The GROND gamma-ray burst sample

I. Overview and statistics

¹ Max-Planck Institut für extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching, Germany
² Present address: 82008 Fasanenstr. 31, München, Germany
³ Present address: 80335 Erzgiessereistr. 22, München, Germany
⁴ Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
⁵ American River College, Physics & Astronomy Dpt., 4700 College Oak Drive, Sacramento, CA 95841, U.S.A.
⁶ StubHub Inc., 120 Broadway, Suite 200, Santa Monica, CA 90401, U.S.A
⁷ Institute of Experimental and Applied Physics, Czech Technical University in Prague, Husova 240/5, 11000 Prague, Czech Republic
⁸ Visitor, University of Hawaii at Manoa, 2505 Correa Rd., Honolulu, HI 96822, U.S.A.
⁹ Hessian Research Cluster ELEMENTS, Goethe University Frankfurt, Max-von-Laue-Str. 12, 60438 Frankfurt A.M., Germany
¹⁰ Present address: 80337 Augsburgerstr. 5, München, Germany
¹¹ European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton CB10 1SD, UK
¹² Present address: Via Dante Alighieri 49, 20092 Cinisello Balsamo, (MI), Italy
¹³ UKIRT Observatory, Institute for Astronomy, 640 N. A’ohoku Place, University Park, Hilo, Hawaii 96720, USA
¹⁴ INAF – Osservatorio di Astrofisica e Scienza dello Spazio, Via Piero Gobetti 93/3, 40129 Bologna, Italy
¹⁵ Department of Physics, University of Bath, Building 3 West, Bath BA2 7AY, UK
¹⁶ Department of Astronomy, The Oskar Klein Centre, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
¹⁷ Amazon Web Services (AWS), 55 Pier 4 Blvd., Boston, MA 02210, U.S.A.
¹⁸ Influur Corporation, 1111 Brickell Ave, Miami, FL 33131, U.S.A.
¹⁹ School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK

^⋆ Corresponding author; jcg@mpe.mpg.de

Received: 19 February 2024
Accepted: 26 June 2024

Abstract

A dedicated gamma-ray burst (GRB) afterglow observing program was performed between 2007 and 2016 with GROND, a seven-channel optical and near-infrared imager at the 2.2m telescope of the Max-Planck Society at ESO/La Silla, In this first of a series of papers, we describe the GRB observing plan, providing first readings of all so far unpublished GRB afterglow measurements and some observing statistics. In total, we observed 514 GRBs with GROND, including 434 Swift-detected GRBs, representing 81% of the observable Swift sample. For GROND-observations within 30 min of the GRB trigger, the optical/NIR afterglow detection rate is 81% for long- and 57% for short-duration GRBs. We report the discovery of ten new GRB afterglows plus one candidate, along with redshift estimates (partly improved) for four GRBs and new host detections for seven GRBs. We identify the (already known) afterglow of GRB 140209A as the sixth GRB exhibiting a 2175 Å dust feature. As a side result, we identified two blazars, with one at a redshift of z = 3.8 (in the GRB 131209A field).