GCN Circular 1227
VLT observations of GRB 020124: The fading optical/near-infrared afterglow J. Hjorth (U. Copenhagen), J. Gorosabel (DSRI, Copenhagen), and J. Fynbo (ESO) report on behalf of the Gamma-Ray Afterglow Collaboration at ESO (GRACE): We have obtained optical and near-infrared images of the possible optical afterglow (Price et al., GCN #1221; Gorosabel et al., GCN #1224; Bloom, GCN #1225) of GRB 020124 (Ricker et al., GCN #1220) with ESO's VLT. 30-min Ks-band exposures were obtained with ISAAC/Antu on Jan 26.20 (seeing FWHM = 0.50") and Jan 27.20 (FWHM = 0.44") 2002 UT; a 15-min R-band image (FWHM = 0.66") was obtained with FORS1/Melipal on Jan 27.28 2002 UT. The source identified by Gorosabel et al. in NOT R-band images obtained on Jan 26.06 (cf. GCN #1224) has clearly faded in the FORS1 R-band image. The source is also detected in the ISAAC Ks data and is fading between the two epochs of observation. These findings strongly suggest that the source identified by Price et al. is indeed the optical/NIR afterglow of GRB 020124. A more detailed analysis of the data is in progress. Meanwhile, we have posted images showing the decaying Ks-band source at http://www.astro.ku.dk/~jens/GRB020124_ISAAC_Ks_GRACE.gif We appreciate the kind and efficient assistance of the ESO staff at Paranal Observatory (Nancy Ageorges, Thomas Szeifert and Riccardo Scarpa) in conducting the reported service mode observations.