Spectroscopic confirmation of three redshift z ≈ 5.7 Lyα emitters from the Large-Area Lyman Alpha survey

James E. Rhoads, Arjun Dey, Sangeeta Malhotra, Daniel Stern, Hyron Spinrad, Buell T. Jannuzi, Steve Dawson, Michael J.I. Brown, Emily Landes

Research output: Contribution to journalReview articlepeer-review

176 Scopus citations


Narrowband searches for Lyα emission are an efficient way of identifying star-forming galaxies at high redshifts. We present Keck Telescope spectra confirming redshifts z ≈ 5.7 for three objects discovered in the Large-Area Lyman Alpha (LALA) survey at Kitt Peak National Observatory. All three spectra show strong, narrow emission lines with the asymmetric profile that is characteristically produced in high-redshift Lyα emitters by preferential H I absorption in the blue wing of the line. These objects are undetected in deep BW, V, R, and λ ≈ 6600 Å narrowband images from the NOAO Deep Wide-Field Survey and from LALA, as expected from Lyman break and Lyα forest absorption at redshift z ≈ 5.7. All three objects show large equivalent widths ( ≳ 150 Å in the rest frame), suggesting at least one of the following: a top-heavy initial mass function, very low stellar metallicity, or the presence of an active nucleus. We consider the case for an active nucleus to be weak in all three objects due to the limited width of the Lyα emission line (less than 500 km s -1) and the absence of any other indicator of quasar activity. The three confirmed high-redshift objects were among four spectroscopically observed targets drawn from the sample of 18 candidates presented by Rhoads & Malhotra. Thus, these spectra support the Lyα emitter population statistics from our earlier photometric study, which imply little evolution in number density from z = 5.7 to 4.5 and provide strong evidence that the reionization redshift is zr > 5.7.

Original languageEnglish (US)
Pages (from-to)1006-1013
Number of pages8
JournalAstronomical Journal
Issue number3 1767
StatePublished - Mar 2003


  • Cosmology: observations
  • Early universe
  • Galaxies: distances and redshifts galaxies: evolution
  • Galaxies: formation
  • Galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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