TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1327 SUBJECT: GRB 020405, U-band observations DATE: 02/04/06 04:53:03 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia GRB 020405, U-band observations --------------------------- A. J. Castro-Tirado, J. Gorosabel (Instituto de Astrofísica de Andalucía, IAA-CSIC, Granada), T. Augusteijn (Isaac Newton Group of Telescopes) and José María Castro Cerón (ROA,San Fernando) report: We have observed the central region of the GRB 020405 error box (Hurley et al., GCN Circ. 1325) with the Prime Focus Camera at the 4.2-m William HerschelTelescope at the ORM in La Palma, providing a 16'.2 square field of view. A comparison of the U- and R-band images obtained on Apr 6.104-6.122 UT reveals an extremely blue object at the position of the optical candidate proposed by Price et al. (GCN Circ. 1326) thus supporting the relationship with the GRB. This U-band detection would imply that the redshift is < 2.1 . This message can be cited. [GCN OPS NOTE (20jul02): The affiliation for JMCC was changed from "IAA-CSIC and ROA, San Fernando" to "ROA, San Fernando".]