[AAVSO-HEN] GRB 090401B: Xinglong TNT optical Upper Limit

[grb at aavso.org]

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TITLE:   GCN CIRCULAR
NUMBER:  9082
SUBJECT: GRB 090401B: Xinglong TNT optical Upper Limit
DATE:    09/04/03 09:17:29 GMT
FROM:    L.P. Xin at NAOC  <xlp at bao.ac.cn>

S.M. Hu, L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng and J.Y. Hu on behalf of EAFON report:

We have observed GRB 090401B (Schady et al., GCN
9066; Schady & Oates, GCN 9067, GCN 9074)
with Xinglong TNT telescope from Apr.1, 11:25:22(UT),
3.37 hr after the burst. After combined 9*300s R
band images, no new source was found in our combined
image. The 3 sigma upper limits was obtained
to be R=19.9 mag at the mean time of 2.71 hr after 
the trigger, with the calibration to USNO-B1.0 R2 magnitude.

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