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J-GEM optical and near-infrared follow-up of gravitational wave events during LIGO's and Virgo's third observing run
Mahito Sasada, Yousuke Utsumi, Ryosuke Itoh +68
The Laser Interferometer Gravitational-wave Observatory Scientific Collaboration and Virgo Collaboration (LVC) sent out 56 gravitational-wave (GW) notices during the third observin…
X-ray, Optical, and Near-infrared Monitoring of the New X-ray Transient MAXI J1820+070 in the Low/hard State
Megumi Shidatsu, Satoshi Nakahira, Satoshi Yamada +26
We report X-ray, optical, and near-infrared monitoring of the new X-ray transient MAXI J1820070 discovered with MAXI on 2018 March 11. Its X-ray intensity reached Crab…
ThunderKAT: The MeerKAT Large Survey Project for Image-Plane Radio Transients
R. Fender, P. A. Woudt, R. Armstrong +59
ThunderKAT is the image-plane transients programme for MeerKAT. The goal as outlined in 2010, and still today, is to find, identify and understand high-energy astrophysical process…
Kilonova from post-merger ejecta as an optical and near-infrared counterpart of GW170817
Masaomi Tanaka, Yousuke Utsumi, Paolo A. Mazzali +42
Recent detection of gravitational waves from a neutron star (NS) merger event GW170817 and identification of an electromagnetic counterpart provide a unique opportunity to study th…
J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817
Yousuke Utsumi, Masaomi Tanaka, Nozomu Tominaga +57
The first detected gravitational wave from a neutron star merger was GW170817. In this study, we present J-GEM follow-up observations of SSS17a, an electromagnetic counterpart of G…
Broad-Lined Supernova 2016coi with Helium Envelope
Masayuki Yamanaka, Tatsuya Nakaoka, Masaomi Tanaka +38
We present the early-phase spectra and the light curves of the broad-lined supernova (SN) 2016coi from to days after the estimated explosion date. This SN was initially…
J-GEM Follow-Up Observations of The Gravitational Wave Source GW151226
Michitoshi Yoshida, Yousuke Utsumi, Nozomu Tominaga +35
We report the results of optical--infrared follow-up observations of the gravitational wave (GW) event GW151226 detected by the Advanced LIGO in the framework of J-GEM (Japanese co…
No Evidence of Intrinsic Optical/Near-Infrared Linear Polarization for V404 Cygni During its Bright Outburst in 2015: Broadband Modeling and Constraint on Jet Parameters
Y. T. Tanaka, R. Itoh, M. Uemura +39
We present simultaneous optical and near-infrared (NIR) polarimetric results for the black hole binary V404 Cygni spanning the duration of its 7-day long optically-brightest phase…
Two fast X-ray transients in archival Chandra data
A. Glennie, P. G. Jonker, R. P. Fender +2
We present the discovery of two new X-ray transients in archival Chandra data. The first transient, XRT 110103, occurred in January 2011 and shows a sharp rise of at least three or…
Low-Mass X-Ray Binary MAXI J1421-613 Observed by MAXI GSC and Swift XRT
Motoko Serino, Megumi Shidatsu, Yoshihiro Ueda +6
Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, i…
Multi-wavelength observations of the black widow pulsar 2FGL J2339.6-0532 with OISTER and Suzaku
Yoichi Yatsu, Jun Kataoka, Yosuke Takahashi +41
Multi-wavelength observations of the black-widow binary system 2FGL J2339.6-0532 are reported. The Fermi gamma-ray source 2FGL J2339.6-0532 was recently categorized as a black wido…
Suzaku Observation of the Black Hole Binary 4U 1630--47 in the Very High State
Takafumi Hori, Yoshihiro Ueda, Megumi Shidatsu +7
We report the results from an X-ray and near-infrared observation of the Galactic black hole binary 4U 1630--47 in the very high state, performed with {\it Suzaku} and IRSF around…
Accretion disk and ionized absorber of the 9.7-hour dipping black hole binary MAXI J1305-704
Megumi Shidatsu, Yoshihiro Ueda, Satoshi Nakahira +14
We report the results from X-ray studies of the newly discovered black hole candidate MAXI J1305-704 based on Suzaku and Swift observations in the low/hard and high/soft states, re…
Dense optical and near-infrared monitoring of CTA 102 during high state in 2012 with OISTER: Detection of intra-night "orphan polarized flux flare"
Ryosuke Itoh, Yasushi Fukazawa, Yasuyuki T. Tanaka +35
CTA 102, classified as a flat spectrum radio quasar at z=1.037, produced exceptionally bright optical flare in 2012 September. Following Fermi-LAT detection of enhanced gamma-ray a…
Near-Infrared and X-Ray Observations of XSS J12270-4859
Kei Saitou, Masahiro Tsujimoto, Ken Ebisawa +5
XSS J12270-4859 (J12270) is an enigmatic source of unknown nature. Previous studies revealed that the source has unusual X-ray temporal characteristics, including repetitive short-…
X-Ray and Near-Infrared Observations of GX 339-4 in the Low/Hard State with Suzaku and IRSF
Megumi Shidatsu, Yoshihiro Ueda, Fumie Tazaki +10
X-ray and near-infrared (--) observations of the Galactic black hole binary GX 339--4 in the low/hard state were performed with Suzaku and IRSF in 2009 March. The…