GRB 080517: a local, low-luminosity gamma-ray burst in a dusty galaxy at z = 0.09
Abstract
We present an analysis of the photometry and spectroscopy of the host galaxy of Swift-detected GRB 080517. From our optical spectroscopy, we identify a redshift of z = 0.089 ± 0.003, based on strong emission lines, making this a rare example of a very local, low-luminosity, long gamma-ray burst. The galaxy is detected in the radio with a flux density of S4.5 GHz = 0.22 ± 0.04 mJy - one of relatively few known gamma-ray bursts hosts with a securely measured radio flux. Both optical emission lines and a strong detection at 22 μm suggest that the host galaxy is forming stars rapidly, with an inferred star formation rate ∼16 M⊙ yr-1 and a high dust obscuration (E(B - V) > 1, based on sightlines to the nebular emission regions). The presence of a companion galaxy within a projected distance of 25 kpc, and almost identical in redshift, suggests that star formation may have been triggered by galaxy-galaxy interaction. However, fitting of the remarkably flat spectral energy distribution from the ultraviolet through to the infrared suggests that an older, 500 Myr post-starburst stellar population is present along with the ongoing star formation. We conclude that the host galaxy of GRB 080517 is a valuable addition to the still very small sample of well-studied local gamma-ray burst hosts.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2015
- DOI:
- 10.1093/mnras/stu2286
- arXiv:
- arXiv:1409.5791
- Bibcode:
- 2015MNRAS.446.3911S
- Keywords:
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- gamma-ray burst: individual: 080517;
- galaxies: distances and redshifts;
- galaxies: star formation;
- galaxies: structure;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 17 pages, minor edits to match accepted version