TITLE: GCN CIRCULAR NUMBER: 24064 SUBJECT: LIGO-Virgo GW S190408an: J-GEM optical/NIR follow-up observations DATE: 19/04/08 20:58:09 GMT FROM: Katsuhiro L. Murata at Nagoya U Murata, K. L. (Tokyo Tech), Sasada, M., Nakaoka, T. (Hiroshima U.), Morokuma, T. (U. of Tokyo), and Utsumi, Y. (Stanford U./SLAC), on behalf of J-GEM collaboration Right after receiving the first gravitational wave alert, S190408an, in the observing run 3 (O3), we conducted optical and near-infrared imaging observations of 7 nearby galaxies (see a table below) within the probability skymap of S190408an with - 50 cm MITSuME telescope at Akeno Observatory using a 3 color imager in g’, Rc, Ic - 50 cm MITSuME telescope at Okayama Astrophysical Observatory using a 3 color imager in g’, Rc, Ic - Kanata 150 cm telescope at Higashi-Hiroshima Observatory using HONIR -- a 2 color imager in Rc and H (Sakimoto et al. 2012, SPIE, 8846, 884673; Akitaya et al. 2014, 9147, 91474O; Ui et al. 2014, 9147, 91476C) We also performed blind imaging survey over 260 deg2 using Tomo-e Gozen camera on the 105-cm Kiso Schmidt telescope which is a very wide-field (20 deg2 field-of-view) optical CMOS imager (Sako et al. 2018, SPIE, 10702, 107020J). Data reduction is in progress. name RA Dec GL221849+205045 334.7061 20.846 GL231817+515551 349.572 51.9309 GL225419+384152 343.5806 38.6978 GL225746+424819 344.4403 42.8053 GL222235+224327 35.6449 22.7242 GL222437+203049 336.153 20.5135 GL184632-384819 281.6345 -38.8053 These observations were done in the framework of J-GEM collaboration (Morokuma et al. 2016, PASJ, 68, 9L).