TITLE: GCN CIRCULAR NUMBER: 20784 SUBJECT: LIGO/Virgo G275404: A near-infrared transient in the error circle of AGL J1914+1043 DATE: 17/03/01 09:17:28 GMT FROM: Michitoshi Yoshida at J-GEM Yoshida, M., Utsumi, Y., Nakaoka, T., Abe, T., Nagashima, H., Kawabata, K. S., Kawabata, M., Shiki, K. (Hiroshima U.), Ohsawa, R. and Sako, S. (U. of Tokyo) on behalf of J-GEM collaboration We performed near-infared H-band observations of nearby galaxies in the error circle of the gamma-ray transient candidate found in the AGILE-GRID data, AGL J1914+1043 (Tavani et al. GCN 20754), which is located at the edge of the skymap of G275404 (GCN 20738) with 1.5m Kanata telescope on UT 2017-02-27. The instrument used was an optical near-infrared simultaneous camera HONIR. We found a bright near-infrared transient in the observed field of GL191032+075314. The data was taken at 20:32UT on 2017-02-27. The H-band AB magnitude of the source was 16.3 +- 0.02. The location of the source is RA=19:10:31.46, DEC=+07:53:52.0 . We also conducted an I-band observation for this area simultaneously. No transient source was detected with the 5-sigma I-band limiting magnitude of 19.6. There is no bright counterpart in 2MASS H-band data, but a point source (SSTGLMC G042.1312-00.6118; in GLIMPSE I Spring '07 Catalog) is clearly seen at the same position in 3.6 um data taken by Spitzer GLIMPSE survey. The observation log with 5-sigma limiting magnitudes is shown below. Telescope: Kanata 1.5m telescope ------------------------------------------------------ galaxy RA DEC UT H ------------------------------------------------------ GL191032+075314 287.6351 7.8871 2017/2/27-20:32 18.7 GL192215+140356 290.561 14.0655 2017/2/27-21:11 17.5 GL191327+105427 288.3622 10.9076 2017/2/27-20:52 18.5 GL191032+075314 287.6351 7.8871 2017/2/27-20:32 18.3 GL190530+100857 286.3748 10.1491 2017/2/27-20:12 18.1 GL190618+125620 286.5759 12.9388 2017/2/27-19:53 18.2 GL190415+125637 286.0637 12.9437 2017/2/27-19:33 17.8 GL185836+113738 284.6512 11.6271 2017/2/27-19:13 17.9 ------------------------------------------------------