TITLE: GCN CIRCULAR NUMBER: 10928 SUBJECT: GRB 100615A: Additional Gemini/NIRI observations DATE: 10/07/02 22:58:46 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, J. S. Bloom, S. B. Cenko, and N. R. Butler (UC Berkeley) report: We again observed the field of GRB 100615A (D'Elia et al. 2010, GCN 10841) using NIRI on Gemini-North between 06:06 and 07:03 on 2010-06-24 UT, at moderately high airmass. We acquired 45 images of 60 seconds each in the K' filter, a significantly deeper integration than our previous observation (Cenko et al., GCN 10861). A faint object is detected slightly west of the latest online UVOT-enhanced XRT error circle, with an aperture magnitude of K' = 21.3 +/- 0.3 mag. However, the location of this object is not consistent with the improved X-ray localization provided by the Chandra observations (Butler et al., GCN 10915). A very faint possible source is visible at the Chandra location, but it is not statistically significant (1.5-sigma). The 3-sigma limit of the image is K' > 22.2 mag; forced photometry gives K' = 23.0 +/- 0.8 mag at this location. An image of the field is posted to: http://lyra.berkeley.edu/~dperley/100615a/100615a_niri.png