TITLE:   GCN CIRCULAR
NUMBER:  12819
SUBJECT: GRB 120106A: MITSuME Okayama Ks-band upper limit
DATE:    12/01/07 12:15:37 GMT
FROM:    Kenshi Yanagisawa at OAO/NAOJ  <yanagi@oao.nao.ac.jp>

Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Kiichi Okita
(OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U),
and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME
collaboration:

We observed the field of GRB120106A (Immler et al., GCNC 12810) in
Ks-band with a wide-field NIR camera at Okayama  Astrophysical
Observatory (Japan). The camera has an effective aperture of 0.91m.

Observations started from 15:19 UT on 5th January, 1.05 hours after
the BAT trigger, to 16:20 UT.  The total exposure of 49 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., GCNC 12813) down to limiting
magnitude of  Ks= 15.6(Vega, S/N=3). The photometric calibration was
made against 2MASS field stars.

T0+[min]    MID-UT     T-EXP[min]      Ks
---------------------------------------------------
  +93.6     15:50         49.0       >15.6 (S/N=3)
---------------------------------------------------
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]