TITLE: GCN CIRCULAR NUMBER: 27211 SUBJECT: LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations. DATE: 20/02/25 21:25:28 GMT FROM: Fiore De Luise at INAF-Osservatorio Astro. d'Abruzzo F. De Luise, P. Tedesco, N. Napoleone (INAF- OAAb), A. Rossi (INAF-OAS), M. Dolci, G. Valentini, M. Cantiello, A. Di Cianno, A. Valentini, L.P. Pacinelli (INAF- OAAb), M. Fiaschi (MFC Elettronica), G. Greco (Univ. Urbino), E. Cappellaro (INAF-OA Pd), P. D'Avanzo(INAF- OABr), A. Grado (INAF-OA Capodimonte), and E. Brocato (INAF- OAAb and OAR), report on behalf of GRAWITA: We carried out observations of the LIGO/Virgo trigger GW S200224ca (GCN Circ. #27184) using the INAF-OAAb 0.9m Schmidt Telescope of the INAF - Astronomical Observatory of Abruzzo located at 2150 meters o.s.l. at Campo Imperatore (Italy) and equipped with a 4096x4096 CCD covering a field of view of 1.15��1.15 square degrees. Due to weather conditions, only three pointings were made covering an area of nearly 4 square degrees; a containment probability of ~ 8 % of the 50% credible region was captured. The pointing sequence was generated using the GWsky script (G. Greco, https://github.com/ggreco77/GWsky), starting from the high probability region of the bayestar skymap and taking into account the airmass and relative density of nearby galaxies at the distance of 1585 +/- 331 Mpc. The total exposure time for each image was 3x180 sec. The observations were taken with the r-Sloan band on 2020-02-24 starting at 23:47:37.0 UT, about one hour after the GW detection (i.e. 2020-02-24 22:22:34.406 UTC). The estimated limiting magnitude in r-Sloan is about 21.5 mag. Hereafter the log of the observations. | RA (J2000) | Dec (J2000) | UT time | filter | exposure time| | 11:43:50.29 | -07:49:10 | 2020-02-24T23:47:37.0 | r-sloan | 3x180 sec | | 11:35:44.35 | -07:49:10 | 2020-02-25T00:04:09.6 | r-sloan | 3x180 sec | | 11:39:47.98 | -07:49:35 | 2020-02-25T00:20:44.8 | r-sloan | 3x180 sec | The analysis of images is ongoing. -------------------------------------------- De Luise Fiore, PhD INAF - Osservatorio Astronomico d'Abruzzo Via Mentore Maggini, s.n.c. 64100 - TERAMO Tel +39-0861-439712 Fax +39-0861-439740 --------------------------------------------