[vsnet-grb-info 17119] GRB 151022A: MITSuME Okayama Ks-band upper-limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18440
SUBJECT: GRB 151022A: MITSuME Okayama Ks-band upper-limit
DATE:    15/10/22 15:51:57 GMT
FROM:    Kenshi Yanagisawa at OAO/NAOJ  <yanagi at oao.nao.ac.jp>

K. Yanagisawa, D. Kuroda, Y. Shimizu, H. Izumiura(OAO/NAOJ),
M. Yoshida (Hiroshima), K. Ohta(Kyoto) and N. Kawai(Tokyo Tech.)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 151022A (D'Avanzo et al., GCN 18436)
in Ks-band with a wide-field near infrared imager at Okayama
Astrophysical Observatory (Japan).  The imager has effective
aperture of 0.91 m.

Observations started from 14:13 UT on 22th October, 0.12h after
the BAT trigger, to 14:56 UT. The total exposure of 17.0 min
was successfully obtained.

In our co-add image, we did not find any new point source within
the enhanced XRT error circle (Evans et al., GCN 18438) down to limiting
magnitude of Ks=14.8 (Vega, S/N=10). The photometric calibration was
made against 2MASS field stars.

T0+[sec]    MID-UT     T-EXP[sec]      Ks
---------------------------------------------------
 +1,721     14:35      1,020.0         >14.8
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]