TITLE: GCN CIRCULAR NUMBER: 16096 SUBJECT: GRB 140408A: 1.5m OSN optical upper limit DATE: 14/04/10 18:34:22 GMT FROM: Soomin Jeong at CSIC S. Jeong, S. R. Oates, J. C. Tello, J. Gorosabel, A. Sota and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: "Following the detection of GRB140408A by Swift (D'Elia et al., GCNC 16082), we observed the field of GRB 140408A with the 1.5 m OSN telescope at Observatorio de Sierra Nevada in the R and I-bands. The observation started on Apr 9, 04:01:16 UT (i.e. ~0.62 d post burst). No optical afterglow is found at the position of the optical candidate reported by Varela et al. (GCNC 16089) in the median combined images (6 x 300s) down to 21.7 mag (I band) and 22.5 mag (R band) (3-sigma upper limits, with all magnitudes in Vega system and no correction for the Galaxy reddening)."