TITLE: GCN CIRCULAR NUMBER: 6993 SUBJECT: GRB071021 : CFHT Ks-band observation DATE: 07/10/25 06:55:17 GMT FROM: Yuji Urata at Saitama U Y. Urata (Saitama Univ.), K.Y. Huang (ASIAA), W.H. Ip (NCU), and L. Albert (CFHT/UH) on behalf of EAFON team: "We have observed the field of GRB 071021 (Sakamoto et al., GCN 6958) in Ks-band using the WIRCam instrument on the CFHT telescope. We marginally detected the afterglow (Castro-Tirado et al. GCNs 6968, 6971, Malesani et al. GCN 6972, Terada et al GCN 6976, Piranomonte et al. GCN 6985). The brightness derived from 2MASS stars is about Ks~21 at the mid time of the stacked image (2007-10-23-05:42). This result suggests that the NIR afterglow show shallow decay between October 22 and 23. Further analysis and observations are in progress." This message may be cited.