TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3427 SUBJECT: XRF 050509C: REM NIR and Optical refined analysis DATE: 05/05/16 22:12:22 GMT FROM: Paolo D'Avanzo at INAF-OAB S. Piranomonte, P. D'Avanzo, L.A. Antonelli, S. Covino, D. Malesani, F.M. Zerbi, G. Chincarini, M. Rodono', G. Tosti, P. Conconi, G. Cutispoto, E. Molinari, L. Nicastro, E. Palazzi, V. Testa, F. Vitali, E. Meurs, P. Goldoni, on behalf of the REM/ROSS Team report: Following the detection of a candidate optical counterpart for XRF 050509c (HETE trigger #3751; GCN 3402), by Gorosabel et al. (GCN 3425) we re-analyzed our optical and NIR REM data (D'Avanzo et al GCN 3400). At 2.5 hours after the burst no object is found at the position of the candidate down to a limiting magnitude of R=19 and H=15.5 (3-sigma level). We note that our R limit is consistent with a power-law decay index of -1.2 (Gorosabel et al. GCN 3425). This message may be cited.