Article open access publication

CONSTRAINING THE Lyα ESCAPE FRACTION WITH FAR-INFRARED OBSERVATIONS OF Lyα EMITTERS

The Astrophysical Journal, IOP Publishing, ISSN 1538-4357

Volume 787, 1, 2014

DOI:10.1088/0004-637x/787/1/9, Dimensions: pub.1016386183,

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  1. (1) University of Copenhagen, grid.5254.6, KU
  2. (2) University of California, Irvine, grid.266093.8
  3. (3) Arizona State University, grid.215654.1
  4. (4) The University of Texas at Austin, grid.89336.37
  5. (5) Jet Propulsion Lab, grid.211367.0
  6. (6) California Institute of Technology, grid.20861.3d
  7. (7) Pennsylvania State University, grid.29857.31
  8. (8) University of Colorado Boulder, grid.266190.a
  9. (9) Virginia Tech, grid.438526.e
  10. (10) Rutgers, The State University of New Jersey, grid.430387.b
  11. (11) University of Maryland, College Park, grid.164295.d
  12. (12) Pontifical Catholic University of Chile, grid.7870.8
  13. (13) Royal Observatory, grid.440355.3
  14. (14) University of Edinburgh, grid.4305.2
  15. (15) University of British Columbia, grid.17091.3e
  16. (16) University of Sussex, grid.12082.39
  17. (17) Cornell University, grid.5386.8
  18. (18) Infrared Processing and Analysis Center, grid.496756.f
  19. (19) Durham University, grid.8250.f

Description

We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ~0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f esc(Lyα)). For the Sd SED template, the inferred LAEs f esc(Lyα) are 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f esc(Lyα) at these redshifts. Thus, if the LAEs f esc(Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f esc(Lyα) of ~10%-20% (1σ), all of which are slightly higher than the global evolution of f esc(Lyα), but consistent with it at the 2σ-3σ level.

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Times Cited: 18

Field Citation Ratio (FCR): 4.69

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Green, Accepted