Discovery of the near-IR afterglow and of the host of GRB 030528 ^*,**

¹ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany e-mail: arau@mpe.mpg.de
² Thüringer Landessternwarte Tautenburg, 07778 Tautenburg, Germany
³ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
⁴ Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978, USA
⁵ Department of Physical Sciences, Univ. of Hertfordshire, College Lane, Hatfield Herts, AL10 9AB, UK
⁶ Instituto de Astrofísica de Andalucía (IAA-CSIC), Apartado de Correos, 3.004, 18.080 Granada, Spain
⁷ Niels Bohr Institute, Astronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
⁸ Institut d'Astrophysique CNRS, 98bis boulevard Arago, 75014 Paris, France
⁹ Technical University of Vienna, Dept. of Computing, Wiedner Hauptstrasse 10, Vienna, Austria
¹⁰ Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, 8000 Aarhus C, Denmark
¹¹ NSSTC, SD-50, 320 Sparkman Drive, Huntsville, AL 35805, USA
¹² IASF/CNR, Sezione di Bologna, Via Gobetti 101, 40129 Bologna, Italy
¹³ European Southern Observatory, Karl Schwarzschild-Strasse 2, 85748 Garching, Germany
¹⁴ INAF, Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
¹⁵ Astronomical Institute “Anton Pannekoek”, 1098 SJ Amsterdam, The Netherlands

Received: 28 June 2004
Accepted: 8 August 2004

Abstract

The rapid dissemination of an arcmin-sized HETE-2 localization of the long-duration X-ray flash GRB 030528 led to a ground-based multi-observatory follow-up campaign. We report the discovery of the near-IR afterglow, and also describe the detection of the underlying host galaxy in the optical and near-IR bands. The afterglow is classified as “optically dark” as it was not detected in the optical band. The K-band photometry presented here suggests that the lack of optical detection was simply the result of observational limitations (lack of rapid and deep observations plus high foreground extinction). Simple power law fits to the afterglow in the K-band suggest a typically decay with a slope of . The properties of the host are consistent with the idea that GRB hosts are star forming blue galaxies. The redshift of GRB 030528 can not be determined accurately, but the data favour redshifts less than unity. In addition, we present an optical and near-IR analysis of the X-ray source CXOU J170354.0–223654 from the vicinity of GRB 030528.