Explanipedia

XRISM reveals a variable, multi-phase outflow-inflow structure during the X-ray obscured 2024 outburst of the black hole transient V4641 Sgr Open

Maxime Parra, M. Shidatsu, Ryota Tomaru, Chris Done, T. Muñoz‐Darias , et al. · 2025

We report the results of a simultaneous X-ray and optical spectroscopy campaign on the Galactic black hole X-ray binary V4641 Sgr, carried out with XRISM and the Seimei telescope during a low-luminosity phase towards the end of its 2024 ou…

Investigating MAXI J1752$-$457 with NuSTAR in the aftermath of a superburst Open

Sean N. Pike, H. Negoro, D. J. K. Buisson, Benjamin M. Coughenour, J. Gerber , et al. · 2025

We present two NuSTAR observations of the X-ray transient, MAXI J1752$-$457, following a superburst which was observed by MAXI/GSC in November, 2024. NuSTAR follow-up confirmed that MAXI J1752$-$457 is coincident with the previously observ…

Searching for similarities in the accretion flow of Seyfert 1 galaxies and cataclysmic variables based on the flare profiles of IRAS 13224–3809, 1H 0707–495, Mrk 766, and MV Lyr Open

A. Dobrotka, H. Negoro, P., Bez'ak · 2024

Aims. We studied the fast variability of three selected active galactic nuclei (AGNs), IRAS 13224−3809, 1H 0707−495, and Mrk 766, and the cataclysmic variable MV Lyr, which were observed by the XMM-Newton and Kepler spacecrafts, respective…

Evolution of X-ray and optical rapid variability during the low/hard state in the 2018 outburst of MAXI J1820+070 = ASASSN-18ey Open

M. Kimura, H. Negoro, S. Yamada, W. Iwakiri, Shigeyuki Sako , et al. · 2024

We performed shot analyses of X-ray and optical subsecond flares observed during the low/hard state of the 2018 outburst in MAXI J1820+070. Optical shots were less spread than X-ray shots. The amplitude of X-ray shots was highest at the on…

Searching for similarities in the accretion flow of Seyfert 1 galaxies and cataclysmic variables based on flare profiles of IRAS 13224-3809, 1H 0707-495, Mrk 766 and MV Lyr Open

A. Dobrotka, H. Negoro, Pavol Bezák · 2024

AIMS: We studied fast variability of three selected AGNs, IRAS 13224-3809, 1H 0707-495 and Mrk 766, and the cataclysmic variable MV Lyr observed by XMM-Newton and Kepler spacecrafts, respectively. Our goal is to search for common origin of…

Evolution of accretion disk structure of the black hole X-ray binary MAXI J1820+070 during the rebrightening phase Open

T. Yoshitake, M. Shidatsu, Yoshihiro Ueda, Daisaku Nogami, Katsuhiro L. Murata , et al. · 2024

To understand the evolution of global accretion disk structure in the “rebrightening” phase of MAXI J1820+070, we perform a comprehensive analysis of its near infrared/optical/UV to X-ray spectral energy distribution (SED) utilizing data o…

The 2018 X-Ray and Radio Outburst of Magnetar XTE J1810-197 Open

E. V. Gotthelf, J. P. Halpern, Jason Alford, T. Mihara, H. Negoro , et al. · 2024

We present the earliest X-ray observations of the 2018 outburst of XTE. J1810-197, the first outburst since its 2003 discovery as the prototypical transient and radio-emitting anomalous X-ray pulsar (AXP). The Monitor of Allsky X-ray Image…

EXTRAORDINARY LUMINOUS SOFT X-RAY TRANSIENT MAXI J0158–744 AS AN IGNITION OF A NOVA ON A VERY MASSIVE O-Ne WHITE DWARF Open

M. Morii, H. Tomida, Minoru Kimura, F. Suwa, H. Negoro , et al. · 2024

We present the observation of an extraordinary luminous soft X-ray transient, MAXI J0158-744, by the Monitor of All-sky X-ray Image (MAXI) on 2011 November 11. This transient is characterized by a soft X-ray spectrum, a short duration (1.3…

Accretion Spin-up and a Strong Magnetic Field in the Slow-spinning Be X-Ray Binary MAXI J0655-013 Open

Sean N. Pike, M. Sugizaki, J. van den Eijnden, Benjamin M. Coughenour, Amruta Jaodand , et al. · 2023

We present Monitor of All-sky X-ray Image (MAXI) and Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the Be X-ray binary, MAXI J0655−013, in outburst. NuSTAR observed the source once early in the outburst, when spectral anal…

Accretion spin-up and a strong magnetic field in the slow-spinning Be X-ray binary MAXI J0655-013 Open

Sean N. Pike, M. Sugizaki, J. van den Eijnden, Benjamin M. Coughenour, Amruta Jaodand , et al. · 2023

We present MAXI and NuSTAR observations of the Be X-ray binary, MAXI J0655-013, in outburst. NuSTAR observed the source once early in the outburst, when spectral analysis yields a bolometric (0.1--100 keV), unabsorbed source luminosity of …

GRB 221009A: Discovery of an Exceptionally Rare Nearby and Energetic Gamma-Ray Burst Open

Maia A. Williams, J. A. Kennea, S. Dichiara, Kohei Kobayashi, W. Iwakiri , et al. · 2023

We report the discovery of the unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by the Neil Gehrels Swift Observatory (Swift), Monitor of All-sky X-ray Image, and Neutron Star Interior Composition Explorer Mis…

GRB 221009A: Discovery of an Exceptionally Rare Nearby and Energetic Gamma-Ray Burst Open

Maia A. Williams, J. A. Kennea, S. Dichiara, Kohei Kobayashi, W. Iwakiri , et al. · 2023

We report the discovery of the unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by the Neil Gehrels Swift Observatory (Swift), Monitor of All-sky X-ray Image (MAXI), and Neutron Star Interior Composition Explo…

Discovery of a new supergiant fast X-ray transient MAXI J0709−159 associated with the Be star LY Canis Majoris Open

M. Sugizaki, T. Mihara, Kohei Kobayashi, H. Negoro, M. Shidatsu , et al. · 2022

We report on the discovery of a new supergiant fast X-ray transient (SFXT), MAXI J0709−159, and its identification with LY CMa (also known as HD 54786). On 2022 January 25, a new flaring X-ray object, named MAXI J0709−159, was detected by …

MAXI : Monitor of All-sky X-ray Image Open

T. Mihara, H. Tsunemi, H. Negoro · 2022

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky monitor onboard the International Space Station (ISS).

Multiwavelength observations of the black hole X-ray binary MAXI J1820+070 in the rebrightening phase Open

T. Yoshitake, M. Shidatsu, Yoshihiro Ueda, Shin Mineshige, Katsuhiro L. Murata , et al. · 2022

We report the results of quasi-simultaneous multiwavelength (near-infrared, optical, UV, and X-ray) observations of the Galactic X-ray black hole binary MAXI J1820+070 performed in 2019 May 10–13, ∼60 d after the onset of the first rebrigh…

Discovery and Long-term Broadband X-Ray Monitoring of Galactic Black Hole Candidate MAXI J1803–298 Open

M. Shidatsu, Kohei Kobayashi, H. Negoro, W. Iwakiri, S. Nakahira , et al. · 2022

We report the results from the broadband X-ray monitoring of the new Galactic black hole candidate MAXI J1803−298 with MAXI/GSC and Swift/BAT during its outburst. After the discovery on 2021 May 1, the soft X-ray flux below 10 keV rapidly …

MAXI and NuSTAR Observations of the Faint X-Ray Transient MAXI J1848-015 in the GLIMPSE-C01 Cluster Open

Sean N. Pike, H. Negoro, John A. Tomsick, Matteo Bachetti, McKinley C. Brumback , et al. · 2022

We present the results of Monitor of All-sky X-ray Image (MAXI) monitoring and two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the recently discovered faint X-ray transient MAXI J1848015. Analysis of the MAXI light curve…

A Comprehensive X-Ray Report on AT2019wey Open

Yuhan Yao, S. R. Kulkarni, Keith C. Gendreau, Gaurava K. Jaisawal, Teruaki Enoto , et al. · 2021

Here, we present MAXI, Swift, NICER, NuSTAR, and Chandra observations of the X-ray transient AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234). From spectral and timing analyses we classify it as a Galactic low-mass X-ray binary (LM…

The correlation of X-ray binaries between X-ray and Optical light with MAXI and TESS Open

Ryohei Hosokawa, Kawai Nobuyuki, H. Negoro, T. Mihara, Uemura Makoto , et al. · 2021

We searched for the correlation between X-ray and optical variabilities of X-ray binaries by comparing the light curves observed by MAXI and TESS at the same time. First, from MAXI public light curves of more than 400 X-ray sources, We cho…

Gravitational Wave Physics and Astronomy in the nascent era Open

M. Arimoto, Hideki Asada, M. L. Cherry, Michiko S. Fujii, Y. Fukazawa , et al. · 2021

The detections of gravitational waves (GW) by LIGO/Virgo collaborations provide various possibilities to physics and astronomy. We are quite sure that GW observations will develop a lot both in precision and in number owing to the continuo…

Gravitational wave physics and astronomy in the nascent era Open

M. Arimoto, Hideki Asada, M. L. Cherry, Michiko S. Fujii, Y. Fukazawa , et al. · 2021

The detections of gravitational waves (GW) by the LIGO/Virgo collaborations provide various possibilities for both physics and astronomy. We are quite sure that GW observations will develop a lot, both in precision and in number, thanks to…

The RS CVn–type Star GT Mus Shows Most Energetic X-Ray Flares Throughout the 2010sRyo Sasaki Open

R. Sasaki, Y. Tsuboi, W. Iwakiri, S. Nakahira, Yoshitomo Maeda , et al. · 2021

We report that the RS CVn–type star GT Mus (HR 4492, HD 101379+HD 101380) was the most active star in the X-ray sky in the last decade in terms of the scale of recurrent energetic flares. We detected 11 flares from GT Mus in 8 yr of observ…

NICER follow-up of the Be X-ray pulsar Swift J1626.6-5156 Open

W. Iwakiri, M. J. Wolff, K. Pottschmidt, Keith C. Gendreau, H. Negoro , et al. · 2021

NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.

Discovery and Identification of MAXI J1621–501 as a Type I X-Ray Burster with a Super-orbital Period Open

Nicholas Gorgone, C. Kouveliotou, H. Negoro, R. A. M. J. Wijers, E. Bozzo , et al. · 2019

MAXI J1621–501 is the first Swift /XRT Deep Galactic Plane Survey transient that was followed up with a multitude of space missions ( NuSTAR , Swift , Chandra , NICER , INTEGRAL , and MAXI) and ground-based observatories ( Gemini , IRSF, a…

Similar shot profile morphology of fast variability in a cataclysmic variable, X-ray binary, and blazar: The MV Lyrae case Open

A. Dobrotka, H. Negoro, Shin Mineshige · 2019

Context. The cataclysmic variable MV Lyr has been found to be present in the Kepler field, yielding a light curve with the duration of almost 1500 days with 60 s cadence. Such high quality data of this nova-like system with obvious fast op…

X-Ray, Optical, and Near-infrared Monitoring of the New X-Ray Transient MAXI J1820+070 in the Low/Hard State Open

M. Shidatsu, S. Nakahira, Satoshi Yamada, T. Kawamuro, Yoshihiro Ueda , et al. · 2018

We report X-ray, optical, and near-infrared monitoring of the new X-ray transient MAXI J1820+070 discovered with MAXI on 2018 March 11. Its X-ray intensity reached ∼2 crab at 2–20 keV at the end of March, and then gradually decreased until…

Discovery and state transitions of the new Galactic black hole candidate MAXI J1535−571 Open

S. Nakahira, M. Shidatsu, Kazuo Makishima, Yoshihiro Ueda, K. Yamaoka , et al. · 2018

We report on the detection and subsequent X-ray monitoring of the new Galactic black hole candidate MAXI J1535−571 with the Gas Slit Camera onboard Monitor of All-sky X-ray Image (MAXI/GSC). After the discovery on 2017 September 2, made in…

MAXI upper limits of the electromagnetic counterpart of GW170817 Open

Satoshi Sugita, N. Kawai, S. Nakahira, H. Negoro, Motoko Serino , et al. · 2018

We report on the Monitor of All-sky X-ray Image (MAXI) observation of the gravitational-wave (GW) event GW170817 and the electromagnetic counterpart of GW170817. GW170817 is a binary neutron star coalescence candidate detected by the Advan…

X線トランジェント天体MAXI J1807+132とMAXI J1535-571 の発見と追観測 Open

めぐみ志達, 聡志中平, 優太朗橘, 健敏吉井, 均根来 , et al. · 2018

The 7-year MAXI/GSC Source Catalog of the Low-Galactic-latitude Sky (3MAXI) Open

T. Hori, M. Shidatsu, Yoshihiro Ueda, T. Kawamuro, M. Morii , et al. · 2018

We present the first MAXI/GSC X-ray source catalog in the low-Galactic-latitude sky outside the Galactic center region ( , l < 30°, and l > 330°) based on 7-year data from 2009 August 13 to 2016 July 31. To overcome source confusion in cro…

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