标题： 深中波段哈勃空间望远镜WFPC2图像中红移约为2.4的紧凑莱曼α发射体候选者 显示英文标题

标题： Compact Lyman-alpha Emitting Candidates at z~2.4 in Deep Medium-band HST WFPC2 Images

摘要： 中波段成像使用HST/WFPC2在F410M滤镜下之前已经揭示了围绕红移约2.4的射电星系53W002的一群紧凑的Lyman-alpha发射天体。 我们在另外三个随机的高纬度HST并行观测场中报告了在红移约2.4处类似的天体检测，这支持了这些天体在这些红移下构成广泛群体的观点。 这三个新场包含18个Lyman-alpha候选体，相比之下，在围绕53W002的单个WFPC2场更深度曝光中检测到了17个。 我们发现不同场之间的候选体数量存在显著差异，这表明在这一宇宙时期，星系分布中已经存在显著的大尺度结构。 在几个随机场中可能存在红移约2.4的次星系团块，这表明这些天体可能在早期宇宙中很常见，并加强了这样的论点，即这些天体可能通过分层合并负责形成一部分现今明亮星系的形成。 显示英文摘要

摘要： Medium-band imaging with HST/WFPC2 in the F410M filter has previously revealed a population of compact Lyman-alpha emission objects around the radio galaxy 53W002 at z~2.4. We report detections of similar objects at z~2.4 in random, high-latitude HST parallel observations of three additional fields, lending support to the idea that they constitute a widespread population at these redshifts. The three new fields contain 18 Lyman-alpha candidates, in contrast to the 17 detected in the deeper exposure of the single WFPC2 field around 53W002. We find substantial differences in the number of candidates from field to field, suggesting that significant large-scale structure is already present in the galaxy distribution at this cosmic epoch. The likely existence of z~2.4 sub-galactic clumps in several random fields shows that these objects may have been common in the early universe and strengthens the argument that such objects may be responsible for the formation of a fraction of the luminous present-day galaxies through hierarchical merging.