期刊
ASTROPHYSICAL JOURNAL
卷 850, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.3847/1538-4357/aa9576
关键词
galaxies: dwarf; galaxies: fundamental parameters; galaxies: kinematics and dynamics
资金
- NOVA postdoctoral fellowship
- National Science Foundation (NSF) [AST-1411399]
- HST theory grant [AR-14281]
- NSF grant [AST-1410012, PHY-1066293]
- NASA grant [NNX15AB17G]
- NASA [809621, NNX15AB17G] Funding Source: Federal RePORTER
Within a Lambda cold dark matter (Lambda CDM) scenario, we use high-resolution cosmological simulations spanning over four orders of magnitude in galaxy mass to understand the deficit of dwarf galaxies in observed velocity functions (VFs). We measure velocities in as similar a way as possible to observations, including generating mock HI data cubes for our simulated galaxies. We demonstrate that this apples-to-apples comparison yields an observed VF in agreement with observations, reconciling the large number of low-mass halos expected in a Lambda CDM cosmological model with the low number of observed dwarfs at a given velocity. We then explore the source of the discrepancy between observations and theory and conclude that the dearth of observed dwarf galaxies is primarily explained by two effects. The first effect is that galactic rotational velocities derived from the H I linewidth severely underestimate the maximum halo velocity. The second effect is that a large fraction of halos at the lowest masses are too faint to be detected by current galaxy surveys. We find that cored DM density profiles can contribute to the lower observed velocity of galaxies but only for galaxies in which the velocity is measured interior to the size of the core (similar to 3 kpc).
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