The Relationship between Stellar Populations and Lyα Emission in Lyman Break Galaxies
Abstract
We present the results of a photometric and spectroscopic survey of 321 Lyman break galaxies (LBGs) at z ~ 3 to investigate systematically the relationship between Lyα emission and stellar populations. Lyα equivalent widths (W_(Lyα)) were calculated from rest-frame UV spectroscopy and optical/near-infrared/Spitzer photometry was used in population synthesis modeling to derive the key properties of age, dust extinction, star formation rate (SFR), and stellar mass. We directly compare the stellar populations of LBGs with and without strong Lyα emission, where we designate the former group (W_(Lyα) ≥ 20 Å) as Lyα emitters (LAEs) and the latter group (W_(Lyα) < 20 Å) as non-LAEs. This controlled method of comparing objects from the same UV luminosity distribution represents an improvement over previous studies in which the stellar populations of LBGs and narrowband-selected LAEs were contrasted, where the latter were often intrinsically fainter in broadband filters by an order of magnitude simply due to different selection criteria. Using a variety of statistical tests, we find that Lyα equivalent width and age, SFR, and dust extinction, respectively, are significantly correlated in the sense that objects with strong Lyα emission also tend to be older, lower in SFR, and less dusty than objects with weak Lyα emission, or the line in absorption. We accordingly conclude that, within the LBG sample, objects with strong Lyα emission represent a later stage of galaxy evolution in which supernovae-induced outflows have reduced the dust covering fraction. We also examined the hypothesis that the attenuation of Lyα photons is lower than that of the continuum, as proposed by some, but found no evidence to support this picture.
Additional Information
© 2010 The American Astronomical Society. Received 2009 September 4; accepted 2010 January 22; published 2010 February 17. We thank Kim Nilsson and Eric Gawiser for kindly providing their data for comparison. A.E.S. acknowledges support from the David and Lucile Packard Foundation and the Alfred P. Sloan Foundation. D.K.E. is supported by a Spitzer Fellowship through a NASA grant administrated by the Spitzer Science Center. C.C.S. has been supported by grants AST 03-07263 and AST 06-06912 from the National Science Foundation and by the David and Lucile Packard Foundation. Support for N.A.R. was provided by NASA through Hubble Fellowship grant HST-HF-01223.01 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. We also wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.Attached Files
Published - Kornei2010p7262Astrophys_J.pdf
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Additional details
- Eprint ID
- 17761
- Resolver ID
- CaltechAUTHORS:20100317-111435674
- David and Lucile Packard Foundation
- Alfred P. Sloan Foundation
- NASA Spitzer Fellowship
- AST 03-07263
- NSF
- AST 06-06912
- NSF
- HST-HF-01223.01
- NASA Hubble Fellowship
- NAS 5-26555
- NASA
- Created
-
2010-03-20Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)