Morphologies of Galaxies in and around a Protocluster at z = 2.300
Morphologies of Galaxies in and around a Protocluster at z = 2.300
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z = 2.300 处原星系团内部及其周围的星系形态
DOI：
10.1086/521184
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
M. Pettini
中科院分区：
文献类型：
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作者：
A. Peter;A. Shapley;D. Law;C. Steidel;D. Erb;N. Reddy;M. Pettini
我们目前的结果，从第一个强大的调查星系形态作为环境的函数在z > 1.5。我们的研究的动机是这样一个事实，恒星形成星系包含在一个原星系团在z = 2.3的HS 1700+64领域有显着的年龄和更大的恒星质量平均比那些在类似的红移，但更典型的环境密度。在HST ACS图像的分析中，我们采用非参数统计来表征85个UV选择的恒星形成星系在z = 1.7-2.9，其中22个包含在原星系团的样本的静止帧UV形态。剩下的63个控制样本星系不在原星系团中，但它们的平均红移值也差不多，约为2.3。我们发现没有环境依赖的形态属性的分布。结合测量的形态与人口合成建模的结果，我们发现只有弱的相关性，如果有的话，形态和恒星的人口属性，如恒星质量，年龄，灭绝，和星星形成率之间。考虑到原星团星系人口普查的不完整性，以及在我们的样本中z ~ 2处的静止帧UV形态与星星形成历史之间缺乏相关性，形态特征分布中缺乏环境趋势并不奇怪。此外，使用更大的样本的光度候选人，我们比较形态分布的282紫外线选择和43近红外选择星系。虽然两个样本之间的星云度的差异似乎是一个产品的微弱的平均静止帧紫外线表面亮度的近红外选择的星系，我们发现，在最低的表面亮度星系，近红外选择的对象有显着较小的角尺寸。
We present results from the first robust investigation of galaxy morphology as a function of environment at z > 1.5. Our study is motivated by the fact that star-forming galaxies contained within a protocluster at z = 2.3 in the HS 1700+64 field have significantly older ages and larger stellar masses on average than those at similar redshifts but more typical environmental densities. In the analysis of HST ACS images, we apply nonparametric statistics to characterize the rest-frame UV morphologies of a sample of 85 UV-selected star-forming galaxies at z = 1.7-2.9, 22 of which are contained in the protocluster. The remaining 63 control sample galaxies are not in the protocluster but have a similar mean redshift of ~ 2.3. We find no environmental dependence for the distributions of morphological properties. Combining the measured morphologies with the results of population synthesis modeling, we find only weak correlations, if any, between morphological and stellar population properties such as stellar mass, age, extinction, and star formation rate. Given the incomplete census of the protocluster galaxy population, and the lack of correlation between rest-frame UV morphology and star formation history at z ~ 2 within our sample, the absence of environmental trends in the distribution of morphological properties is not surprising. In addition, using a larger sample of photometric candidates, we compare morphological distributions for 282 UV-selected and 43 near-IR-selected galaxies. While the difference in the degree of nebulosity between the two samples appears to be a by-product of the fainter average rest-frame UV surface brightness of the near-IR-selected galaxies, we find that, among the lowest surface brightness galaxies, the near-IR-selected objects have significantly smaller angular sizes.