Strategies for prompt searches for GRB afterglows: The discovery of the GRB 001011 optical/near-infrared counterpart using colour-colour selection
journal contributionposted on 2012-10-24, 09:05 authored by J. Gorosabel, J. U. Fynbo, J. Hjorth, C. Wolf, M. I. Andersen, H. Pedersen, L. Christensen, B. L. Jensen, P. Moller, J. Afonso, M. A. Treyer, G. Mallen-Ornelas, A. J. Castro-Tirado, A. Fruchter, J. Greiner, E. Pian, P. M. Vreeswijk, F. Frontera, L. Kaper, S. Klose, C. Kouveliotou, N. Masetti, E. Palazzi, E. Rol, I. Salamanca, N. Tanvir, R. A. M. J. Wijers, van den Heuvel E.
We report the discovery of the optical and near-infrared counterparts to GRB 001011. The GRB 001011 error box determined by Beppo-SAX was simultaneously imaged in the near-infrared by the 3.58-m New Technology Telescope and in the optical by the 1.54-m Danish Telescope ~ 8 hr after the gamma-ray event. Here we implement the colour-colour discrimination technique proposed by Rhoads (2001) and extend it using near-IR data as well. We present the results provided by an automatic colour-colour discrimination pipe-line developed to discern the different populations of objects present in the GRB 001011 error box. Our software revealed three candidates based on single-epoch images. Second-epoch observations carried out ~3.2 days after the burst revealed that the most likely candidate had faded, thus identifying it with the counterpart to the GRB. In deep R-band images obtained 7 months after the burst a faint ( $R=25.38 \pm 0.25$) elongated object, presumably the host galaxy of GRB 001011, was detected at the position of the afterglow. The GRB 001011 afterglow is the first discovered with the assistance of colour-colour diagram techniques. We discuss the advantages of using this method and its application to error boxes determined by future missions.
CitationAstronomy & Astrophysics, 2002, 384 (1), pp. 11-23
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