Evolution of the Dependence of Rest-Frame Color and Morphology Distribution on Stellar Mass for Galaxies in the Hubble Deep Field-North
Evolution of the Dependence of Rest-Frame Color and Morphology Distribution on Stellar Mass for Galaxies in the Hubble Deep Field-North
复制标题
DOI：
10.1086/425957
复制
发表时间：
2004-09
期刊：
影响因子：
--
通讯作者：
M. Kajisawa;T. Yamada
中科院分区：
文献类型：
--
作者：
M. Kajisawa;T. Yamada
利用甚深的Subaru K‘波段成像和哈勃深场北的WFPC2/NICMOS存档数据，我们研究了恒星质量、颜色和星系形态到z~3的演化。我们主要考察了星系的静止标架U-V颜色分布作为恒星质量的函数。在0.3≲z≲2时，恒星质量约为5×10~9M☉的星系似乎分为两类。低质量星系的静止标架U-V颜色相对较蓝，在10~5×109M☉范围内，它们的颜色与恒星质量没有明显的相关性。另一方面，质量越高，星系质量越大，其U-V颜色就越红。低质量星系的平均U-V颜色随红移而逐渐变蓝，从z~0.5时的U-V~0.2变为z~2时的U-V~-0.2。然而，高质量星系群的恒星质量与静止标架U-V颜色之间的相关性在z~0.3和z~2之间似乎没有明显的变化。形态分布表明，在z≲1时，低质量星系群以盘状星系为主，而早期类型星系在高质量星系群中所占比例较大。在1 2处，可以看到更大质量的星系在109M-1010M☉范围内倾向于具有更红的U-V颜色，尽管我们只能采样恒星质量大于~1×109M☉的星系。这些结果表明，星系的恒星形成历史在很大程度上取决于它们的恒星质量。低质量恒星群可能具有较长的恒星形成时间尺度，在恒星形成率不变的假设下，它们的形成红移似乎并不比z~2高很多。当恒星质量大于~5×109M☉时，在0<；z<；星系中肯定存在某种抑制恒星形成的机制。
Using very deep Subaru K′-band imaging and archival Hubble Space Telescope WFPC2/NICMOS data of the Hubble Deep Field-North, we investigate the evolution of the stellar mass, color, and morphology of galaxies to z ~ 3. We mainly examine the rest-frame U - V color distribution of galaxies as a function of stellar mass. At 0.3 ≲ z ≲ 2, galaxies seem to be divided into the two populations at around the stellar mass of ~5 × 109 M☉. The low-mass galaxies have relatively bluer rest-frame U - V color, and their color does not show a clear correlation with stellar mass over the range 108 to 5 × 109 M☉. On the other hand, at higher mass, the more massive galaxies tend to have redder U - V color. The average U - V color of the low-mass galaxies gradually becomes bluer with redshift, from U - V ~ 0.2 at z ~ 0.5 to U - V ~ -0.2 at z ~ 2. However, the correlation between the stellar mass and rest-frame U - V color of the high-mass population does not seem to change significantly between z ~ 0.3 and z ~ 2. The morphological distribution shows that at z ≲ 1, the low-mass population is dominated by disk galaxies, while the fraction of early-type galaxies is larger in the high-mass population. At 1 2, it is seen that more massive galaxies tend to have redder U - V color over the range 109-1010 M☉, although we can only sample galaxies with stellar mass larger than ~1 × 109 M☉. These results suggest that the star formation history of galaxies depends greatly on their stellar mass. The low-mass population is likely to have a relatively long star formation timescale, and under the assumption of a constant star formation rate, their formation redshifts do not seem to be much higher than z ~ 2. At stellar masses larger than ~5 × 109 M☉, there must be some mechanism that suppresses star formation in galaxies at 0 < z < 2.