Physical properties of z ~ 4 LBGs: differences between galaxies with and without Lyα emission
Physical properties of z ~ 4 LBGs: differences between galaxies with and without Lyα emission
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z ~ 4 LBG 的物理特性：有和没有 Lyα 发射的星系之间的差异
DOI：
10.1051/0004-6361:20066933
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发表时间：
2007
影响因子：
6.5
通讯作者：
E. Giallongo
中科院分区：
文献类型：
--
作者：
L. Pentericci;A. Grazian;A. Fontana;S. Salimbeni;P. Santini;C. Santis;S. Gallozzi;E. Giallongo
目标。我们分析了在GOODS-S巡天中观测到的z莱曼4破裂星系的物理性质，以研究Lyα以发射形式存在的星系与不存在或吸收的星系之间可能存在的差异。方法.这些物体是从它们的光学颜色中选择出来的，然后由Vanzella等人（2005年）用光谱法确认。从公开的光谱中，我们评估了Lyα发射的性质，并将样本分为有Lyα发射的星系和没有Lyα线的天体（即没有或吸收）。然后，我们使用完整的测光，从U波段到中红外从GOODS-MUSIC数据库，研究星系的观测特性，如紫外光谱斜率和光学中红外颜色，以及两个样本之间可能存在的差异。最后，我们使用标准的光谱拟合技术来确定星系的物理特性，例如恒星总质量，恒星年龄等，并再次研究了两个样本之间可能存在的差异。结果结果表明，Lyα发射的LBG比Lyα不发射的LBG平均年轻得多，质量也小得多.这两个族群的恒星形成都非常活跃，而且相对来说没有尘埃，尽管那些有线发射的恒星平均来说尘埃似乎更少。我们简要地讨论了这些结果的背景下，最近的莱曼破裂星系和Lyα发射体的演化模型。
Aims. We analysed the physical properties of z ∼ 4 Lyman Break Galaxies observed in the GOODS-S survey, in order to investigate possible differences between galaxies where the Lyα is present in emission, and those where the line is absent or in absorption. Methods. The objects were selected from their optical color and then spectroscopically confirmed by Vanzella et al. (2005). From the public spectra we assessed the nature of the Lyα emission and divided the sample into galaxies with Lyα in emission and objects without a Lyα line (i.e. either absent or in absorption). We then used complete photometry, from U band to mid-infrared from the GOODS-MUSIC database, to study the observational properties of the galaxies, such as UV spectral slopes and optical to mid-infrared colors, and the possible differences between the two samples. Lastly, we used standard spectral fitting techniques to determine the physical properties of the galaxies, such as total stellar mass, stellar ages and so on, and again we looked at the possible differences between the two samples. Results. Our results indicate that LBG with Lyα in emission are on average a much younger and less massive population than the LBGs without Lyα emission. Both populations are forming stars very actively and are relatively dust free, although those with line emission seem to be even less dusty on average. We briefly discuss these results in the context of recent models for the evolution of Lyman break galaxies and Lyα emitters.