TITLE: GCN CIRCULAR NUMBER: 24299 SUBJECT: LIGO/Virgo S190426c: J-GEM optical/NIR follow-up observations DATE: 19/04/27 20:03:16 GMT FROM: Yuu Niino at University of Tokyo Niino, Y., Morokuma, T., Ohsawa, R., Sako, S., Shikauchi, M. (U. of Tokyo), Yanagisawa, K. (NAOJ), Takagi K., Nakaoka, T., Sasada, M.(Hiroshima U.), Saito, T. (Nishi-Harima Astronomical observatory), Itoh, R. (Bisei Astronomical Observatory), Ohta, K. (Kyoto U.), Utsumi, Y. (Stanford U./SLAC), Sekiguchi, Y. (Toho U.), Tominaga, N. (Konan U.), on behalf of J-GEM collaboration We report our optical and near-infrared imaging observations for the gravitational wave event S190426c that has a non-zero probability to be a NS-BH merger. We performed 180 deg2 wide-field imaging survey, using the Tomo-e Gozen camera on the 105-cm Kiso Schmidt telescope, a very wide-field (20 deg2 field-of-view) optical CMOS imager (Sako et al. 2018, SPIE, 10702, 107020J). The observations started about 19 hours after the GW detection. A typical limiting magnitude is about 20 mag (no filter). Data reduction is in progress. We also performed galaxy-targeted observations for 33 galaxies (see the table below) selected from the GLADE catalog (Dalya et al. 2016) in the probability skymap of S190426c using the following telescopes/instruments. - 91 cm Okayama Astrophysical Observatory NIR Wide‐Field Camera (OAOWFC, J-band, Yanagisawa, K., et al. 2014, Proc. SPIE, 9147, 91476D, Yanagisawa, K., et al. 2016, Proc. SPIE, 9908, 99085D) - 150 cm Kanata telescope at Higashi-Hiroshima Observatory and HONIR, a 2 color imager in Rc and H bands (Akitaya et al. 2014, 9147, 91474O) - 200 cm Nayuta telescope at Nishi-Harima Astronomical Observatory and Nishiharima Infrared Camera (NIC) We found no apparent transient objects in these galaxies to the 5 sigma limiting magnitudes listed below. galid ra dec J H R NoFilt K obsid GL204400+531432 310.9979 53.2423 17.08 -- -- -- -- OAOWFC GL221519+843451 333.8273 84.581 -- -- -- 99.99 -- Kiso Schmidt GL232822+852913 352.0922 85.4869 -- 99.99 99.99 -- -- Kanata-HONIR GL233253+853017 353.222 85.5048 -- 15.35 17.65 -- -- Kanata-HONIR GL002228+854955 5.617 85.8321 17.33 17.24 -- -- 99.99 Nayuta GL011607+845904 19.0275 84.9843 -- -- -- -- 99.99 Nayuta GL235357+842524 358.4862 84.4233 -- -- -- 99.99 -- Kiso Schmidt GL233600+852510 353.9992 85.4196 -- -- 17.65 -- -- Kanata-HONIR GL235923+834710 359.8466 83.7861 -- 99.99 -- -- -- Kanata-HONIR GL223741+844405 339.4209 84.7347 -- -- -- 99.99 -- Kiso Schmidt GL215853+832141 329.7229 83.3614 -- -- -- 99.99 -- Kiso Schmidt GL214359+841507 325.9938 84.2519 -- -- -- 18.29 -- Kiso Schmidt GL222416+864727 336.0676 86.7909 -- -- -- 99.99 -- Kiso Schmidt GL205538+853151 313.9084 85.5307 -- -- -- 99.99 -- Kiso Schmidt GL233600+852604 353.9975 85.4346 -- 15.35 17.65 -- -- Kanata-HONIR GL201328+463031 303.3651 46.5087 17.57 -- -- -- -- OAOWFC GL221751+832357 334.4629 83.3993 -- -- -- 99.99 -- Kiso Schmidt GL205927+845437 314.8623 84.9103 -- -- -- 99.99 -- Kiso Schmidt GL224440+824209 341.1686 82.7026 -- -- -- 18.95 -- Kiso Schmidt GL225030+824531 342.6235 82.7586 -- -- -- 19.00 -- Kiso Schmidt GL201355+462212 303.4775 46.3701 17.57 -- -- -- -- OAOWFC GL235428+842518 358.6179 84.4217 -- -- -- 99.99 -- Kiso Schmidt GL223827+872835 339.6125 87.4764 -- -- -- 17.11 -- Kiso Schmidt GL180154+865139 270.4751 86.8608 -- -- -- 17.75 -- Kiso Schmidt GL233512+852612 353.7982 85.4366 -- 15.35 17.65 -- -- Kanata-HONIR GL215728+854334 329.3673 85.7262 -- -- -- 15.99 -- Kiso Schmidt GL194045+874800 295.188 87.7998 -- -- -- 17.69 -- Kiso Schmidt GL150924+865350 227.3519 86.8972 -- -- -- 99.99 -- Kiso Schmidt GL211419+871821 318.5808 87.3058 -- -- -- 17.59 -- Kiso Schmidt GL204129+862633 310.3714 86.4425 -- -- -- 99.99 -- Kiso Schmidt GL233452+852734 353.7174 85.4593 -- 15.35 17.65 -- -- Kanata-HONIR GL173106+875633 262.7764 87.9426 -- -- -- 18.29 -- Kiso Schmidt GL212800+853445 321.9959 85.5793 -- -- -- 18.29 -- Kiso Schmidt Note that a limiting mag = 99.99 is due to failure in our real-time data analysis.