Detection of three gamma-ray burst host galaxies at z ∼ 6
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom)
- School of Physics, The University of Melbourne, VIC 3010 (Australia)
- CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)
- Dark Cosmology Centre, Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, DK-2100 København Ø (Denmark)
- H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
- Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)
- Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)
- Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States)
- Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
- European Southern Observatory, Karl Schwarzschild Strasse 2, D-85386 Garching (Germany)
Long-duration gamma-ray bursts (GRBs) allow us to pinpoint and study star-forming galaxies in the early universe, thanks to their orders of magnitude brighter peak luminosities compared to other astrophysical sources, and their association with the deaths of massive stars. We present Hubble Space Telescope Wide Field Camera 3 detections of three Swift GRB host galaxies lying at redshifts z = 5.913 (GRB 130606A), z = 6.295 (GRB 050904), and z = 6.327 (GRB 140515A) in the F140W (wide-JH band, λ{sub obs}∼1.4 μm) filter. The hosts have magnitudes (corrected for Galactic extinction) of m{sub λ{sub o{sub b{sub s,AB}}}}=26.34{sub −0.16}{sup +0.14},27.56{sub −0.22}{sup +0.18}, and 28.30{sub −0.33}{sup +0.25}, respectively. In all three cases, the probability of chance coincidence of lower redshift galaxies is ≲2%, indicating that the detected galaxies are most likely the GRB hosts. These are the first detections of high-redshift (z>5) GRB host galaxies in emission. The galaxies have luminosities in the range 0.1–0.6 L{sub z=6}{sup ∗} (with M{sub 1600}{sup ∗}=−20.95±0.12) and half-light radii in the range 0.6–0.9 kpc. Both their half-light radii and luminosities are consistent with existing samples of Lyman-break galaxies at z∼6. Spectroscopic analysis of the GRB afterglows indicate low metallicities ([M/H]≲−1) and low dust extinction (A{sub V}≲0.1) along the line of sight. Using stellar population synthesis models, we explore the implications of each galaxy’s luminosity for its possible star-formation history and consider the potential for emission line metallicity determination with the upcoming James Webb Space Telescope.
- OSTI ID:
- 22868909
- Journal Information:
- Astrophysical Journal, Vol. 825, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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