GCN Circular 19944
I.A.Steele (LJMU), C. Guidorzi (U. Ferrara), C. G. Mundell (Bath), A. Gomboc (U. Nova Gorica), J. Japelj (INAF-OAT) report on behalf of a larger collaboration. We report optical spectroscopy of the MASTER optical transient (GCN 19938, 19939, 19941) which is a possible optical counterpart to the FERMI GBM trigger 496473540 (GRB160925A). The optical transient has the ID MASTER OT J222817.90-145657.4. A low resolution (R~350) optical (400-800nm) spectrum was obtained using the SPRAT spectrograph of the Liverpool Telescope (La Palma) on 26-09-16 at 21:25:49 UT. The 300 second exposure shows a strong, blue continuum with clear H-beta and H-gamma absorption lines at zero redshift. H-alpha is not present either in emission or absorption (implying a degree of H-alpha emission). The spectrum is consistent with a dwarf nova during outburst and therefore not likely to be associated with the Fermi trigger.