https://scholars.lib.ntu.edu.tw/handle/123456789/624930
標題: | Spatially Resolved Stellar Kinematics from LEGA-C: Increased Rotational Support in z ∼ 0.8 Quiescent Galaxies | 作者: | Bezanson R Van Der Wel A Pacifici C Noeske K Barišić I Bell E.F Brammer G.B Calhau J Chauke P Van Dokkum P Franx M Gallazzi A Van Houdt J Labbé I Maseda M.V Munos-Mateos J.C Muzzin A Van De Sande J Sobral D Straatman C Wu P.-F. PO-FENG WU |
關鍵字: | galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: high-redshift; galaxies: kinematics and dynamics; galaxies: structure | 公開日期: | 2018 | 卷: | 858 | 期: | 1 | 來源出版物: | Astrophysical Journal | 摘要: | We present stellar rotation curves and velocity dispersion profiles for 104 quiescent galaxies at z = 0.6-1 from the Large Early Galaxy Astrophysics Census (LEGA-C) spectroscopic survey. Rotation is typically probed across 10-20 kpc, or to an average of 2.7Re. Combined with central stellar velocity dispersions (σ0) this provides the first determination of the dynamical state of a sample selected by a lack of star formation activity at large lookback time. The most massive galaxies (M∗ > 2 ×1011 Mo) generally show no or little rotation measured at 5 kpc ( in eight of ten cases), while ∼64% of less massive galaxies show significant rotation. This is reminiscent of local fast- and slow-rotating ellipticals and implies that low- and high-redshift quiescent galaxies have qualitatively similar dynamical structures. We compare distributions at z ∼ 0.8 and the present day by re-binning and smoothing the kinematic maps of 91 low-redshift quiescent galaxies from the Calar Alto Legacy Integral Field Area (CALIFA) survey and find evidence for a decrease in rotational support since z ∼ 1. This result is especially strong when galaxies are compared at fixed velocity dispersion; if velocity dispersion does not evolve for individual galaxies then the rotational velocity at 5 kpc was an average of 94 ±22% higher in z ∼ 0.8 quiescent galaxies than today. Considering that the number of quiescent galaxies grows with time and that new additions to the population descend from rotationally supported star-forming galaxies, our results imply that quiescent galaxies must lose angular momentum between z ∼ 1 and the present, presumably through dissipationless merging, and/or that the mechanism that transforms star-forming galaxies also reduces their rotational support. © 2018. The American Astronomical Society. All rights reserved. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047201665&doi=10.3847%2f1538-4357%2faabc55&partnerID=40&md5=b727f069e6b16acae8facdf065da1bad https://scholars.lib.ntu.edu.tw/handle/123456789/624930 |
ISSN: | 0004637X | DOI: | 10.3847/1538-4357/aabc55 |
顯示於: | 天文物理研究所 |
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