TITLE: GCN CIRCULAR NUMBER: 24172 SUBJECT: LIGO/Virgo S190425z: SAGUARO follow-up observations DATE: 19/04/25 10:59:32 GMT FROM: Michael J. Lundquist at University of Arizona Michael J. Lundquist (UA), Kerry Paterson, Wen-fai Fong (Northwestern), David J. Sand (UA), Stefano Valenti (UC Davis), Sheng Yang (INAF-OAPd, UC Davis), Sam Wyatt (UA), Eric Christensen, Alex Gibbs, Frank Shelly (UA/LPL), Jennifer Andrews (UA) report: We initiated observations of 12 fields (each 2.26 x 2.26 deg^2) within the LVC localization region for the GW trigger S190425z (LVC Circ 24168) starting on 2019-04-25 9:01 UT. SAGUARO* uses the 1.5m Catalina Sky Survey telescope on Mt. Lemmon, AZ and its 5 deg^2 imager to tile the highest probability regions of the LVC localization that are accessible from southern Arizona in order to search for electromagnetic counterparts to gravitational wave events. The typical limiting magnitudes of single pointings are G~21 mag (calibrated to Gaia DR2). Below are the field centers observed. Any interesting transient candidates will be reported as soon as possible. RA DEC 244.2855 20.9792 245.7690 18.7708 247.2150 16.5625 242.7630 23.1875 240.4020 25.3958 237.9450 27.6042 235.4790 27.6042 237.9870 25.3958 240.3945 23.1875 247.9245 14.3541 249.3165 12.1458 235.3845 29.8125 *SAGUARO stands for Searches After Gravitational-waves Using ARizona's Observatories. It is a partnership between the University of Arizona and Northwestern University.