2017/09/18 by Isak G. B. Wold, Steven L. Finkelstein, Amy J. Barger +2 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Grism #Luminosity #Luminosity function #Mass-to-light ratio #Number density #Quasar #Redshift #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/aa8d6b
27 pages, 19 figures, accepted for publication in ApJ
arxiv created 2017/09/18 · openalex created_date 2017/09/25 · openalex publication_date 2017/10/20 · arxiv updated 2017/11/01 · openalex updated_date 2026/08/05
Abstract We present a flux-limited sample of z ∼ 0.3 Ly α emitters (LAEs) from Galaxy Evolution Explorer ( GALEX ) grism spectroscopic data. The published GALEX z ∼ 0.3 LAE sample is pre-selected from continuum-bright objects and thus is biased against high equivalent width (EW) LAEs. We remove this continuum pre-selection and compute the EW distribution and the luminosity function of the Ly α emission line directly from our sample. We examine the evolution of these quantities from z ∼ 0.3 to 2.2 and find that the EW distribution shows little evidence for evolution over this redshift range. As shown by previous studies, the Ly α luminosity density from star-forming (SF) galaxies declines rapidly with declining redshift. However, we find that the decline in Ly α luminosity density from z = 2.2 to z = 0.3 may simply mirror the decline seen in the H α luminosity density from z = 2.2 to z = 0.4, implying little change in the volumetric Ly α escape fraction. Finally, we show that the observed Ly α luminosity density from AGNs is comparable to the observed Ly α luminosity density from SF galaxies at z = 0.3. We suggest that this significant contribution from AGNs to the total observed Ly α luminosity density persists out to z ∼ 2.2.