TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4140 SUBJECT: GRB 051021: P200 Ks Observations DATE: 05/10/22 21:41:37 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko, Chris Conselice, Kevin Bundy, (Caltech), Derek B. Fox (Penn State), and Edo Berger (Carnegie), report on behalf of the Caltech-NRAO-Carnegie GRB collaboration: "We have imaged the field of GRB 051021 (Yoshida et al., GCN 4116) with the Wide Field Infrared Camera mounted on the Palomar 200" Hale Telescope. Our images consisted of 9 x 120 s exposures taken in the Ks filter at a mean epoch of approximately 22 October 5:24 UT (~ 16 hours after the burst). We find at best a marginal (< 3-sigma) detection at the location of the OT (Fox et al., GCN 4120). Our 3-sigma limiting magnitude, calculated with respect to several 2mass stars in the field, is approximately Ks > 19.0. We note that under the standard afterglow model, our result is inconsistent with the J-band detection reported by Haislip et. al (GCN 4127), and therefore calls into question the interpreration of GRB 051021 as a high redshift event."