Search Results - "Imazawa, Ryo"

The Study of X-Ray Flux Variability of M87 by Imazawa, Ryo, Fukazawa, Yasushi, Takahashi, Hiromitsu

“…Abstract We searched for a short-term X-ray variability of the M87 core and jet from archival X-ray data with long exposure data taken by the Suzaku, Chandra,…”
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Far-ultraviolet to Near-infrared Observations of SN 2023ixf: A High-energy Explosion Engulfed in Complex Circumstellar Material by Teja, Rishabh Singh, Singh, Avinash, Basu, Judhajeet, Anupama, G. C., Sahu, D. K., Dutta, Anirban, Swain, Vishwajeet, Nakaoka, Tatsuya, Pathak, Utkarsh, Bhalerao, Varun, Barway, Sudhanshu, Kumar, Harsh, A. J., Nayana, Imazawa, Ryo, Kumar, Brajesh, Kawabata, Koji S.

“…Abstract We present early-phase panchromatic photometric and spectroscopic coverage spanning the far-ultraviolet to near-infrared regime of the nearest…”
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Photometry and Polarimetry of 2010 XC15: Observational Confirmation of E-type Near-Earth Asteroid Pair by Beniyama, Jin, Sako, Shigeyuki, Ohtsuka, Katsuhito, Sekiguchi, Tomohiko, Ishiguro, Masateru, Kuroda, Daisuke, Urakawa, Seirato, Yoshida, Fumi, Takumi, Asami, Maeda, Natsuho, Takahashi, Jun, Takagi, Seiko, Saito, Hiroaki, Nakaoka, Tatsuya, Saito, Tomoki, Ohshima, Tomohito, Imazawa, Ryo, Kagitani, Masato, Takita, Satoshi

“…Asteroid systems such as binaries and pairs are indicative of the physical properties and dynamical histories of small solar system bodies. Although numerous…”
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SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium (II). The Properties of the CSM from Polarimetry and Light-curve Modeling by Uno, Kohki, Nagao, Takashi, Maeda, Keiichi, Kuncarayakti, Hanindyo, Tanaka, Masaomi, Kawabata, Koji S., Nakaoka, Tatsuya, Kawabata, Miho, Yamanaka, Masayuki, Aoki, Kentaro, Isogai, Keisuke, Ogawa, Mao, Tajitsu, Akito, Imazawa, Ryo

“…Abstract Type IIn/Ia-CSM supernovae (SNe IIn/Ia-CSM) are classified by their characteristic spectra, which exhibit narrow hydrogen emission lines originating…”
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(3200) Phaethon polarimetry in the negative branch: new evidence for the anhydrous nature of the DESTINY+ target asteroid by Geem, Jooyeon, Ishiguro, Masateru, Takahashi, Jun, Akitaya, Hiroshi, Kawabata, Koji S, Nakaoka, Tatsuya, Imazawa, Ryo, Mori, Fumiki, Jin, Sunho, Bach, Yoonsoo P, Jo, Hangbin, Kuroda, Daisuke, Hasegawa, Sunao, Yoshida, Fumi, Ishibashi, Ko, Sekiguchi, Tomohiko, Beniyama, Jin, Arai, Tomoko, Ikeda, Yuji, Shinnaka, Yoshiharu, Granvik, Mikael, Siltala, Lauri, Djupvik, Anlaug A, Kasikov, Anni, Pinter, Viktoria, Knudstrup, Emil

“…ABSTRACT We report on the first polarimetric study of (3200) Phaethon, the target of JAXA’s DESTINY+ mission, in the negative branch to ensure its anhydrous…”
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Bridging between Type IIb and Ib Supernovae: SN IIb 2022crv with a Very Thin Hydrogen Envelope by Gangopadhyay, Anjasha, Maeda, Keiichi, Singh, Avinash, A. J., Nayana, Nakaoka, Tatsuya, Kawabata, Koji S., Taguchi, Kenta, Singh, Mridweeka, Chandra, Poonam, Ryder, Stuart D., Dastidar, Raya, Yamanaka, Masayuki, Kawabata, Miho, Alsaberi, Rami Z. E., Dukiya, Naveen, Teja, Rishabh Singh, Ailawadhi, Bhavya, Dutta, Anirban, Sahu, D. K., Moriya, Takashi J., Misra, Kuntal, Tanaka, Masaomi, Chevalier, Roger, Tominaga, Nozomu, Uno, Kohki, Imazawa, Ryo, Hamada, Taisei, Hori, Tomoya, Isogai, Keisuke

“…Abstract We present optical, near-infrared, and radio observations of supernova (SN) SN IIb 2022crv. We show that it retained a very thin H envelope and…”
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SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium. I. The Nature of Type IIn/Ia-CSM SNe from Photometry and Spectroscopy by Uno, Kohki, Maeda, Keiichi, Nagao, Takashi, Nakaoka, Tatsuya, Motohara, Kentaro, Tajitsu, Akito, Konishi, Masahiro, Koyama, Shuhei, Takahashi, Hidenori, Tanaka, Masaomi, Kuncarayakti, Hanindyo, Kawabata, Miho, Yamanaka, Masayuki, Aoki, Kentaro, Isogai, Keisuke, Taguchi, Kenta, Ogawa, Mao, Kawabata, Koji S., Yoshii, Yuzuru, Miyata, Takashi, Imazawa, Ryo

“…Abstract We have performed intensive follow-up observations of a Type IIn/Ia-CSM supernova (SN IIn/Ia-CSM), 2020uem, with photometry, spectroscopy, and…”
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Unravelling the Asphericities in the Explosion and Multifaceted Circumstellar Matter of SN 2023ixf by Singh, Avinash, Teja, Rishabh Singh, Moriya, Takashi J., Maeda, Keiichi, Kawabata, Koji S, Tanaka, Masaomi, Imazawa, Ryo, Nakaoka, Tatsuya, Gangopadhyay, Anjasha, Yamanaka, Masayuki, Swain, Vishwajeet, Sahu, D. K., Anupama, G. C., Kumar, Brajesh, Anche, Ramya M., Sano, Yasuo, Raj, A., Agnihotri, V. K., Bhalerao, Varun, Bisht, D., Bisht, M. S., Belwal, K., Chakrabarti, S. K., Fujii, Mitsugu, Nagayama, Takahiro, Matsumoto, Katsura, Hamada, Taisei, Kawabata, Miho, Kumar, Amit, Kumar, Ravi, Malkan, Brian K., Smith, Paul, Sakagami, Yuta, Taguchi, Kenta, Tominaga, Nozomu, Watanabe, Arata

“…Abstract We present a detailed investigation of photometric, spectroscopic, and polarimetric observations of the Type II SN 2023ixf. Earlier studies have…”
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Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary System by Valtonen, Mauri J., Zola, Staszek, Gupta, Alok C., Kishore, Shubham, Gopakumar, Achamveedu, Jorstad, Svetlana G., Wiita, Paul J., Gu, Minfeng, Nilsson, Kari, Marscher, Alan P., Zhang, Zhongli, Hudec, Rene, Matsumoto, Katsura, Drozdz, Marek, Ogloza, Waldemar, Berdyugin, Andrei V., Reichart, Daniel E., Mugrauer, Markus, Dey, Lankeswar, Pursimo, Tapio, Lehto, Harry J., Ciprini, Stefano, Nakaoka, T., Uemura, M., Imazawa, Ryo, Zejmo, Michal, Kouprianov, Vladimir V., Davidson, James W., Sadun, Alberto, Štrobl, Jan, Weaver, Z. R., Jelínek, Martin

“…We report the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ 287. In the binary black hole model, it is associated…”
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Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability by Gupta, Alok C., Kushwaha, Pankaj, Valtonen, Mauri J., Savchenko, Sergey S., Jorstad, Svetlana G., Imazawa, Ryo, Wiita, Paul J., Gu, Minfeng, Marscher, Alan P., Zhang, Zhongli, Bachev, Rumen, Borman, G. A., Gaur, Haritma, Grishina, T. S., Hagen-Thorn, V. A., Kopatskaya, E. N., Larionov, V. M., Larionova, E. G., Larionova, L. V., Morozova, D. A., Nakaoka, T., Strigachev, A., Troitskaya, Yulia V., Troitsky, I. S., Uemura, M., Vasilyev, A. A., Weaver, Z. R., Zhovtan, A. V.

“…Abstract We study the optical flux and polarization variability of the binary black hole blazar OJ 287 using quasi-simultaneous observations from 2015 to 2023…”
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Observational Implications of OJ 287’s Predicted 2022 Disk Impact in the Black Hole Binary Model by Valtonen, Mauri J., Dey, Lankeswar, Gopakumar, Achamveedu, Zola, Staszek, Lähteenmäki, Anne, Tornikoski, Merja, Gupta, Alok C., Pursimo, Tapio, Knudstrup, Emil, Gomez, Jose L., Hudec, Rene, Jelínek, Martin, Štrobl, Jan, Berdyugin, Andrei V., Ciprini, Stefano, Reichart, Daniel E., Kouprianov, Vladimir V., Matsumoto, Katsura, Drozdz, Marek, Mugrauer, Markus, Sadun, Alberto, Zejmo, Michal, Sillanpää, Aimo, Lehto, Harry J., Nilsson, Kari, Imazawa, Ryo, Uemura, Makoto

“…We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is…”
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Optical and near-infrared photometric and polarimetric monitoring at flaring state of BL Lacertae in 2020–2021 by Hazama, Natsuko, Sasada, Mahito, Imazawa, Ryo, Fukazawa, Yasushi, Kawabata, Koji S, Nakaoka, Tatsuya, Akitaya, Hiroshi

“…Abstract BL Lacertae (BL Lac) was in an unprecedented bright state since 2020 August. We have conducted long-term photometric and polarimetric observations of…”
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The microvariability and wavelength dependence of polarization degree/angle of BL Lacertae in the outburst 2020 to 2021 by Imazawa, Ryo, Sasada, Mahito, Hazama, Natsuko, Fukazawa, Yasushi, Kawabata, Koji S, Nakaoka, Tatsuya, Akitaya, Hiroshi, Bohn, Thomas, Gangopadhyay, Anjasha

“…Abstract We have obtained simultaneous and continuous photo-polarization observations of the blazar BL Lacertae in optical and near-infrared (NIR) bands during…”
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Photometry and Polarimetry of 2010 XC 15 : Observational Confirmation of E-type Near-Earth Asteroid Pair by Beniyama, Jin, Sako, Shigeyuki, Ohtsuka, Katsuhito, Sekiguchi, Tomohiko, Ishiguro, Masateru, Kuroda, Daisuke, Urakawa, Seirato, Yoshida, Fumi, Takumi, Asami, Maeda, Natsuho, Takahashi, Jun, Takagi, Seiko, Saito, Hiroaki, Nakaoka, Tatsuya, Saito, Tomoki, Ohshima, Tomohito, Imazawa, Ryo, Kagitani, Masato, Takita, Satoshi

“…Abstract Asteroid systems such as binaries and pairs are indicative of the physical properties and dynamical histories of small solar system bodies. Although…”
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Refining the OJ 287 2022 impact flare arrival epoch by Valtonen, Mauri J, Zola, Staszek, Gopakumar, A, Lähteenmäki, Anne, Tornikoski, Merja, Dey, Lankeswar, Gupta, Alok C, Pursimo, Tapio, Knudstrup, Emil, Gomez, Jose L, Hudec, Rene, Jelínek, Martin, Štrobl, Jan, Berdyugin, Andrei V, Ciprini, Stefano, Reichart, Daniel E, Kouprianov, Vladimir V, Matsumoto, Katsura, Drozdz, Marek, Mugrauer, Markus, Sadun, Alberto, Zejmo, Michal, Sillanpää, Aimo, Lehto, Harry J, Nilsson, Kari, Imazawa, Ryo, Uemura, Makoto

“…ABSTRACT The bright blazar OJ 287 routinely parades high brightness bremsstrahlung flares, which are explained as being a result of a secondary supermassive…”
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Spectral type and geometric albedo of (98943) 2001 CC21, the Hayabusa2# mission target by Geem, Jooyeon, Ishiguro, Masateru, Granvik, Mikael, Naito, Hiroyuki, Akitaya, Hiroshi, Sekiguchi, Tomohiko, Hasegawa, Sunao, Kuroda, Daisuke, Oono, Tatsuharu, Bach, Yoonsoo P, Jin, Sunho, Imazawa, Ryo, Kawabata, Koji S, Takagi, Seiko, Yoshikawa, Makoto, Djupvik, Anlaug A, Gadeberg, Julie Thiim, Pursimo, Tapio, Pedros, Oliver Durfeldt, Thomsen, Jeppe Sinkbaek, Gray, Zuri

“…ABSTRACT We conducted optical polarimetry and near-infrared spectroscopy of Japan Aerospace Exploration Agency (JAXA)’s Hayabusa2# mission target, (98943) 2001…”
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Intermediate-luminosity Type IIP SN 2021gmj: a low-energy explosion with signatures of circumstellar material by Murai, Yuta, Tanaka, Masaomi, Kawabata, Miho, Taguchi, Kenta, Teja, Rishabh Singh, Nakaoka, Tatsuya, Maeda, Keiichi, Kawabata, Koji S, Nagao, Takashi, Moriya, Takashi J, Sahu, D K, Anupama, G C, Tominaga, Nozomu, Morokuma, Tomoki, Imazawa, Ryo, Inutsuka, Satoko, Isogai, Keisuke, Kasuga, Toshihiro, Kobayashi, Naoto, Kondo, Sohei, Maehara, Hiroyuki, Mori, Yuki, Niino, Yuu, Ogawa, Mao, Ohsawa, Ryou, Okumura, Shin-ichiro, Saito, Sei, Sako, Shigeyuki, Takahashi, Hidenori, Uno, Kohki, Yamanaka, Masayuki

“…ABSTRACT We present photometric, spectroscopic, and polarimetric observations of the intermediate-luminosity Type IIP supernova (SN) 2021gmj from 1 to 386 d…”
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On the need of an ultramassive black hole in OJ 287 by Valtonen, Mauri J, Zola, Staszek, Gopakumar, A, Lähteenmäki, Anne, Tornikoski, Merja, Dey, Lankeswar, Gupta, Alok C, Pursimo, Tapio, Knudstrup, Emil, Gomez, Jose L, Hudec, Rene, Jelínek, Martin, Štrobl, Jan, Berdyugin, Andrei V, Ciprini, Stefano, Reichart, Daniel E, Kouprianov, Vladimir V, Matsumoto, Katsura, Drozdz, Marek, Mugrauer, Markus, Sadun, Alberto, Zejmo, Michal, Sillanpää, Aimo, Lehto, Harry J, Nilsson, Kari, Imazawa, Ryo, Uemura, Makoto, Davidson, James W

“…ABSTRACT The highly variable blazar OJ 287 is commonly discussed as an example of a binary black hole system. The 130 yr long optical light curve is well…”
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Diffraction modelling of a 2023 March 5 stellar occultation by subkilometer-sized asteroid (98943) 2001 CC21 by Arimatsu, Ko, Yoshida, Fumi, Hayamizu, Tsutomu, Ida, Miyoshi, Hashimoto, George L, Abe, Takashi, Akitaya, Hiroshi, Aratani, Akari, Fukuda, Hidekazu, Fujita, Yasuhide, Fujiwara, Takao, Horikawa, Toshihiro, Iihoshi, Tamio, Imamura, Kazuyoshi, Imazawa, Ryo, Kasebe, Hisashi, Kawasaki, Ryosuke, Kishimoto, Hiroshi, Mishima, Kazuhisa, Miyachi, Machiko, Mizutani, Masanori, Nakajima, Maya, Nakatani, Hiroyoshi, Okamura, Kazuhiko, Okanobu, Misaki, Okuda, Masataka, Suzuki, Yuji, Tatsumi, Naoto, Uno, Masafumi, Yamamura, Hidehito, Yasue, Mikoto, Yoshihara, Hideki, Hirabayashi, Masatoshi, Yoshikawa, Makoto

“…Abstract We present an analysis of a stellar occultation event caused by a near-Earth asteroid (98943) 2001 CC21, an upcoming flyby target in the Hayabusa2…”
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Multicolor and multi-spot observations of Starlink’s Visorsat by Horiuchi, Takashi, Hanayama, Hidekazu, Ohishi, Masatoshi, Nakaoka, Tatsuya, Imazawa, Ryo, Kawabata, Koji S, Takahashi, Jun, Onozato, Hiroki, Saito, Tomoki, Yamanaka, Masayuki, Nogami, Daisaku, Tampo, Yusuke, Kojiguchi, Naoto, Ito, Jumpei, Shibata, Masaaki, Schramm, Malte, Oasa, Yumiko, Kanai, Takahiro, Oide, Kohei, Murata, Katsuhiro L, Hosokawa, Ryohei, Takamatsu, Yutaka, Imai, Yuri, Ito, Naohiro, Niwano, Masafumi, Takagi, Seiko, Ono, Tatsuharu, Kouprianov, Vladimir V

“…Abstract This study provides the results of simultaneous multicolor observations for the first Visorsat (STARLINK-1436) and the ordinary Starlink satellite…”
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