Extended Lyman Alpha Emission-Line Objects at High Redshift and Galaxy Formation

扩展的巨型Ly a发射体(LyαBLOB，LAB)，扩展超过10kpc的高红移Lyα发射体是最近才发现的一个新类别的天体。有一些重要的天体，因为我们可能正在美化大质量星系的形成过程。虽然之前已知的100-200kpc大小的实验室很少，但我们最近的研究发现，在z=3.1的Ly a发射体的大规模密度峰中，存在着70多个大小为30-200kpc的实验室。在此基础上，我们扩展了我们的研究(I)进行进一步的深部和广域窄带成像测量，以研究大量Lyα发射体，特别是实验室的分布和性质，以及(Ii)通过制作新的Nb滤光片来观测较低红移z=2.4的发射体。在本次拨款期间(2005年至2006年)，我们获得了z=3.1Lyα发射体(LAE)的最宽深部窄带图像的新数据，并对其进行了分析，以研究LAE在几个10Mpc尺度上的分布和密度增强，以寻找实验室，并研究了具有很大Lyα等效宽度的LaE的性质。得到的结果如下：(1)我们评估了观测到的密度峰在z=3.1时的重要性，发现它确实是一个非常罕见的大尺度过密区。观测到如此大规模的大密度超高密度的概率极低，这意味着在高红移时LAE的大规模偏置的形成可能存在某种未知的机制。(2)巨型实验室仅在大尺度密度峰内部或附近频繁出现，这意味着过致密区确实是星系形成的“星系形成区”。(3)大等宽LAE也强烈集中在高密度峰区。

Extended giant Ly a emitters (Ly α Blobs, LAB), high-redshift Ly α emitters with extension of more than several 10 kpc are objects in a new category which were discovered only recently. There are important objects as we may be whitenessing the formation process of massive galaxies. While there were only a few LABs with 100-200kpc size known previously, our recent study revealed the presence of more than 70 LABs with size of 30-200kpc in the large-scale density peak of Ly a emitters at z=3.1. Based on the results, we expanded our study (i) to conduct further deep and wide-field narrow-band imaging survey to study the distribution and properties of a large number of Ly α emitters, especially LABs, and (ii) to observe emitters at lower redshift z=2.4by making a new NB filter.During the period of this grant (2005-2006) we obtained a new data of ever widest deep narrow-band images for z=3.1 Ly α emitters (LAEs) and analyzed it to study the distribution and density enhancement of LAEs over several 10Mpc scale, to search for LABs, and to study the properties of LAEs with very large Ly α equivalent width. The results obtained are as follows.(1)We evaluated the significance of the observed density peak at z=3.1 and found it is indeed a very rare over dense region of large scale. The probability that such large -scale large overdensity is observed is extremely low, which implies there should be some unknown mechanism of the large-scale bias in formation of LAEs at high redshift. (2) Giant LABs are only frequently observed inside or near the large-scale density peak which implies that the over-dense region is indeed a "galaxy-forming region" where formation of galaxies are preferentially occurring (3) LAEs with large equivalent width also strongly concentrated in the high-density peak region.