TITLE: GCN CIRCULAR NUMBER: 24368 SUBJECT: LIGO/Virgo S190426c: Gaia19boq 0.6m BOOTES-5/JGT, 1.5m OSN and 10.4m GTC observations DATE: 19/05/02 14:38:17 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC R. Sanchez-Ramirez (INAF-IAPS), A. F. Valeev and V. V. Sokolov (SAO-RAS), Y.-D. Hu, A. J. Castro-Tirado, X.-Y. Li, A. Ayala, E. Fernandez-Garcia and F. J. Aceituno (IAA-CSIC), I. Carrasco, A. Castellon and C. Perez del Pulgar (UMA), D. Hiriart and W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU), A. Garcia and S. Geier (GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report: Following the detection of Gaia19boq (Kostrzewa-Rutkowska et al., GCN 24344) within the error area of the GW event S190426c (LVC, GCN 24237), we observed the target with the 1.5m telescope at the Observatorio de Sierra Nevada (Spain) in the BVI-bands, starting on May 1, 04:07 UT. Complementary images I ugriZ were taken starting on May 1, 11:41 UT at the 0.6m BOOTES-5/JGT in Observatorio Nacional de San Pedro Martir (Mexico). In addition, an optical spectrum (900s) covering the range 3700-7500 A was obtained with the 10.4m GTC telescope equipped with OSIRIS in La Palma (Spain) starting on May 1, 04:07 UT. The Gaia19boq spectrum reveals strong Balmer lines in absorption, with the exception of a very weak H-alpha showing a P Cyg profile. All lines are redshifted ~400 km/s. Therefore we conclude that Gaia19boq is found to be a CVN star in outburst in our Galaxy and therefore unrelated to the GW event S190426c. We acknowledge the excellent support from the GTC staff.