GCN Circular 3389
GRB 050509A: Optical observations J. P. U. Fynbo, B. L. Jensen, J. Hjorth, P. Jakobsson, J. M. Castro Cer�n, H. Pedersen, D. Watson (Niels Bohr Institute), J. N�r�nen (Nordic Optical Telescope) report: "Using ALFOSC on the 2.56m Nordic Optical Telescope we have obtained I-band imaging of the XRT error circle for GRB 050509A (Swift trigger 118707, GCN 3379, 3380) at two epochs starting ~20 min and ~2.5 hr after the GRB trigger. In the XRT error-circle we detect several sources. One source is less than 2" from the centre of the XRT error circle and not seen in the DSS-II (red). The position of this source is: RA(2000) = 20:42:19.60, Dec(2000) = +54:04:17.8 The source is fainter than the sensitivity of the DSS-II red image and has an estimated magnitude of I = 21.7 (not corrected for a galactic extinction of A_I = 1.15 mag). The source does not vary significantly between the two epochs. An image of the field is shown at: http://www.astro.ku.dk/~brian_j/grb/grb050509A/ "