TITLE: GCN CIRCULAR NUMBER: 10682 SUBJECT: GRB 100424A: Gemini/NIRI Candidate Afterglow DATE: 10/04/25 09:47:55 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, J. S. Bloom, A. N. Morgan, and B. E. Cobb (UC Berkeley) report on behalf of a larger collaboration: We have imaged 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 were taken in the J and K filters beginning at 6:28 UT on 25 April 2010 (~ 14 hours after the burst). At the edge of the refined XRT error circle (Evans et al., GCN 10669) we identify a faint point source in both filters. Referencing both the astrometry and photometry to the 2MASS source 13574681+0131477, we measure a position (J2000.0) of RA: 13:57:47.43 Dec: +01:32:18.9 and approximate magnitudes of K = 19.9, J = 22.1 (both Vega magnitudes). The J-K color indicates a red afterglow, though does not necessarily require a high-redshift origin (e.g., Levan et al., GCN 10672). No other objects are detected inside the XRT error circle. Without evidence for variability, we cannot definitively confirm if this source is the afterglow of GRB 100424A. Further observations are planned to search for fading. We wish to thank the staff at Gemini Observatory, in particular Kristin Chiboucas, for promptly executing these observations.