TITLE: GCN CIRCULAR NUMBER: 25372 SUBJECT: LIGO/Virgo S190814bv: GROND imaging of candidate galaxies DATE: 19/08/16 18:40:57 GMT FROM: Ting-Wan Chen at MPE T.-W. Chen (MPE), A. Nicuesa Guelbenzu (TLS Tautenburg), M. Fraser (UCD), J. Bolmer (MPE), T. Schweyer (MPE), A. Rau (MPE), S. Klose (TLS Tautenburg), L Salmon (UCD), S. J. Smartt (QUB), A. J. Levan (Radboud Univ), and Paolo D'Avanzo (INAF-OAB) report for a larger collaboration: We observed 36 galaxies within the 90% error volume of S190814bv (LVC GCN 25324) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations were obtained on 15 August 2019 between 04:39 and 10:16 UT, 7.5 hours after the GW event. Galaxies were selected from the HOGWARTS code (https://gwtool.watchertelescope.ie/). For each galaxy we obtained on avarage 2.1 min in the optical bands and 3.9 min in the NIR bands. Observations were performed under seeing conditions varying from 1".0 to 2".3 with an average seeing of 1".4, and at an airmass ranging from 1.0 to 1.4 with an average airmass of 1.1. According to these conditions, the typical 3-sigma detection limit in the r' band is 21.3 mag and 19.8 mag in J (all in the AB system). Visual inspection of the r' and J-band images shows no apparent candidates in any of the images in comparison to archival imaging from Pan-STARRS, DSS and WISE. Although we caution that fainter candidates close to their hosts could be missed in such an inspection. The locations of the galaxies observed are --------------------------------------------------- No. RA (J2000) Dec (J2000) 1 10.676272 -21.774082 2 10.242757 -22.083128 3 13.192388 -22.975018 4 11.781363 -24.370647 5 23.594837 -32.835316 6 23.018082 -33.802876 7 12.180364 -23.561686 8 13.806392 -26.321253 9 10.666405 -21.800196 10 23.089487 -31.092321 11 12.364808 -26.538301 12 24.334146 -33.330853 13 14.254662 -23.837297 14 21.229847 -30.621069 15 10.862282 -22.189581 16 13.704722 -26.371256 17 22.342892 -32.849354 18 20.766964 -31.095718 19 11.442945 -25.920193 20 9.807239 -22.102215 21 10.639115 -22.866308 22 23.877426 -32.970612 23 12.25617 -23.811317 24 22.93853 -32.415623 25 12.441799 -26.443037 26 12.120861 -22.147444 27 9.920177 -22.196348 28 11.870618 -25.440655 29 10.91611 -21.659298 30 22.549915 -32.903667 31 11.472051 -23.772461 32 11.543399 -24.650192 33 12.666141 -26.813395 34 12.320091 -26.219179 35 13.804421 -24.044033 36 22.145348 -32.296467 --------------------------------------------------- Note: we re-observed those galaxies (numbers 3, 6, 8, 15, 23 and 29) on 16 August 2019 with GROND, in order to obtain one magnitude deeper images to confirm some possible marginally detected sources taken on 15 August. None of these sources were still detected or convincing though, and we hence do not consider them as genuine sources. We acknowledge excellent help in obtaining these data from Angela Hempel and RĂ©gis Lachaume on La Silla.