[vsnet-grb-info 20559] GRB 180418A: 1.5m OSN optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22657
SUBJECT: GRB 180418A: 1.5m OSN optical observations
DATE:    18/04/18 20:57:12 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct at iaa.es>

A. Sota, Y. Hu, J. C. Tello, I. Carrasco and A. J. Castro-Tirado 
(IAA-CSIC), on behalf of a larger collaboration, report: "Following the 
detection of GRB 180418A with the Neil Gehrels Swift Observatory (D'Elia 
et al. GCNC 22646), I-band observations at the 1.5m telescope at 
Observatorio de Sierra Nevada (Granada, Spain) have been gathered on Apr 
18 starting at 19:49 UT (13 hr post burst). At the position of the 
optical afterglow (Zheng and Filippenko, GCNC 22647; Guidorzi et al., 
GCNC 22648; Troja et al., GCNC 22652), no counterpart is detected down 
to I = 21.0 in the coadded image (5x300s)."