Optical and near-infrared observations of the GRB 970616 error box ^*,**

¹ Laboratorio de Astrofísica Espacial y Física Fundamental (LAEFF-INTA), P.O. Box 50727, E-28080 Madrid, Spain
² Instituto de Astrofísica de Andalucía (IAA-CSIC), P.O. Box 03004, E-18080 Granada, Spain
³ Copenhagen University Observatory, Juliane Maries Vej 30 DK 2100 Copenhagen $\O$, Denmark
⁴ Astrophysikalisches Institut Potsdam, D-14482 Potsdam, Germany
⁵ Max-Planck-Institut für Astronomie, Heidelberg, Germany
⁶ Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
⁷ Danish Space Research Institute, Juliane Maries Vej 30 DK-2100 Copenhagen $\O$, Denmark

Send offprint request to: J. Gorosabel

Received: 29 December 1998
Accepted: 18 May 1999

Abstract

We report on near-infrared and optical observations of the GRB 970616 error box and of the X-ray sources discovered by ASCA and ROSAT in the region. No optical transient was found either within the IPN band or in the X-ray error boxes, similarly to other bursts, and we suggest that either considerable intrinsic absorption was present (like GRB 970828) or that the optical transient displayed a very fast decline (like GRB 980326 and GRB 980519).