[vsnet-grb-info 27700] GRB 210411C: BOOTES-4/MET optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29803
SUBJECT: GRB 210411C: BOOTES-4/MET optical upper limit
DATE:    21/04/11 23:14:20 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072 at hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, M. A. Castro Tirado (IAA-CSIC), C. Perez del Pulgar (Univ. de Malaga), S. Guziy (Univ. of Nikolaev) and D. R. Xiong, Y. F. Fan, J. M. Bai, C. J. Wang, Y. X. Xin, X. H. Zhao (Yunnan Observatories of CAS) on behalf of a larger collaboration, report:

Following the detection of GRB 210406A by Swift (Sbarrato et al. GCNC 29794), follow-up observations at the 0.6m BOOTES-4/MET robotic telescope in Lijiang Astronomical Observatory (China) were performed starting on Apr 11, 20:52 UT (~5.8 hr after trigger) at high airmass. No new source is detected down to 19.6 mag at the optical afterglow position reported by UVOT (Sbarrato et al. GCNC 29794) and the 1.0m LCO in Siding Spring (Strausbaugh et al. GCNC 29802) in our co-added image (25x60 s, clear filter) confirming the fading in the optical range.

We thank the staff at Lijiang observatory for their excellent support.