TITLE: GCN CIRCULAR NUMBER: 10692 SUBJECT: GRB 100424A: NIR Afterglow Confirmation DATE: 10/04/27 00:05:44 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, J. S. Bloom, D. A. Perley, A. N. Morgan, B. E. Cobb (UC Berkeley) and A. J. Levan (U. Warwick) report on behalf of a larger collaboration: We have obtained a second epoch of K-band imaging of the field of GRB 100424A (Hoversten et al., GCN 10667) with the Near InfraRed Imager and Spectrometer mounted on the 8 m Gemini North telescope. Observations began at 11:23 UT on 26 April 2010 (~ 43 hours after the burst). The previously identified candidate in the XRT error circle (Cenko et al., GCN 10682) has faded by 0.9 +/- 0.1 mag, confirming the object is indeed the NIR afterglow of GRB 100424A. Assuming negligible contribution from an underlying host galaxy, the inferred power-law decay index, alpha ~ 0.7, is relatively shallow. We wish to thank the staff at Gemini Observatory, in particular Kristin Chiboucas, for executing these observations.