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- · arXiv e-print (arXiv:1006.3560)
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| Title: |
| The Host Galaxies of Gamma-Ray Bursts II: A Mass-Metallicity Relation for Long-Duration Gamma-Ray Burst Host Galaxies |
| Authors: |
| Levesque, Emily M.; Kewley, Lisa J.; Berger, Edo; Jabran Zahid, H. |
| Publication: |
| eprint arXiv:1006.3560 |
| Publication Date: |
| 06/2010 |
| Origin: |
| ARXIV |
| Keywords: |
| Astrophysics - Galaxy Astrophysics, Astrophysics - High Energy Astrophysical Phenomena |
| Comment: |
| 15 pages, 6 figures; submitted to Astronomical Journal |
| Bibliographic Code: |
| 2010arXiv1006.3560L |
Abstract
We present a statistically robust mass-metallicity (M-Z) relation for long-duration gamma-ray burst (LGRB) host galaxies at z < 1. By comparing the LGRB host M-Z relation to samples representative of the general star-forming galaxy population, we conclude that LGRBs occur in host galaxies with lower metallicities than the general population, and that this trend extends to z ~ 1, with an average offset of -0.50 +/- 0.19 from the M-Z relation for star-forming galaxies. Our sample in this work includes new spectroscopic data for 6 LGRB host galaxies obtained at the Keck and Magellan telescopes, as well as 2 new host galaxies from the literature. Combined with data from our previous work, this yields a total sample of 6 LGRB host galaxies at z < 0.3 and 10 host galaxies at 0.3 < z < 1. We have determined a number of interstellar medium properties for our host galaxies using optical emission-line diagnostics, including metallicity, ionization parameter, young stellar population age, and star formation rate. Across our full sample of 16 LGRB hosts we find an average metallicity of log(O/H) + 12 = 8.4 +/- 0.3. Notably, we also measure a comparatively high metallicity of log(O/H) + 12 = 8.83 +/- 0.1 for the z = 0.296 host galaxy of GRB 050826. We also determine stellar masses (M*) for our LGRB host galaxy sample, finding a mean stellar mass of log(M*/Msun) = 9.25 (+0.19,-0.23).
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