OISTER Optical and Near-Infrared Observations for the field of 3FGL J1804.5-0850 close to the position of IceCube-181023A

ATel #12145; M. Yamanaka (Hiroshima Univ.), R. Itoh (Tokyo Institute of Tech.), K. Ohta (Kyoto Univ.), T. Morokuma (Univ. of Tokyo), K. S. Kawabata (Hiroshima Univ.), K. Isogai, N. Kojiguchi (Kyoto Univ.), K. Morihana (Nagoya Univ.), H. Nagashima, M. Sasada, T. Nakaoka, M. Kawabata, K. Takagi (Hiroshima Univ.), J. Takahashi (Hyogo Univ.), J. de Leon (University of Tokyo), T. Horiuchi (Ishigaki-jima Astronomical Observatory, NAOJ), and R. Ohsawa (Univ. of Tokyo) on the behalf of OISTER.
on 28 Oct 2018; 16:10 UT
Credential Certification: Masayuki Yamanaka (masyamanaka@hiroshima-u.ac.jp)

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We performed follow-up imaging observations of the field around 3FGL J1804.5-0850, (R.A., Dec.)=(271.13d, -8.842d) in J2000, in optical and near-infrared wavelengths in the framework of the Optical and Infrared Synergetic Telescopes for Education and Research (OISTER). This source is the closest Fermi source which is categorized as an unidentified source in the 3FGL catalog (Acero et al. 2015) to the central position of the IceCube localization (1.3 degrees from best fit refined direction). and was encouraged for follow-up observations (Blaufuss et al. 2018, GCN 23375).

The positional uncertainty of the source is about 11 arcmin in diameter (95% CL), and we covered the several to 10 arcmin field of view mostly centered on the source position. We covered about 10x10 arcmin^2 region centered on the source position. Considering the moderately large Galactic extinction (Av~3.1; Schlafly et al. 2011), we prioritized the redder-band filters. We performed quick analyses of the imaging data and do not find any significant transients compared to the PS1 catalog. Summary of the observation details are shown below. Limiting magnitudes of the images are given at S/N=3. Magnitudes are given as the Vega system. Observation epochs are given in UT.

Observatory: Hiroshima Astronomical Observatory
Telescope: 1.5-m Kanata telescope
Instrument: Hiroshima Optical and Near-InfraRed camera (HONIR; Akitaya et al. 2014)
Filter: R and Ks-bands (simultaneously)
Time: 09:09:51-10:25:58 (Oct 24), 09:14:19-11:04:35 (Oct 25)
Position: (18:04:31.6, -08:50:54) (Oct 24), (18:04:32.8, -08:50:51) (Oct 25)
Field of view (FoV): 10’ arcmin square
Total exposure: 5225s in R, 4400s in Ks (Oct 24), 4465s in R, 3760s in Ks (Oct 25)
Limiting magnitudes: R=19.6 and Ks=15.5 mag (Oct 24); R=19.8 and Ks=15.5 mag (Oct 25).

Observatory: Nishi-Harima Astronomical Observatory
Telescope: 2.0-m Nayuta telescope
Instrument: Nishi-harima Infrared Camera (NIC; Ishiguro et al. 2011; Takahashi et al. 2013)
Filter: J, H, and Ks-band (simultaneously)
Time: 09:11:57-10:14:49 (Oct 24), 08:45:42-10:24:05 (Oct 25)
Position: (18:04:33, -08:50:08) (Oct 24), (18:04:33, -08:50:25) (Oct 25)
Field of view (FoV): 2.7 arcmin square
Total exposure: 2400s (Oct 24) 3600s (Oct 25)
Limiting magnitudes: J=18.1, H=17.6 and Ks=16.6 mag (Oct 24), J=19.3, H = 19.0, and Ks = 17.9 (Oct 25).

Observatory: South Africa Astronomical Observatory (SAAO)
Telescope: 1.4-m InfraRed Survey Facility (IRSF)
Instrument: Simultaneous three-color InfraRed Imager for Unbiased Survey (SIRIUS; Nagayama e al. 2003)
Filter J, H, and Ks-band (simultaneously)
Time: 18:06:57-18:43:08 (Oct 24), 18:06:20-18:31:12 (Oct 25)
Position: (18:04:32.4, -08:51:07) (Oct 24), (18:04:34.5, -08:51:08) (Oct 25)
The field of view (FoV): 7.7 arcmin square
Total exposure: 1800s (Oct 24), 1200s (Oct 25)
Limiting magnitudes: J=19.4 and H=18.9 mag (Oct 24), and J=19.1, H=18.6, and Ks=18.1 mag (Oct 25)

Observatory: Kyoto University
Telescope: 0.4-m telescope
Instrument: CCD(SBIG STT-3200me?
Filter: Ic
Time: 09:17:19-11:26:42 (Oct 24) and 09:08:37-11:27:23 (Oct 25)
Position: (18:04:26.8, -08:46 :01) (Oct 24) (18:04:25.5, -08:48:05) (Oct 25)
The field of view (FoV): 10 arcmin square
Total exposure: 5760s (Oct 24)?8040s (Oct 25)
Limiting magnitudes: Ic=18.2 mag