TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1321 SUBJECT: GRB020331 NIR observation at KPNO (re-submission) DATE: 02/04/02 02:50:44 GMT FROM: Atsumasa Yoshida at Inst.Phys/Chem Research In the previous submission (GCN1320), there was an error in the subject-line. This is the revised version but contains the same information about the obseration as in GCN1320. ------------------------------------------------------- K. Ohta (Kyoto Univ.) and M. Akiyama (Subaru) report: We have imaged the central region of the error circle of GRB 020331 with the SQIID equipped to KPNO 2.1m telescope. The field is centered on 13h16m22.7s and -17d55'23" (J2000) with a field of view of about 5'x5'. The J-, H-, and K-band images were taken simultaneously at 7:06 (Apr 1st) (UT). A total integration time is 15min for each band. We have found the following two NIR objects that are not seen in the Digitized Sky Survey, APM catalog, and 2MASS images. #1 13h16m29.5s -17d55'08" (J2000), J=17.7, H not measurable, K=16.8 #2 13h16m23.2s -17d56'11" (J2000), J=17.6, H=17.2, K=16.8 Accuracy of the coordinates is about 0.5". Photometry was roughly made using 2MASS objects exposed in the same frame; accuracy seems to be less than 0.1 mag (J-band), 0.3 mag (H-band), and 0.5 mag (K-band). There is a possibility that these objects are not seen in the POSS merely because they are red objects. If one of them will fade, it should be a candidate of the afterglow of the GRB. Further NIR observations are desirable. This message may be cited.