TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1439 SUBJECT: GRB/XRF 020427, detection of an underlying system with the VLT DATE: 02/06/25 05:45:40 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia GRB/XRF 020427, detection of an underlying system with the VLT ------------------------------------------------ A. J. Castro-Tirado and J. Gorosabel (Instituto de Astrofísica de Andalucía, IAA-CSIC, Granada) C. Sánchez-Fernández (ESA-VILSPA, Madrid) N. Lund and S. Brandt (DSRI, Copenhagen) J. M. Castro Cerón (ROA, San Fernando) communicate: "We have observed the field of the GRB/XRF 020427 (GCN Circulars 1383, 1384, 1386, 1390, 1394) on 11.388-11.397 June 2002 with the 8.2-m VLT telescope at Paranal ESO's observatory (equipped with FORS2). Imagery was obtained in the B- and R-bands (300-s exposure time each) under rather poor seeing conditions (1".2). The position of the likely X-ray afterglow detected by BSAX and followed-up by Chandra (GCN Circulars 1387, 1392) is coincident with the north part of a extended (about 4" x 2"), blue object with R = 23.3 +/- 0.2 and B = 23.8 +/- 0.4 which is consistent with the galaxy system reported independently by Fruchter et al. (GCN Circ. 1440). An identification chart is posted at www.iaa.es/~ajct/XRFs/xrf02042