STELLAR POPULATIONS OF LYMAN BREAK GALAXIES AT z ≃ 1–3 IN THE HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS
STELLAR POPULATIONS OF LYMAN BREAK GALAXIES AT z ≃ 1–3 IN THE HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS
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HST/WFC3 早期发布的科学观测中 z ≃ 1-3 处莱曼裂痕星系的恒星群
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发表时间：
2012
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通讯作者：
E. Young
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作者：
N. Hathi;S. Cohen;R. Ryan;S. Finkelstein;P. McCarthy;R. Windhorst;H. Yan;A. Koekemoer;M. Rutkowski;R. O’Connell;A. Straughn;B. Balick;H. Bond;D. Calzetti;M. Disney;M. Dopita;M. Dopita;J. Frogel;D. Hall;J. Holtzman;R. Kimble;F. Paresce;A. Saha;J. Silk;J. Trauger;A. Walker;B. Whitmore;E. Young
利用哈勃空间望远镜（HST）的宽视场相机3（WFC 3）紫外可见光通道滤波器，分析了z = 1-3的莱曼破裂星系（LBG）的光谱能量分布。这些HST/WFC 3观测覆盖了GOODS-South领域的约50 arcmin 2，作为WFC 3早期释放科学计划的一部分。这些在z = 1-3的LBG是使用类似于高红移LBG的dropout选择标准来选择的。利用深多波段光度学方法对最佳拟合的SED模型进行了识别，得到了以下结果：（1）这些被剔除的LBG的光度红移估计精度在百分之几以内：（2）紫外光谱斜率β比高红移（z > 3）处的更红，而高红移处的LBG尘埃更少;（3）平均而言，z = 1-3的LBG质量更大，尘埃更多，星星形成程度更高，与具有相似光度（0.1L*<$L <$2.5L *）的高红移LBG相比，尽管它们的中值在1σ不确定度内相似。这可能意味着，在所有红移下，相同的dropout选择技术发现了物理上相似的星系;（4）这些LBG的恒星质量与它们的紫外光度成正比，对数斜率为10.46，星星形成率与它们的恒星质量成正比，对数斜率为10.90。这些关系保持真实的光度范围内探测在这项研究中的LBG从z 1.5到5。使用其他基于颜色的技术选择的恒星形成星系在z = 2时显示出类似的相关性，但为了避免任何选择偏差，并与z > 3时的LBG直接比较，z = 2时的真正莱曼断裂选择是必不可少的。未来的HST UV调查，更广泛和更深入，覆盖了大的光度范围，对于更好地了解LBG特性及其演变非常重要。
We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z ≃ 1–3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 arcmin2 in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z ≃ 1–3 are selected using dropout selection criteria similar to high-redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout-selected LBGs is accurate to within few percent; (2) the UV spectral slope β is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at z ≃ 1–3 are massive, dustier, and more highly star forming, compared to LBGs at higher redshifts with similar luminosities (0.1L* ≲ L ≲ 2.5L*), though their median values are similar within 1σ uncertainties. This could imply that identical dropout selection technique, at all redshifts, finds physically similar galaxies; and (4) the stellar masses of these LBGs are directly proportional to their UV luminosities with a logarithmic slope of ∼0.46, and star formation rates are proportional to their stellar masses with a logarithmic slope of ∼0.90. These relations hold true—within luminosities probed in this study—for LBGs from z ≃ 1.5 to 5. The star-forming galaxies selected using other color-based techniques show similar correlations at z ≃ 2, but to avoid any selection biases, and for direct comparison with LBGs at z > 3, a true Lyman break selection at z ≃ 2 is essential. The future HST UV surveys, both wider and deeper, covering a large luminosity range are important to better understand LBG properties and their evolution.