Circumbinary Disk Spectra Irradiated by Two Central Accretion Disks in a Binary Black Hole System

Autor: Yunewoo Lee, Atsuo T. Okazaki, Kimitake Hayasaki

Publikováno v: The Astrophysical Journal, Vol 975, Iss 1, p 141 (2024)

We study the effect of irradiation from two accretion disks (minidisks) around respective black holes of stellar-to-intermediate masses in a circular binary on the spectrum of a circumbinary disk (CBD) surrounding them. We assume the CBD to be a stan

Externí odkaz: https://doaj.org/article/2b16b7e9b8f846e2bf7cd3362545345d

X-Ray Spectral Variations of Circinus X-1 Observed with NICER throughout an Entire Orbital Cycle

Autor: Mayu Tominaga, Masahiro Tsujimoto, Ken Ebisawa, Teruaki Enoto, Kimitake Hayasaki

Publikováno v: The Astrophysical Journal, Vol 958, Iss 1, p 52 (2023)

Circinus X-1 (Cir X-1) is a neutron star binary with an elliptical orbit of 16.6 days. The source is unique for its extreme youth, providing a key to understanding early binary evolution. However, its X-ray variability is too complex to reach a clear

Externí odkaz: https://doaj.org/article/1528ce4f35fd4b4990fe18dec1ecaed8

Disk Wind–Driven Expanding Radio-emitting Shell in Tidal Disruption Events

Autor: Kimitake Hayasaki, Ryo Yamazaki

Publikováno v: The Astrophysical Journal, Vol 954, Iss 1, p 5 (2023)

We study the evolution of a nonrelativistically expanding thin shell in radio-emitting tidal disruption events (TDEs) based on a one-dimensional spherically symmetric model considering the effect of both a time-dependent mass-loss rate of the disk wi

Externí odkaz: https://doaj.org/article/76795234b0564f19a0c87a949607da93

Broadband X-Ray Observations of the 2018 Outburst of the Changing-Look Active Galactic Nucleus NGC 1566

Autor: Prantik Nandi, Arghajit Jana, Arka Chatterjee, Neeraj Kumari, Gaurava K. Jaisawal, Claudio Ricci, Sachindra Naik, Kimitake Hayasaki

Publikováno v: Jana, A, Kumari, N, Nandi, P, Naik, S, Chatterjee, A, Jaisawal, G K, Hayasaki, K & Ricci, C 2021, ' Broad-band X-ray observations of the 2018 outburst of the changing-look active galactic nucleus NGC 1566 ', Monthly Notices of the Royal Astronomical Society, vol. 507, no. 1, pp. 687-703 . https://doi.org/10.1093/mnras/stab2155

We study the nature of the changing-look Active Galactic Nucleus NGC 1566 during its June 2018 outburst. During the outburst, the X-ray intensity of the source rises up to ~25-30 times compared to its quiescent state intensity. We perform timing and

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ba6719aabcbae4addb2148fb113af9b3

Neutrinos from tidal disruption events

Autor: Kimitake Hayasaki

Publikováno v: Nature Astronomy. 5:436-437

Tidal disruption events are an excellent probe for supermassive black holes in distant inactive galaxies because they show bright multi-wavelength flares lasting several months to years. AT2019dsg presents the first potential association with neutrin

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e4f58a82e0940d48b0616f1181269e68
https://doi.org/10.1038/s41550-021-01309-z