The Stellar Mass Content of Submillimeter-Selected Galaxies
Abstract
We present a new study of stellar mass in a sample of ~70 submillimeter-selected galaxies (SMGs) with accurate spectroscopic redshifts. We fit combinations of stellar population synthesis models and power laws to the galaxies' observed-frame optical through mid-IR spectral energy distributions (SEDs) to separate stellar emission from non-stellar near-IR continuum. The availability of spectroscopic redshifts significantly enhances our ability to determine unambiguously not only the mass and luminosity of SMGs, but also the presence and contribution of non-stellar emission to their SEDs. By separating the stellar emission from the non-stellar near-IR continuum, we find that ~50% of our sample have non-stellar contributions of less than 10% in rest-frame H band and ~10% of our sample have non-stellar contributions greater than 50%. We find that the K-band luminosity of the non-stellar continuum emission is correlated with hard X-ray luminosity, indicating an active galactic nucleus (AGN) origin of the emission. Upon subtracting this AGN-contributed continuum component from all of the galaxies in our sample, we determine a lower median stellar mass for SMGs than previous studies, ~7 × 10^(10) M_☉. We use constraints of the starburst timescale from molecular gas studies to estimate the amount of fading our sample would undergo if they passively evolve after the starburst terminates. The results suggest that typical SMGs, while among the most massive galaxies at z ~ 2, are likely to produce descendants of similar mass and luminosity to L^* galaxies in the local universe.
Additional Information
© 2011 The American Astronomical Society. Received 2011 February 15; accepted 2011 August 1; published 2011 October 4. We thank the anonymous referee for helpful suggestions which improved the clarity of the paper. We thank C. Maraston for providing us with unpublished stellar population synthesis models, as well as C. Borys, P. Capak, and K. Bundy for helpful discussions on fitting stellar population models to observed SEDs. We thank M. Swinbank for helpful discussions as well. We thank R. J. Smith and J. R. Lucey for providing their compilation of morphologies and 2MASS photometry for the Coma Cluster. We acknowledge the use of the NASA Extragalactic Database, as well as E. L. Wright's Web-based cosmology calculator. I.R.S. acknowledges support from STFC. D.M.A. acknowledges support from the Royal Society and the Leverhulme Trust.Attached Files
Published - Hainline2011p16382Astrophys_J.pdf
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Additional details
- Eprint ID
- 28320
- Resolver ID
- CaltechAUTHORS:20111206-132420264
- Science and Technology Facilities Council (STFC)
- Royal Society
- Leverhulme Trust
- Created
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2011-12-06Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)