The Overdense Environment of a Large Lyα Nebula at z ≈ 2.7
The Overdense Environment of a Large Lyα Nebula at z ≈ 2.7
复制标题
z ≈ 2.7 处大型 Lyα 星云的过密环境
DOI：
10.1086/588606
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Y. Matsuda
中科院分区：
文献类型：
--
作者：
M. Prescott;N. Kashikawa;A. Dey;Y. Matsuda
大星云（约50 kpc）发出强烈的Lyα（也称为Lyα“斑点”），可能是正在形成的大质量星系的路标。这些来源的相对稀少，以及它们在被充分研究的星系过密度中的发现，表明它们可能与高星系密度区域有关。最大的Lyα星云之一，通过其强烈的中红外辐射，在红移z = 2.7处被发现，为这种关联提供了一个无偏见的测试。我们对Lyα星云周围30' × 26'视场范围内的Lyα发射星系（LAEs）进行了深中波段成像巡天。这是第一次在没有先验知识的情况下对Lyα星云的环境进行研究。我们发现该星云位于一个过密区域，其大小至少为20 × 50 h70−1 Mpc，相对于该区域的边缘，其LAE数密度增加了~3倍。考虑到这种超密度的预测数量，我们排除了在0.1%水平上偶然巧合的可能性。这项研究与以前的工作相结合，有力地证实了最大的Lyα星云与宇宙过密区域之间的联系。
Large nebulae (≳ 50 kpc) emitting strongly in Lyα (also known as Lyα “blobs”) are likely signposts of ongoing massive galaxy formation. The relative rarity of these sources and their discovery in well-studied galaxy overdensities suggest that they may be associated with regions of high galaxy density. One of the largest Lyα nebulae, discovered at a redshift of z ≈ 2.7 via its strong mid-infrared emission, provides an unbiased test of this association. We have carried out a deep intermediate-band imaging survey for Lyα-emitting galaxies (LAEs) within a 30' × 26' field of view around this Lyα nebula. This is the first study of the environment of a Lyα nebula found without a priori knowledge of its surroundings. We find that the nebula is located in an overdense region, at least 20 × 50 h70−1 comoving Mpc in size, showing a factor of ~3 LAE number density enhancement relative to the edge of the field. Given the predicted number of such overdensities, we rule out the possibility of a chance coincidence at the ≲1% level. This study, in conjunction with previous work, provides strong confirmation of the association between the largest Lyα nebulae and overdense regions of the universe.