期刊
ASTROPHYSICAL JOURNAL
卷 874, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.3847/1538-4357/ab07c9
关键词
galaxies: evolution; galaxies: formation; galaxies: interactions; galaxies: kinematics and dynamics
资金
- STScI/DDRF grant
- Giacconi Fellowship at the Space Telescope Science Institute
- NASA [NAS 5-26555]
- HST archival research grant [HST-AR-15040]
- US-Israel BSF grant [2014-273]
- NSF [AST-1405962]
- Simons Foundation
- ERC Advanced Grant STARLIGHT: Formation of the First Stars [339177]
- Klauss Tschira Foundation through the HITS-Yale Program in Astrophysics (HYPA)
The majority of massive star-forming galaxies at z similar to 2 have velocity gradients suggestive of rotation, in addition to large amounts of disordered motions. In this paper, we demonstrate that it is challenging to distinguish the regular rotation of a disk galaxy from the orbital motions of merging galaxies with seeing-limited data. However, the merger fractions at z similar to 2 are likely too low for this to have a large effect on measurements of disk fractions. To determine how often mergers pass for disks, we look to galaxy formation simulations. We analyze similar to 24,000 synthetic images and kinematic maps of 31 high-resolution simulations of isolated galaxies and mergers at z similar to 2. We determine if the synthetic observations pass the criteria commonly used to identify disk galaxies and whether the results are consistent with their intrinsic dynamical states. Galaxies that are intrinsically mergers pass the disk criteria for anywhere from 0% to 100% of sightlines. The exact percentage depends strongly on the specific disk criteria adopted and weakly on the separation of the merging galaxies. Therefore, one cannot tell with certainty whether observations of an individual galaxy indicate a merger or a disk. To estimate the fraction of mergers passing as disks in current kinematics samples, we combine the probability that a merger will pass as a disk with theoretical merger fractions from a cosmological simulation. Taking the latter at face value, the observed disk fractions are overestimated by small amounts: at most by 5% at high stellar mass (10(10)-(11) M-circle dot) and 15% at low stellar mass (10(9-10) M-circle dot).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据