TITLE: GCN CIRCULAR NUMBER: 30933 SUBJECT: IceCube-20210922A: No optical counterparts found by MITSuME observations DATE: 21/10/12 10:08:01 GMT FROM: Masafumi Niwano at Tokyo Institute of Tech <niwano@hp.phys.titech.ac.jp> M. Niwano, R. Hosokawa, K. L. Murata, N. Kawai (Tokyo Tech), R. Itoh (Bisei Astronomical Observatory), Y. Utsumi (SLAC) We report optical imaging observations for finding an optical counterpart to IceCube event IC135736_30987826. We started our observations from 2021-09-23 15:13 UT (MJD=59480.63) and ended at 2021-10-04 18:55 UT (MJD=59491.79). We performed galaxy-targeted observations for 69 galaxies (see the table below) selected from the BROS Blazar catalog (Itoh et al. 2021) and the GLADE galaxy catalog (Dalya et al. 2018) in the probability skymap of IC135736_30987826 using MITSuME-Akeno: 50 cm MITSuME telescope at Akeno Observatory and a 3 color imager (g, Rc, Ic). We found no apparent transient objects in these galaxies to 5 sigma limiting magnitudes in the AB system listed below. galid ra(deg) dec(deg) dist(Mpc) g Rc Ic BROS_J0401.5-0422 60.381813 -4.366799 9999.0 16.4 17.4 17.1 BROS_J0400.4-0425 60.113051 -4.417749 9999.0 17.3 17.4 17.2 BROS_J0359.1-0423 59.795055 -4.391522 9999.0 18.0 17.6 17.1 BROS_J0402.9-0405 60.741136 -4.096962 9999.0 18.4 18.3 17.8 BROS_J0358.9-0408 59.741407 -4.142756 9999.0 18.0 17.6 17.1 BROS_J0402.5-0339 60.637954 -3.663903 9999.0 16.4 16.3 16.0 BROS_J0357.9-0443 59.481121 -4.72601 9999.0 18.2 18.1 17.4 BROS_J0402.4-0322 60.622619 -3.381488 9999.0 18.1 18.2 17.8 BROS_J0407.4-0405 61.866362 -4.085092 9999.0 17.8 17.6 16.9 BROS_J0407.5-0420 61.886763 -4.33758 9999.0 17.8 17.5 16.9 BROS_J0356.9-0436 59.229717 -4.60147 9999.0 18.2 18.0 17.4 BROS_J0400.3-0309 60.075952 -3.155558 9999.0 18.2 18.1 17.5 BROS_J0400.5-0308 60.125425 -3.140577 9999.0 18.2 18.0 17.5 BROS_J0359.3-0310 59.846607 -3.175879 9999.0 18.2 18.0 17.4 BROS_J0406.6-0407 61.650645 -4.120446 9999.0 17.7 17.5 16.9 BROS_J0407.2-0415 61.814093 -4.256252 9999.0 17.7 17.5 16.9 GLADEbr000 60.873493 -3.998699 776.58 16.4 16.3 16.0 GLADEbr001 60.511959 -3.850282 669.76 19.4 19.3 18.2 GLADEbr002 60.70639 -4.420331 584.97 16.8 16.5 16.1 GLADEbr003 61.009609 -4.161763 550.55 17.1 16.8 18.4 GLADEbr004 61.340942 -4.024267 601.03 19.1 19.6 18.4 GLADEbr005 60.875721 -3.990366 595.34 16.4 16.3 16.0 GLADEbr006 61.244709 -4.505184 821.77 18.6 18.4 17.3 GLADEbr007 60.773819 -3.919802 661.31 16.4 16.3 16.0 GLADEbr008 61.19709 -3.799073 312.54 18.9 19.0 17.6 GLADEbr010 61.260109 -4.550925 812.37 18.5 18.4 17.3 GLADEbr011 61.011189 -4.462371 573.14 18.6 19.4 17.3 GLADEbr012 60.630688 -3.72944 707.06 16.4 16.3 15.9 GLADEbr013 61.256248 -4.29898 831.97 18.6 18.4 17.5 GLADEbr014 60.787174 -3.999526 657.58 16.4 16.3 16.0 GLADEbr015 61.094845 -4.067611 281.12 19.6 19.6 18.4 GLADEbr016 61.197075 -4.243517 427.98 18.7 18.4 17.3 GLADEbr017 60.562199 -3.827767 634.20 19.5 19.3 18.2 GLADEbr018 60.70779 -4.344498 718.37 16.9 16.5 16.1 GLADEbr019 60.7243 -4.66647 903.64 17.3 16.9 16.7 GLADEbr020 60.4174 -4.45656 2691.5 19.3 19.2 18.2 GLADEbr021 60.453968 -4.632778 614.11 19.4 19.2 18.2 GLADEbr022 60.835892 -4.156475 703.00 16.8 16.5 16.1 GLADEbr023 60.6422 -4.6555 748.17 17.3 16.9 16.7 GLADEbr024 60.740658 -4.453944 511.17 16.9 16.5 16.1 GLADEbr026 60.890892 -3.658759 364.06 16.4 19.7 16.0 GLADEbr027 61.041843 -4.541214 755.09 18.6 18.4 18.2 GLADEbr028 60.805511 -4.38675 331.92 16.8 16.5 16.1 GLADEbr030 60.261082 -3.836556 331.80 19.4 19.3 18.2 GLADEbr032 60.796963 -3.628416 365.60 19.8 16.3 16.0 GLADEbr033 61.323677 -4.013155 285.61 19.7 19.6 18.4 GLADEbr034 61.237743 -4.293518 516.20 18.6 18.4 17.4 GLADEbr035 60.230717 -3.930162 527.75 19.4 19.2 18.2 GLADEbr037 61.089005 -4.015666 269.71 19.6 19.6 18.4 GLADEbr038 60.5329 -4.50875 790.67 19.3 19.2 18.1 GLADEbr039 60.992 -4.51195 2679.1 18.6 18.4 18.3 GLADEbr040 60.840626 -4.172586 370.78 16.9 16.5 18.5 GLADEbr041 60.8438 -4.78764 748.17 17.3 16.9 16.6 GLADEbr042 61.153305 -4.615459 338.90 18.5 18.4 17.3 GLADEbr043 60.680756 -4.461996 73.216 19.8 16.5 16.1 GLADEbr044 60.4346 -4.6138 597.03 19.3 19.2 18.1 GLADEbr045 61.099 -4.54441 755.09 18.6 18.4 99.9 GLADEbr046 60.497204 -3.808059 257.57 19.4 19.3 18.1 GLADEbr047 60.3525 -4.45958 1306.1 19.4 19.2 18.2 GLADEbr048 60.3873 -4.56173 602.56 19.4 19.2 18.1 GLADEbr049 60.409405 -4.472772 165.84 19.4 19.2 18.2 GLADEbr050 60.7708 -4.77726 748.17 17.3 16.9 16.6 GLADEbr051 61.219074 -4.492129 151.07 99.9 18.4 17.3 GLADEbr052 61.089291 -3.940388 191.57 19.6 19.6 18.4 GLADEbr053 60.5727 -4.58057 295.12 17.3 19.2 16.7 GLADEbr054 61.108768 -4.082613 118.41 19.7 19.6 18.2 GLADEbr055 61.044437 -4.089826 214.99 19.6 19.6 18.4 GLADEbr056 60.7507 -4.72274 847.22 17.3 19.2 16.7 GLADEbr057 61.1088 -4.08258 123.37 19.7 19.6 18.4 galid with "BROS_*" are based on the BROS catalog, which don't have distant measurements (put 9999.0). The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ; https://github.com/MNiwano/Eclaire).