Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101830

Title:	Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni
Authors:	陳文屏;Kimura, Mariko;Isogai, Keisuke;Kato, Taichi;Ueda, Yoshihiro;Nakahira, Satoshi;Shidatsu, Megumi;Enoto, Teruaki;Hori, Takafumi;Nogami, Daisaku;Littlefield, Colin;Ishioka, Ryoko;Chen, Ying-Tung;King, Sun-Kun;Wen, Chih-Yi;Wang, Shiang-Yu;Lehner, Matthew J.;Schwamb, Megan E.;Wang, Jen-Hung;Zhang, Zhi-Wei;Alcock, Charles;Axelrod, Tim;Bianco, Federica B.;Byun, Yong-Ik;Chen, Wen-Ping;Cook, Kem H.;Kim, Dae-Won;Lee, Typhoon;Marshall, Stuart L.;Pavlenko, Elena P.;Antonyuk, Oksana I.;Antonyuk, Kirill A.;Pit, Nikolai V.;Sosnovskij, Aleksei A.;Babina, Julia V.;Baklanov, Aleksei V.;Pozanenko, Alexei S.;Mazaeva, Elena D.;Schmalz, Sergei E.;Reva, Inna V.;Belan, Sergei P.;Inasaridze, Raguli Ya;Tungalag, Namkhai;Volnova, Alina A.;Molotov, Igor E.;Miguel, Enrique de;Kasai, Kiyoshi;Stein, William L.;Dubovsky, Pavol A.;Kiyota, Seiichiro;Miller, Ian;Richmond, Michael;Goff, William;Andreev, Maksim V.;Takahashi, Hiromitsu;Kojiguchi, Naoto;Sugiura, Yuki;Takeda, Nao;Yamada, Eiji;Matsumoto, Katsura;James, Nick;Pickard, Roger D.;Tordai, Tamás;Maeda, Yutaka;Ruiz, Javier;Miyashita, Atsushi;Cook, Lewis M.;Imada, Akira;Uemura, Makoto
Contributors:	理學院天文研究所
Keywords:	639/33/34/864;639/33/34/867;Accretion;Accretion disks;Analysis;Astrophysics;Black holes;Fluctuations (Physics);Humanities and Social Sciences;letter;Light;multidisciplinary;Science;Spectrometer;Telescopes
Date:	2016-01-06
Issue Date:	2026-04-21 14:46:57 (UTC+8)
Publisher:	Nature Publishing Group;London: Nature Publishing Group UK
Abstract:	摘要： How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disk, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours 1 . In fact, such oscillations have been observed only in sources with a high mass-accretion rate, such as GRS 1915+105 (refs 2 , 3 ). These large-amplitude, relatively slow timescale, phenomena are thought to have physical origins distinct from those of X-ray or optical variations with small amplitudes and fast timescales (less than about 10 seconds) often observed in other black-hole binaries—for example, XTE J1118+480 (ref. 4 ) and GX 339−4 (ref. 5 ). Here we report an extensive multi-colour optical photometric data set of V404 Cygni, an X-ray transient source 6 containing a black hole of nine solar masses 7 (and a companion star) at a distance of 2.4 kiloparsecs (ref. 8 ). Our data show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates more than ten times lower than previously thought 1 . This suggests that the accretion rate is not the critical parameter for inducing inner-disk instabilities. Instead, we propose that a long orbital period is a key condition for these large-amplitude oscillations, because the outer part of the large disk in binaries with long orbital periods will have surface densities too low to maintain sustained mass accretion to the inner part of the disk. The lack of sustained accretion—not the actual rate—would then be the critical factor causing large-amplitude oscillations in long-period systems. Observations of V404 Cygni, an X-ray transient containing a black hole of nine solar masses and a companion star, show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates at least ten times lower than previously thought, suggesting that the accretion rate is not the critical parameter for inducing inner-disk instabilities. Violent variations from a black hole in visual light Observations of V404 Cygni, an X-ray transient containing a black hole of nine solar masses and a companion star, show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates at least 10 times slower than previously thought, suggesting that the accretion rate is not the critical parameter for inducing inner-disk instabilities. The authors propose that a long orbital period is a key condition, because the outer part of the disc will have surface densities too low to maintain sustained mass accretion to the inner part of the disc. The lack of sustained accretion — rather than the actual rate — would then be the critical factor causing violent oscillations in long-period systems. 其他題名： Nature 出版者： London: Nature Publishing Group UK 出版日期： 2016-01-07 出處： Nature (London), 2016-01, Vol.529 (7584), p.54-58 資源來源： SpringerLink Journals 版權： Springer Nature Limited 2016 版權： COPYRIGHT 2016 Nature Publishing Group 版權： Copyright Nature Publishing Group Jan 7, 2016 識別號： ISSN: 0028-0836 識別號： EISSN: 1476-4687 識別號： DOI: 10.1038/nature16452 識別號： PMID: 26738590 識別號： CODEN: NATUAS
Appears in Collections:	[Graduate Institute of Astronomy] journal & Dissertation

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