J. Greiner, Max-Planck Institut für Extraterrestrische Physik
T. Krühler, Max-Planck Institut für Extraterrestrische Physik & Universe Cluster, Technische Universität München
J. P. U. Fynbo, Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen
A. Rossi, Thüringer Landessternwarte Tautenburg
R. Schwarz, Astrophysical Institute Potsdam
S. Klose, Thüringer Landessternwarte Tautenburg
S. Savaglio, Max-Planck Institut für Extraterrestrische Physik
N. R. Tanvir, Department of Physics and Astronomy, University of Leicester
S. McBreen, Max-Planck Institut für Extraterrestrische Physik
T Totani, Kyoto University
B B. Zhang, University of Nevada
X F. Wu, Pennsylvania State University - Main Campus
D Watson, University of Copenhagen
S D. Barthelmy, NASA-GSFC
A P. Beardmore, University of Leicester
P Ferrero, Thüringer Landessternwarte Tautenburg
N Gehrels, NASA-GSFC
D A. Kann, Thüringer Landessternwarte Tautenburg
N Kawai, Tokyo Institute of Polytechnics
A Küpcü Yoldaş, European Southern Observatory
P Mészáros, Pennsylvania State University
B Milvang-Jensen, University of Copenhagen
S R. Oates, University College London
D Pierini, Max-Planck-Institut für extraterrestrische Physik
P Schady, University College London
K Toma, Pennsylvania State University
P M. Vreeswijk, University of Copenhagen
A Yoldas, Max-Planck-Institut für extraterrestrische Physik
B Zhang, University of Nevada
P Afonso, Max-Planck-Institut für extraterrestrische Physik
K Aoki, National Astronomical Observatory of Japan
D N. Burrows, Pennsylvania State University - Berks
C Clemens, Max-Planck-Institut für extraterrestrische Physik
R Filgas, Max-Planck-Institut für extraterrestrische Physik
Z Haiman, Columbia University
Dieter H. Hartmann, Clemson UniversityFollow

Document Type


Publication Date

Spring 3-10-2009

Publication Title

The Astrophysical Journal






The American Astronomical Society


We report on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND, which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i and z bands. Spectroscopy obtained at the ESO-VLT revealed a continuum extending down to λ = 9400 Å, and zero flux for 7500 Å<λ< 9400 Å, which we interpret as the onset of a Gunn–Peterson trough at z = 6.695± 0.025 (95.5% confidence level), making GRB 080913 the highest-redshift gamma-ray burst (GRB) to date, and more distant than the highest-redshift QSO. We note that many redshift indicators that are based on promptly available burst or afterglow properties have failed for GRB 080913. We report on our follow-up campaign and compare the properties of GRB 080913 with bursts at lower redshift. In particular, since the afterglow of this burst is fainter than typical for GRBs, we show that 2 m class telescopes can identify most high-redshift GRBs.


Additional authors: G. Hasinger, J. Hjorth,E.Jehin, A. J. Levan,E.W.Liang, D. Malesani, T.-S. Pyo, S. Schulze, G. Szokoly, K. Terada, K. Wiersema