Search Results - "Kawabata, Koji S."

A type Ia supernova at the heart of superluminous transient SN 2006gy by Jerkstrand, Anders, Maeda, Keiichi, Kawabata, Koji S

“…Superluminous supernovae radiate up to 100 times more energy than normal supernovae. The origin of this energy and the nature of the stellar progenitors of…”
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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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Three-dimensional Explosion Geometry of Stripped-envelope Core-collapse Supernovae. II. Modeling of Polarization by Tanaka, Masaomi, Maeda, Keiichi, Mazzali, Paolo A., Kawabata, Koji S., Nomoto, Ken'ichi

“…We present modeling of line polarization to study the multidimensional geometry of stripped-envelope core-collapse supernovae (SNe). We demonstrate that a…”
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Narrow Fe–Kα Reverberation Mapping Unveils the Deactivated Broad-line Region in a Changing-look Active Galactic Nucleus by Noda, Hirofumi, Mineta, Taisei, Minezaki, Takeo, Sameshima, Hiroaki, Kokubo, Mitsuru, Kawamuro, Taiki, Yamada, Satoshi, Horiuchi, Takashi, Matsumoto, Hironori, Watanabe, Makoto, Morihana, Kumiko, Itoh, Yoichi, Kawabata, Koji S., Fukazawa, Yasushi

“…Abstract “Changing-look active galactic nuclei” (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic…”
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Late-phase Spectropolarimetric Observations of Superluminous Supernova SN 2017egm to Probe the Geometry of the Inner Ejecta by Saito, Sei, Tanaka, Masaomi, Moriya, Takashi J., Bulla, Mattia, Leloudas, Giorgos, Inserra, Cosimo, Lee, Chien-Hsiu, Kawabata, Koji S., Mazzali, Paolo

“…We present our spectropolarimetric observations of SN 2017egm, a Type I superluminous supernova (SLSN-I) in a nearby galaxy NGC 3191, with the Subaru telescope…”
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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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SN 2018gj: A Short Plateau Type II Supernova with Persistent Blueshifted Ha Emission by Teja, Rishabh Singh, Singh, Avinash, Sahu, D. K., Anupama, G. C., Kumar, Brajesh, Nakaoka, Tatsuya, Kawabata, Koji S, Yamanaka, Masayuki, Takey, Ali, Kawabata, Miho

“…Abstract We present an extensive, panchromatic photometric (UV, optical, and near-IR) and low-resolution optical spectroscopic coverage of a Type IIP supernova…”
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Interstellar Polarization Survey. III. Relation between Optical Polarization and Reddening in the General Interstellar Medium by Angarita, Y., Versteeg, M. J. F., Haverkorn, M., Rodrigues, C. V., Magalhães, A. M., Santos-Lima, R., Kawabata, Koji S.

“…Abstract Optical starlight can be partially polarized while propagating through the dusty, magnetized interstellar medium (ISM). The polarization efficiency…”
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Magnetic Fields in the Southern Coalsack and Beyond by Versteeg, M. J. F., Angarita, Y., Magalhães, A. M., Haverkorn, M., Rodrigues, C. V., Santos-Lima, R., Kawabata, Koji S.

“…Abstract Starlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic…”
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Light-curve properties of SN 2017fgc and HV SNe Ia by Burgaz, Umut, Maeda, Keiichi, Kalomeni, Belinda, Kawabata, Miho, Yamanaka, Masayuki, Kawabata, Koji S, Kawahara, Naoki, Nakaoka, Tatsuya

“…ABSTRACT Photometric and spectroscopic observations of Type Ia supernova (SN) 2017fgc, which cover the period from −12 to + 137 d since the B-band maximum are…”
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Spectropolarimetry of the superwind filaments of the starburst galaxy M 82 II: Kinematics of the dust surrounding the nuclear starburst by Yoshida, Michitoshi, Kawabata, Koji S, Ohyama, Youichi, Itoh, Ryosuke, Hattori, Takashi

“…Abstract We performed deep spectropolarimetric observations of the prototypical starburst galaxy M 82 with the Subaru Telescope in order to study the…”
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Tomographic Imaging of the Sagittarius Spiral Arm's Magnetic Field Structure by Doi, Yasuo, Nakamura, Kengo, Kawabata, Koji S., Matsumura, Masafumi, Akitaya, Hiroshi, Coudé, Simon, Rodrigues, Claudia V., Kwon, Jungmi, Tamura, Motohide, Tahani, Mehrnoosh, Magalhães, Antonio Mario, Santos-Lima, Reinaldo, Angarita, Yenifer, Versteeg, José, Haverkorn, Marijke, Hasegawa, Tetsuo, Sadavoy, Sarah, Arzoumanian, Doris, Bastien, Pierre

“…Abstract The Galactic global magnetic field is thought to play a vital role in shaping Galactic structures such as spiral arms and giant molecular clouds…”
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Interstellar Polarization Survey. II. General Interstellar Medium by Versteeg, M. J. F., Magalhães, A. M., Haverkorn, M., Angarita, Y., Rodrigues, C. V., Santos-Lima, R., Kawabata, Koji S.

“…Abstract Magnetic fields permeate the entire Galaxy and are essential to, for example, the regulation of several stages of the star formation process and…”
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Calcium-rich Transient SN 2019ehk in a Star-forming Environment: Yet Another Candidate for a Precursor of a Double Neutron-star Binary by Nakaoka, Tatsuya, Maeda, Keiichi, Yamanaka, Masayuki, Tanaka, Masaomi, Kawabata, Miho, Moriya, Takashi J., Kawabata, Koji S., Tominaga, Nozomu, Takagi, Kengo, Imazato, Fumiya, Morokuma, Tomoki, Sako, Shigeyuki, Ohsawa, Ryou, Nagao, Takashi, Jiang, Ji-an, Burgaz, Umut, Taguchi, Kenta, Uemura, Makoto, Akitaya, Hiroshi, Sasada, Mahito, Isogai, Keisuke, Otsuka, Masaaki, Maehara, Hiroyuki

“…Abstract We present optical and near-infrared observations of SN 2019ehk, which was initially reported as a Type Ib supernova (SN). We show that it evolved to…”
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Interstellar Polarization Survey. IV. Characterizing the Magnetic Field Strength and Turbulent Dispersion Using Optical Starlight Polarization in the Diffuse Interstellar Medium by Angarita, Y., Versteeg, M. J. F., Haverkorn, M., Marchal, A., Rodrigues, C. V., Magalhães, A. M., Santos-Lima, R., Kawabata, Koji S.

“…Abstract Angular dispersion functions are typically used to estimate the fluctuations in polarization angle around the mean magnetic field orientation in dense…”
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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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SN 2017czd: A Rapidly Evolving Supernova from a Weak Explosion of a Type IIb Supernova Progenitor by Nakaoka, Tatsuya, Moriya, Takashi J., Tanaka, Masaomi, Yamanaka, Masayuki, Kawabata, Koji S., Maeda, Keiichi, Kawabata, Miho, Kawahara, Naoki, Itagaki, Koichi, Ouchi, Ryoma, Blinnikov, Sergei I., Tominaga, Nozomu, Uemura, Makoto

“…We present optical and near-infrared observations of the rapidly evolving supernova (SN) 2017czd that shows hydrogen features. The optical light curves exhibit…”
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Origins of the Long-term Variability of the Near-infrared Emission of the Black Hole X-Ray Binary GRS 1915+105 in the X-Ray Low Luminous State by Imazato, Fumiya, Sasada, Mahito, Uemura, Makoto, Fukazawa, Yasushi, Takahashi, Hiromitsu, Nakaoka, Tatsuya, Akitaya, Hiroshi, Kawabata, Koji S., Akimoto, Masanori, Fujisawa, Kenta

“…Abstract Since 2018 July, the black hole X-ray binary GRS 1915+105 has been in an X-ray low luminous state (XLLS), which is the faintest period ever observed…”
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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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