skip to main content

SciTech ConnectSciTech Connect

Title: To stack or not to stack: Spectral energy distribution properties of Lyα-emitting galaxies at z = 2.1

We use the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) GOODS-S multi-wavelength catalog to identify counterparts for 20 Lyα emitting (LAE) galaxies at z = 2.1. We build several types of stacked spectral energy distributions (SEDs) of these objects. We combine photometry to form average and median flux-stacked SEDs, and postage-stamp images to form average and median image-stacked SEDs. We also introduce scaled flux stacks that eliminate the influence of variation in overall brightness. We use the SED fitting code SpeedyMC to constrain the physical properties of individual objects and stacks. Our LAEs at z = 2.1 have stellar masses ranging from 2 × 10{sup 7} M {sub ☉} to 8 × 10{sup 9} M {sub ☉} (median = 3 × 10{sup 8} M {sub ☉}), ages ranging from 4 Myr to 500 Myr (median = 100 Myr), and E(B – V) between 0.02 and 0.24 (median = 0.12). Although still low, this represents significantly more dust reddening than has been reported for LAEs at higher redshifts. We do not observe strong correlations between Lyα equivalent width (EW) and age or E(B – V). The Lyα radiative transfer (q) factors of our sample are predominantly close to one andmore » do not correlate strongly with EW or E(B – V). The absence of strong correlations with EW or q implies that Lyα radiative transfer is highly anisotropic and/or prevents Lyα photons from scattering in dusty regions. The SED parameters of the flux stacks match the average and median values of the individual objects, with the flux-scaled median SED performing best with uncertainties reduced by a factor of two. Median image-stacked SEDs provide a poor representation of the median individual object, and none of the stacking methods capture the large dispersion of LAE properties.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ; ;  [4] ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9] ;  [10]
  1. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States)
  2. Physics Department, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States)
  3. Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
  4. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
  5. Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
  6. Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States)
  7. Space Telescope Science Institute, Baltimore, MD (United States)
  8. Department of Astronomy, Oskar Klein Center, Stockholm University, Roslagstullsbacken 21, Stockholm (Sweden)
  9. Department of Physics and Astronomy, University of Pittsburgh, 3409 O'Hara St., Pittsburgh, PA 15260 (United States)
  10. Departmento de Astronomia y Astrofisica, Universidad Católica de Chile, Santiago (Chile)
Publication Date:
OSTI Identifier:
22351367
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; BRIGHTNESS; CAPTURE; CATALOGS; CORRELATIONS; DISPERSIONS; DUSTS; ENERGY SPECTRA; GALAXIES; IMAGES; MASS; PHOTOMETRY; PHOTONS; RADIANT HEAT TRANSFER; RED SHIFT; SCATTERING; STACKS; WAVELENGTHS