Article

The extreme, red afterglow of GRB 060923A: distance or dust?

N. R. TanvirDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RHA. J. LevanDepartment of Physics, University of Warwick, Coventry CV4 7ALE. RolDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RHR. L. C. StarlingDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RHJ. GorosabelInstituto de Astrofísica de Andalucía, (IAA-CSIC), Camino Bajo de Huétor 50, E-18008 Granada, SpainR. S. PriddeyCentre for Astrophysics Research, University of Hertfordshire, Hatfield. AL10 9ABD. MalesaniDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkP. JakobssonCentre for Astrophysics Research, University of Hertfordshire, Hatfield. AL10 9ABP. T. O’BrienDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RHA. O. JaunsenInstitute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, N-0315 Oslo, Norway ,J. HjorthDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkJ. P. U. FynboDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkA. MelandriAstrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Birkenhead CH41 1LDA. GombocFaculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, SloveniaB. Milvang‐JensenDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkA. S. FruchterSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218M. J. JarvisCentre for Astrophysics Research, University of Hertfordshire, Hatfield. AL10 9ABC. A. C. FernandesDepartment of Physics, university of Oxford, Keble Road, Oxford OX1 3RHT. WoldJoint Astronomy Centre, 660 N, A'ohoku Place, University Park, Hilo HI 96720, USA

2008en

ABI

Abstract

Accepted. Received; in original form Gamma-ray bursts are powerful probes of the early universe, but locating and identifying very distant GRBs remains challenging. We report here the discovery of the K-band afterglow of Swift GRB 060923A, imaged within the first hour post-burst, and the faintest so far found. It was not detected in any bluer bands to deep limits, making it a candidate very high redshift burst (z ∼&gt; 11). However, our later-time optical imaging and spectroscopy reveal a faint galaxy coincident with the GRB position which, if it is the host, implies a more moderate redshift (most likely z ∼ &lt; 2.8) and therefore that dust is the likely cause of the very red afterglow colour. This being the case, it is one of the few instances so far found of a GRB afterglow with high dust

Identifiers

DOI: 10.1111/j.1365-2966.2008.13496.x

Citations and references

Cited by 20 references

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