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

Gawiser, E; Francke H.; Lai, K.; Schawinski, K; Gronwall C.; Ciardullo R.; Quadri, R; Orsi, A; Barrientos F.; Blanc, GA; Fazio, G.; Feldmeier, JJ; Huang, JS; Infante, L; Lira, P; et. al.


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. © 2007. The American Astronomical Society. All rights reserved.

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Título según WOS: Ly alpha-emitting galaxies at z=3.1: L* progenitors experiencing rapid star formation
Título según SCOPUS: Lya-emitting galaxies at z = 3.1: L* progenitors experiencing rapid star formation
Volumen: 671
Número: 1
Fecha de publicación: 2007
Página de inicio: 278
Página final: 284
Idioma: English