P. D'Avanzo, A. Melandri (INAF-OAB), S. Piranomonte (INAF-OAR), E. Palazzi (INAF-IAFS Bo), M. Branchesi (Urbino University/INFN Pisa), G.Greco (Urbino University/INFN Firenze), E. Brocato (INAF-OAR), S. Campana (INAF-OAB), E. Cappellaro (INAF-OAPd), S. Covino (INAF-OAB), F. Getman (INAF-OAC), A. Grado (INAF-OAC), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), L. Nicastro (INAF-IASF Bo), E. Pian (SNS-Pisa), L. Pulone (INAF-OAR), G. Stratta (Urbino University/INFN Firenze), V. Testa (INAF-OAR), A. Fiorenzano, W. Boschin, D. Carosati (INAF-TNG), on behalf of the INAF Gravitational Astronomy group report:
We observed the optical transient reported by Rabinowitz et al. (LSQ15bjb; LIGO/Virgo Circular #18473), located in the skymap of the avanced LIGO and Virgo trigger G194575 (Singer et al., LIGO/Virgo Circular #18442). The observations were carried out with the 3.6m Italian TNG telescope, located in Canary Islands (Spain), equipped with the DOLORES camera in both imaging and spectroscopic mode on 2015 Oct 26.
The optical transient is clearly detected. At a mean time of 21:24:10 UT we measure a magnitude of i' = 17.48 +/- 0.05 (AB), calibrated with respect of the SDSS DR10.
Spectroscopic analysis is ongoing