicity is due to enrichment from this star formation. For the kinematically misaligned green valley and quiescent galaxies, they might be formed through gas-poor progenitors accreting kinematically misaligned gas from satellites which are smaller in mass.