Lyα-emitting galaxies at z = 3.1: L* progenitors experiencing rapid star formation

Eric Gawiser, Harold Francke, Kamson Lai, Kevin Schawinski, Caryl Gronwall, Robin Ciardullo, Ryan Quadri, Alvaro Orsi, L. Felipe Barrientos, Guillermo A. Blanc, Giovanni Fazio, John J. Feldmeier, Jia Sheng Huang, Leopoldo Infante, Paulina Lira, Nelson Padilla, Edward N. Taylor, Ezequiel Treister, C. Megan Urry, Pieter G. Van DokkumShanil N. Virani

Research output: Contribution to journalArticlepeer-review

260 Scopus citations


We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample of 162 Lyα-emitting (LAE) galaxies at z ≃ 3.1 discovered in deep narrowband MUSYC imaging of the Extended Chandra Deep Field-South. LAEs were selected to have observed frame equivalent widths >80 Å and emission line fluxes >1.5 × 10-17 ergs cm-2 s-1. Only 1% of our LAE sample appears to host AGNs. The LAEs exhibit a moderate spatial correlation length of r0 = 3.6-1.0+0.8 Mpc, corresponding to a bias factor b = 1.7-0.4+0.3, which implies median dark matter halo masses of log10Mmed = 10.9-0.9+0.5 M . Comparing the number density of LAEs, 1.5 ± 0.3 × 10-3 Mpc-3, with the number density of these halos finds a mean halo occupation ∼1%-10%. The evolution of galaxy bias with redshift implies that most z = 3.1 LAEs evolve into present-day galaxies with L < 2.5L*, whereas other z > 3 galaxy populations typically evolve into more massive galaxies. Halo merger trees show that z = 0 descendants occupy halos with a wide range of masses, with a median descendant mass close to that of L*. Only 30% of LAEs have sufficient stellar mass (>∼ 3 × 109 M) to yield detections in deep Spitzer IRAC imaging. A two-population SED fit to the stacked UBVRIzJK+[3.6, 4.5, 5.6, 8.0] μm fluxes of the IRAC-undetected objects finds that the typical LAE has low stellar mass (1.0-0.4+0.6 × 109 M ), moderate star formation rate (2 ± 1 M yr-1),ayoung component age of 20-10 +30 Myr, and little dust (AV < 0.2). The bestfit model has 20% of the mass in the young stellar component, but models without evolved stars are also allowed.

Original languageEnglish (US)
Pages (from-to)278-284
Number of pages7
JournalAstrophysical Journal
Issue number1
StatePublished - Dec 10 2007

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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