Evidence for Large-Scale Structure at z=2.4 From Lyman-alpha Imaging

摘要: We present deep wide-field medium-band imaging in redshifted Lyman alpha of fields surrounding HST detections faint emitters, to characterize their larger-scale environment. The radio galaxy 53W002 was previously found be part a rich grouping at z=2.39, including 5 confirmed, compact, star-forming objects. This is now shown larger structure traced by bright AGN, all contained within projected span 6.8 arcmin (3.2 Mpc). Of the 14 candidate six have been spectroscopically confirmed as active nuclei range z=2.390 +/- 0.008. Various statistical tests give significance 95-99% for reality this on sky. more extended than relaxed King model, 90% confidence level. Either configuration has yet decouple fully from Hubble expansion, or it consists subgroups which will themselves form structure. redshift measured members comparable flow across structure, may imply that seen near turnaround. We surveyed two additional z=2.4, and three contiguous z=2.6. Only single z=2.4 found, with Comparison WFPC2 surveys suggests field-to-field contrast brighter From survey alone, groupings such "cluster" must an area covering fraction <0.04 range.