Compact Lyα-emitting candidates at z ≃ 2.4 in deep medium-band Hubble Space Telescope WFPC2 images

Sebastian M. Pascarelle, Rogier Windhorst, William C. Keel

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Medium-band imaging with Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) in the F410M filter has previously revealed a population of compact Lyα 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 Lyα 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 subgalactic 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.

Original languageEnglish (US)
Pages (from-to)2659-2666
Number of pages8
JournalAstronomical Journal
Issue number6
StatePublished - Dec 1998


  • Galaxies: evolution
  • Galaxies: formation
  • Large-scale structure of universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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