1. Follow-up Observations for IceCube-170922A: Detection of Rapid Near-Infrared Variability and Intensive Monitoring of TXS 0506+056
- Author
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Masayuki Yamanaka, Masaki Takayama, Wei Liu, Mahito Sasada, Hiroki Kimura, Ryuhei Ohnishi, Nozomu Tominaga, C. K. Gilligan, Yuina Yamazaki, Tomoki Morokuma, Ryou Ohsawa, Koji S. Kawabata, Shigeyuki Sako, Kumiko Morihana, Takuji Yamashita, Shigehiro Nagataki, Katsuhiro L. Murata, Michitoshi Yoshida, Hiroki Mori, Maiko Chogi, Masaomi Tanaka, Yoshiyuki Inoue, Mariko Kimura, Yasuyuki Wakamatsu, Yousuke Utsumi, Kengo Takagi, Miho Kawabata, Ruochen Huang, Naoki Kawahara, Yasuyuki T. Tanaka, Yoshiki Matsuoka, Hiroki Nagashima, Ryosuke Itoh, Kouji Ohta, Tatsuya Nakaoka, Taisei Abe, Satoshi Honda, and Keisuke Isogai
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,Near-infrared spectroscopy ,Polarimetry ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Wavelength ,Amplitude ,Neutrino detector ,Space and Planetary Science ,0103 physical sciences ,14. Life underwater ,Neutrino ,Blazar ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics - Abstract
We present our follow-up observations to search for an electromagnetic counterpart of the IceCube high-energy neutrino, IceCube-170922A. Monitoring observations of a likely counterpart, TXS 0506+056, are also described. First, we quickly took optical and near-infrared images of 7 flat-spectrum radio sources within the IceCube error region right after the neutrino detection and found a rapid flux decline of TXS 0506+056 in Kanata/HONIR J-band data. Motivated by this discovery, intensive follow-up observations of TXS 0506+056 are continuously done, including our monitoring imaging observations, spectroscopic observations, and polarimetric observations in optical and near-infrared wavelengths. TXS 0506+056 shows a large amplitude (~1.0 mag) variability in a time scale of several days or longer, although no significant variability is detected in a time scale of a day or shorter. TXS 0506+056 also shows a bluer-when-brighter trend in optical and near-infrared wavelengths. Structure functions of variabilities are examined and indicate that TXS 0506+056 is not a special blazar in terms of optical variability. Polarization measurement results of TXS 0506+056 are also discussed., 19 pages, 10 figures, 4 tables. Accepted for publication in Publications of the Astronomical Society of Japan (PASJ)
- Published
- 2020