The star formation histories of dwarf galaxies in Local Group cosmological simulations
The star formation histories of dwarf galaxies in Local Group cosmological simulations
复制标题
DOI：
10.1093/mnras/stz745
复制
发表时间：
2018-12
影响因子：
4.8
通讯作者：
Ruth A. R. Digby;J. Navarro;Azadeh Fattahi;C. Simpson;K. Oman;F. Gómez;C. Frenk;R. Grand;R. Pakmor
中科院分区：
文献类型：
--
作者：
Ruth A. R. Digby;J. Navarro;Azadeh Fattahi;C. Simpson;K. Oman;F. Gómez;C. Frenk;R. Grand;R. Pakmor
利用Apostle和Auriga宇宙学模拟研究了场型和伴型矮星系的星星形成历史。尽管在星系间有相当大的散射，但使徒矮星和御夫座矮星的SFH随星系恒星质量的变化呈现出稳健的平均趋势：平均而言，暗场矮星（105 <M星/M星< 106）的SFH稳步下降，而较亮的矮星（107 <M星/M星< 109）则表现出相反的趋势。中等质量的矮星具有大致恒定的SFH。土星表现出类似的平均趋势，但在最近的105 Gyr中，星星的形成受到了很大的抑制，这可能是由于进入其主晕后潮汐和冲压压力剥离造成的气体损失。这些简单的质量和环境的趋势是在很好的协议与本地集团（LG）矮星的光度达到最古老的主序关闭派生SFHS。星系的SFHS与较深的数据显示偏离这些趋势，但这可能是解释，至少在一定程度上，由大的星系到星系的散射，有限的样本大小，以及推断SFHS的大的不确定性。预测质量和环境趋势需要比目前更深入的光度数据，特别是对于孤立的矮星。
We use the apostle and Auriga cosmological simulations to study the star formation histories (SFHs) of field and satellite dwarf galaxies. Despite sizeable galaxy-to-galaxy scatter, the SFHs of apostle and Auriga dwarfs exhibit robust average trends with galaxy stellar mass: faint field dwarfs (105 < Mstar/M⊙ < 106) have, on average, steadily declining SFHs, whereas brighter dwarfs (107 < Mstar/M⊙ < 109) show the opposite trend. Intermediate-mass dwarfs have roughly constant SFHs. Satellites exhibit similar average trends, but with substantially suppressed star formation in the most recent ∼5 Gyr, likely as a result of gas loss due to tidal and ram-pressure stripping after entering the haloes of their primaries. These simple mass and environmental trends are in good agreement with the derived SFHs of Local Group (LG) dwarfs whose photometry reaches the oldest main-sequence turn-off. SFHs of galaxies with less deep data show deviations from these trends, but this may be explained, at least in part, by the large galaxy-to-galaxy scatter, the limited sample size, and the large uncertainties of the inferred SFHs. Confirming the predicted mass and environmental trends will require deeper photometric data than currently available, especially for isolated dwarfs.