TITLE: GCN CIRCULAR NUMBER: 24119 SUBJECT: LIGO/Virgo S190412m: Palomar Gattini-IR Wide-field Infrared Follow-up DATE: 19/04/13 16:05:02 GMT FROM: Kishalay De at Caltech, GROWTH K. De (Caltech), S. M. Adams (Caltech), I. Andreoni (Caltech), S. Anand (Caltech), M. Hankins (Caltech), L. Singer (NASA GSFC), M. Coughlin (Caltech), T. Ahumada (UMD), M. M. Kasliwal (Caltech), A. Moore (ANU), J. Soon (ANU), M. Ashley (UNSW), T. Travouillon (ANU) report on behalf of the Palomar Gattini-IR team and the larger GROWTH (Global Relay of Observatories Watching Transients Happen) collaboration We report wide-field near-infrared follow-up observations of the localization region of the BBH gravitational wave event S190412m (GCN 24098) by the Palomar Gattini-IR survey (Moore and Kasliwal 2019). Gattini-IR is a newly commissioned near-IR camera with a field of view of 25 square degrees mounted on a robotic 30 cm telescope at Palomar observatory. Starting 15 min after the BBH merger notice, we mapped the localization in J-band. We imaged a total of 430 sq. deg. for four epochs between 2019-04-12 06:45 UT and 2019-04-12 10:45 UT, spread over 18 field tiles in the localization region. The tiling was optimally determined and triggered using the GROWTH Target of Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al. 2019b). The observations cover a total of 95 % of the probability region. Each of 4 epochs consisted of a sequence of 8 dithers of 8 second exposures each on the field, which were processed and stacked with the Palomar Gattini-IR data reduction pipeline. No viable counterparts were identified. The typical limiting magnitude of each stacked epoch (64 second exposure time) was between 15.5 - 16 AB mag in J-band.