Volnova, A. A.2; Pozanenko, A. S.2; Gorosabel, J.3; Perley, D. A.9; Frederiks, D. D.4; Kann, D. A.5; Rumyantsev, V. V.6; Biryukov, V. V.7; Castro-Tirado, A. J.3; Ferrero, P.8; Golenetskii, S. V.4; Klose, S.5; Loznikov, V. M.2; Minaev, P. Yu.2; Stecklum, B.5; Svinkin, D. S.4; Tsvetkova, A. E.4; Ugarte Postigo, Antonio de9; Ulanov, M. V.4
1 Dark Cosmology Centre, The Niels Bohr Institute, Faculty of Science, Københavns Universitet2 Space Research Institute (IKI), Moscow3 Instituto de Astrofísica de Andalucía (IAA-CSIC)4 Ioffe Physical-Technical Institute of the Russian Academy of Science5 Thüringer Landessternwarte Tautenburg6 Taras Shevchenko National University of Kyiv7 Institute of Astronomy, Academy of Sciences of Uzbekistan8 Instituto de Astrofisica de Canarias9 Dark Cosmology Centre, The Niels Bohr Institute, Faculty of Science, Københavns Universitet
a long, spectrally hard dust-obscured GRB in a Lyman-break galaxy at z = 2.8
We present observations of the dark gamma-ray burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in gamma- and X-rays and neither a prompt optical nor a radio afterglow was detected down to deep limits. We identified the host galaxy of the burst, which is a typical Lyman-break galaxy (LBG) with R-magnitude of 24.06 ± 0.10 mag. A redshift of the galaxy of z=2.77+0.15−0.20 is measured photometrically due to the presence of a clear, strong Lyman-break feature. The host galaxy is a small starburst galaxy with moderate intrinsic extinction (AV = 0.3) and has a star formation rate of ∼60 M⊙ yr−1 typical for LBGs. It is one of the few cases where a GRB host has been found to be a classical LBG. Using the redshift we estimate the isotropic-equivalent radiated energy of the burst to be Eiso = (1.15 ± 0.20) × 1054 erg. We also provide evidence in favour of the hypothesis that the darkness of GRB 051008 is due to local absorption resulting from a dense circumburst medium.
Royal Astronomical Society. Monthly Notices, 2014, Vol 442, Issue 3, p. 2586-2599