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GCN Circular 12589

GRB 111123A: GMG optical observation
2011-11-24T02:23:25Z (13 years ago)
Dong Xu at Weizmann Inst <>
D. Xu (WIS), X.-H. Zhao, J.-R. Mao, J.-M. Bai (YNAO) report:

We observed the field of GRB 111123A (Stamatikos et al., GCN 12587)
with the 2.4m Gao-Mei-Gu (GMG) telescope equipped with YFOSC, and
obtained 3x600s R-band and 3x600s I-band images, starting at 21:00:56
UT on Nov. 23rd (i.e., 2.793 hrs after the burst).

Within the XRT SPER error circle (, no
optical source was detected in the stacked I-band image, and a weak
and compact source was found in the stacked R-band image at

RA(J2000)  =  10:19:23.10
Dec(J2000) = -20:38:41.72

with an uncertainty of ~1" in each coordinate. We caution that the
above source may be ascribed to background fluctuation. In this sense,
we derive R>~23.7 mag, calibrated with the #0693-0243590 star
(R1=17.95 and R2=17.60) in the USNO B1 catalog.

Deeper and NIR observations are encouraged.

We are grateful to Chuan-Jun Wang, De-Qing Wang, and Yan-Dong Lang for
performing these observations.

[GCN OPS NOTE(24nov11): Per author's request, Mao was added to the author list.]
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