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

Journal name:
Nature
Volume:
529,
Pages:
54–58
Date published:
DOI:
doi:10.1038/nature16452
Received
Accepted
Published online

Abstract

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 hours1. 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 source6 containing a black hole of nine solar masses7 (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 thought1. 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.

At a glance

Figures

  1. Overall multi-colour light curves during the 2015 outburst of V404 Cyg.
    Figure 1: Overall multi-colour light curves during the 2015 outburst of V404 Cyg.

    Shown are multi-colour light curves (B, V, R and I bands, and no filters) during BJD 2,457,189 to 2,457,202 (BJD 2,457,189 corresponds to 2015 June 15). It is clearly seen that dip-type oscillations (variations with recurrent sudden dips) were observed from the beginning to the end of the outburst. The horizontal axis shows BJD − 2,457,189. The significant periods of repetitive optical variations are indicated in grey and green shading for the ‘dip-type’ and ‘heartbeat-type’ oscillations, respectively.

  2. Short-term and large-amplitude optical variations having repeating structures in the 2015 outburst of V404 Cyg.
    Figure 2: Short-term and large-amplitude optical variations having repeating structures in the 2015 outburst of V404 Cyg.

    ad, Variations with characteristic patterns during BJD 2,457,193.6 to 2,457,194.0 (a), BJD 2,457,197.7 to 2,457,198.0 (b), BJD 2,457,198.6 to 2,457,198.9 (c) and BJD 2,457,200.34 to 2,457,200.6 (d). In a, b and c, there are gradual rises with increasing amplitudes of fluctuations followed by dips, during which fluctuations disappear. These variations are sometimes accompanied by spikes. The interval between two dips ranges from ~45 min to ~2.5 h. d, Repetitive small oscillations with high coherence at intervals of ~5 min. The shapes of these oscillations resemble those of GRS 1915+1053.

  3. Correlation between optical and X-ray fluctuations of V404 Cyg in the 2015 outburst.
    Figure 3: Correlation between optical and X-ray fluctuations of V404 Cyg in the 2015 outburst.

    The times covered in each panel are BJD 2,457,194.126 to 2,457,194.140 (a), BJD 2,457,197.050 to 2,457,197.065 (b), BJD 2,457,198.760 to 2,457,198.780 (c) and BJD 2,457,199.430 to 2,457,199.450 (d). In each panel, the left-hand y axis shows magnitude in bands I, R, V and B, and the right-hand y axis shows counts per second in the Swift/XRT 0.5–10 keV band. Panels a and b cover the fading and rising phases, respectively; panels c and d show the correlations of short-term fluctuations. When both X-ray and optical light strongly varied, the correlation is generally good (though note in a, c and d that optical dips lag behind X-ray dips). Navy blue error bars, ±1σ. We plot points without errors when errors are smaller than or comparable to the plotting symbols.

  4. The bolometric luminosity Lbol of V404 Cyg during the 2015 outburst.
    Figure 4: The bolometric luminosity Lbol of V404 Cyg during the 2015 outburst.

    It is normalized to the Eddington luminosity assuming a black hole mass of 9M. Black points, Swift/BAT survey data (15–50 keV); red points, from the public Target Opportunity release of INTEGRAL Imager on Board the Integral Satellite (IBIS)/CdTe array (ISGRI) monitoring (25–60 keV). Grey and green shadings represent respectively the periods of the ‘dip-type oscillations’ and the ‘heartbeat-type oscillations’. Black and red error bars, ±1σ.

  5. Optical and X-ray light curves of V404 Cyg during an outburst in 2015 June–July.
    Extended Data Fig. 1: Optical and X-ray light curves of V404 Cyg during an outburst in 2015 June–July.

    a, Overall multi-colour light curves and Swift/BAT light curves. The plotted points are averaged for every 0.67 days. b, An enlarged view of the shaded box in a (the first detection of short-term variations). On BJD 2,457,203, the mean magnitude dropped below V = 17.0. Superimposed on this rapid fading, the amplitude of variations became progressively smaller and smaller. After BJD 2,457,205, the mean magnitude seemed to be constant, and the outburst virtually ended.

  6. Additional examples of simultaneous optical and X-ray observations of V404 Cyg in the 2015 outburst.
    Extended Data Fig. 2: Additional examples of simultaneous optical and X-ray observations of V404 Cyg in the 2015 outburst.

    Data shown in Fig. 3 are excluded. a, b, Main panels, correlations on BJD 2,457,192 (a) and BJD 2,457,200 (b); right panels, Swift/XRT light curves on linear scales. Navy blue error bars, ±1σ.

  7. Example of the soft X-ray light curve and spectra during the dip-type oscillation in the 2015 outburst of V404 Cyg.
    Extended Data Fig. 3: Example of the soft X-ray light curve and spectra during the dip-type oscillation in the 2015 outburst of V404 Cyg.

    a, The ~860-s-long Swift/XRT raw light curve (BJD 2,457,194.125–2,457,194.135, ObsID 00031403040) without pile-up correction, same as the X-ray data in Fig. 3a. b, Time-sliced soft X-ray spectra with pile-up correction, in the intervals of T1 to T5 determined in a. The exposures of individual spectra are ~100–300 s. Error bars, ±1σ.

  8. Comparison of the 1938, 1989 and 2015 outbursts of V404 Cyg.
    Extended Data Fig. 4: Comparison of the 1938, 1989 and 2015 outbursts of V404 Cyg.

    The horizontal axis represents days BJD − 2,429,186, BJD − 2,447,673 and BJD − 2,457,189, respectively. Photographic magnitudes are approximately the same as B band.

  9. Power spectral densities of the early stage, the middle stage, and the later stage in the 2015 outburst of V404 Cyg.
    Extended Data Fig. 5: Power spectral densities of the early stage, the middle stage, and the later stage in the 2015 outburst of V404 Cyg.

    Power spectral densities of the fluctuations on BJD 2,457,193 (top, circles), BJD 2,457,196 (middle, triangles) and BJD 2,457,200 (bottom, rectangles). The abscissa and ordinate denote the frequency in Hz and the power in arbitrary units, respectively. For better visualization, the obtained spectrum is multiplied by 8 × 10−4 on BJD 2,457,196 and by 10−4 on BJD 2,457,200. ±1σ error bars obtained from relevant χ2 distributions of the power spectra.

  10. Simultaneous, extinction-corrected multi-wavelength SEDs of V404 Cyg.
    Extended Data Fig. 6: Simultaneous, extinction-corrected multi-wavelength SEDs of V404 Cyg.

    a, b, The intervals shown are BJD 2,457,199.431–2,457,199.446 (a) and BJD 2,457,191.519–2,457,191.524 (b). The optical (V and IC) fluxes are averaged over the intervals; error bars, s.e. The X-ray, U- and UW2-band data are obtained with Swift; error bars, ±1σ. The radio fluxes (open squares) are compiled from the RATAN-600 results at BJD 2,457,199.433 (ref. 68). The red solid and dotted lines show the contribution of emissions from the irradiated disk with Comptonization and from the companion star, respectively. The blue dashed line approximates the radio SED, which is extended to the optical bands for illustrative purposes.

Tables

  1. A log of photometric observations of the 2015 outburst of V404 Cyg
    Extended Data Table 1: A log of photometric observations of the 2015 outburst of V404 Cyg
  2. List of instruments for optical observations
    Extended Data Table 2: List of instruments for optical observations
  3. Basic information on objects showing violent short-term variations in outbursts
    Extended Data Table 3: Basic information on objects showing violent short-term variations in outbursts

Videos

  1. The “twinkles” of the 2015 June-July outburst of V404 Cyg
    Video 1: The “twinkles” of the 2015 June-July outburst of V404 Cyg
    This video shows the “twinkles” of a black hole (short-term and violent variations) in V404 Cyg on June 17 and 18 in 2015 with their image data and light curves. We use the images provided by LCO (Extended Data Table 1). We can see the “twinkles” of a black hole with the naked eyes using a moderate telescope.

References

  1. Janiuk, A. & Czerny, B. On different types of instabilities in black hole accretion discs: implications for X-ray binaries and active galactic nuclei. Mon. Not. R. Astron. Soc. 414, 21862194 (2011)
  2. Fender, R. P. & Belloni, T. GRS 1915+105 and the disc-jet coupling in accreting black hole systems. Annu. Rev. Astron. Astrophys. 42, 317364 (2004)
  3. Belloni, T., Klein-Wolt, M., Méndez, M., van der Klis, M. & van Paradijs, J. A model-independent analysis of the variability of GRS 1915+105. Astron. Astrophys. 355, 271290 (2000)
  4. Hynes, R. I. et al. The remarkable rapid X-ray, ultraviolet, optical and infrared variability in the black hole XTE J1118+480. Mon. Not. R. Astron. Soc. 345, 292310 (2003)
  5. Motch, C., Ilovaisky, S. A. & Chevalier, C. Discovery of fast optical activity in the X-ray source GX 339−4. Astron. Astrophys. 109, L1L4 (1982)
  6. Tanaka, Y. & Shibazaki, N. X-ray novae. Annu. Rev. Astron. Astrophys. 34, 607644 (1996)
  7. Khargharia, J., Froning, C. S. & Robinson, E. L. Near-infrared spectroscopy of low-mass X-ray binaries: accretion disk contamination and compact object mass determination in V404 Cyg and Cen X-4. Astrophys. J. 716, 11051117 (2010)
  8. Miller-Jones, J. C. A. et al. The first accurate parallax distance to a black hole. Astrophys. J. 706, L230L234 (2009)
  9. Makino, F. GS 2023+338. IAU Circ . 4782 (1989)
  10. Barthelmy, S. D. et al. Swift trigger 643949 is V404 Cyg. GRB Coord. Netw. Circ . 17929 (2015)
  11. Negoro, H. et al. MAXI/GSC detection of a new outburst from the Galactic black hole candidate GS 2023+338 (V* V404 Cyg). Astron. Telegr. 7646 (2015)
  12. Chen, Y. T. et al. TAOS early optical observations of V404 Cyg. Astron. Telegr. 7722 (2015)
  13. Golenetskii, S. et al. Konus-Wind observation of Galactic transient V404 Cyg in outburst. GRB Coord. Netw. Circ. 17938 (2015)
  14. Uemura, M. et al. Rapid optical fluctuations in the black hole binary V4641 Sagittarii. Publ. Astron. Soc. Jpn 54, L79L82 (2002)
  15. Z.  ycki, P. T., Done, C. & Smith, D. A. The 1989 May outburst of the soft X-ray transient GS 2023+338 (V404 Cyg). Mon. Not. R. Astron. Soc. 309, 561575 (1999)
  16. Belloni, T., Méndez, M., King, A. R., van der Klis, M. & van Paradijs, J. An unstable central disk in the superluminal black hole X-ray binary GRS 1915+105. Astrophys. J. 479, L145L148 (1997)
  17. Neilsen, J., Remillard, R. A. & Lee, J. C. The physics of the “heartbeat” state of GRS 1915+105. Astrophys. J. 737, 69108 (2011)
  18. Altamirano, D. et al. The faint “heartbeats” of IGR J17091−3624: an exceptional black hole candidate. Astrophys. J. 742, L17L23 (2011)
  19. Osaki, Y. Dwarf-nova outbursts. Publ. Astron. Soc. Pacif. 108, 3960 (1996)
  20. Steeghs, D. et al. The not-so-massive black hole in the microquasar GRS 1915+105. Astrophys. J. 768, 185191 (2013)
  21. Janiuk, A., Grzedzielski, M., Capitanio, F. & Bianchi, S. Interplay between heartbeat oscillations and wind outflow in microquasar IGR J17091−3624. Astron. Astrophys. 574, A92A102 (2015)
  22. Casares, J., Charles, P. A. & Naylor, T. A 6.5-day periodicity in the recurrent nova V404 Cygni implying the presence of a black hole. Nature 355, 614617 (1992)
  23. Orosz, J. A. et al. A black hole in the superluminal source SAX J1819.3−2525 (V4641 Sgr). Astrophys. J. 555, 489503 (2001)
  24. Bagnoli, T. & in’t Zand, J. J. M. Discovery of GRS 1915+105 variability patterns in the rapid burster. Mon. Not. R. Astron. Soc. 450, L52L56 (2015)
  25. Hameury, J.-M., Menou, K., Dubus, G., Lasota, J.-P. & Hure, J.-M. Accretion disc outbursts: a new version of an old model. Mon. Not. R. Astron. Soc. 298, 10481060 (1998)
  26. Panopoulou, G., Reig, P. & Blinov, D. Optical polarization of V404 Cyg. Astron. Telegr. 7674 (2015)
  27. Itoh, R. et al. Optical and near-infrared polarimetry for V404 Cyg with 1.6m Pirka and 1.5m Kanata telescopes in Japan. Astron. Telegr. 7709 (2015)
  28. Lasota, J.-P. The disc instability model of dwarf novae and low-mass X-ray binary transients. New Astron. Rev. 45, 449508 (2001)
  29. Kim, S.-W., Wheeler, J. C. & Mineshige, S. Disk instability and outburst properties of the intermediate polar GK Persei. Astrophys. J. 384, 269283 (1992)
  30. King, A. R. & Ritter, H. The light curves of soft X-ray transients. Mon. Not. R. Astron. Soc. 293, L42L48 (1998)
  31. Kato, T. et al. Variable Star Network: world center for transient object astronomy and variable stars. Publ. Astron. Soc. Jpn 56, S1S54 (2004)
  32. Muyllaert, E. V404 Cyg going into outburst!? BAAVSS Alert 4101 (2015); https://groups.yahoo.com/neo/groups/baavss-alert/conversations/messages/4101
  33. AAVSO American Association of Variable Star Observers. Download data. http://www.aavso.org/data-download/ (accessed 4 July 2015)
  34. Lehner, M. J. et al. The Taiwanese-American Occultation Survey: the multi-telescope robotic observatory. Publ. Astron. Soc. Pacif. 121, 138152 (2009)
  35. AAVSO American Association of Variable Star Observers. Variable star plotter. http://www.aavso.org/vsp (accessed 4 July 2015)
  36. Gandhi, P. et al. Correlated optical and X-ray variability in V404 Cyg. Astron. Telegr. 7727 (2015)
  37. Lewin, W. H. G. et al. The discovery of rapidly repetitive X-ray bursts from a new source in Scorpius. Astrophys. J. 207, L95L99 (1976)
  38. Bagnoli, T., in’t Zand, J. J. M., Galloway, D. K. & Watts, A. L. Indications for a slow rotator in the Rapid Burster from its thermonuclear bursting behaviour. Mon. Not. R. Astron. Soc. 431, 19471955 (2013)
  39. Goranskij, V. P. Variable stars in Sagittarius. Astronomicheskii Tsirkulyar 1024, 34 (1978)
  40. Samus, N. N. et al. V4641 Sagittarii and GM Sagittarii. IAU Circ. 7277 (1999)
  41. Stubbings, R. et al. GM Sagittarii and SAX J1819.3−2525 = XTE J1819−254. IAU Circ . 7253 (1999)
  42. Kato, T., Uemura, M., Stubbings, R., Watanabe, T. & Monard, B. Preoutburst activity of V4641 Sgr = SAX J1819.3−2525: possible existence of 2.5-day period. Inform. Bull. Variable Stars 4777 (1999)
  43. Hjellming, R. M. et al. Light curves and radio structure of the 1999 September transient event in V4641 Sagittarii (=XTE J1819−254 = SAX J1819.3−2525). Astrophys. J. 544, 977992 (2000)
  44. Uemura, M. et al. The 1999 optical outburst of the fast X-ray nova, V4641 Sagittarii. Publ. Astron. Soc. Jpn 54, 95101 (2002)
  45. Uemura, M. et al. Outburst and post-outburst active phase of the black hole X-ray binary, V4641 Sgr in 2002. Publ. Astron. Soc. Jpn 56, S61S75 (2004)
  46. Uemura, M. et al. Optical observation of the 2003 outburst of a black hole X-ray binary, V4641 Sagittarii. Publ. Astron. Soc. Jpn 56, 823829 (2004)
  47. Uemura, M. et al. Outburst of a black hole X-ray binary V4641 Sgr in 2004 July. Inform. Bull. Variable Stars 5626, 14 (2005)
  48. Revnivtsev, M., Sunyaev, R., Gilfanov, M. & Churazov, E. V4641 Sgr — a super-Eddington source enshrouded by an extended envelope. Astron. Astrophys. 385, 904908 (2002)
  49. Mirabel, I. F. & Rodrguez, L. F. Sources of relativistic jets in the Galaxy. Annu. Rev. Astron. Astrophys. 37, 409443 (1999)
  50. Imamura, J. N., Kristian, J., Middleditch, J. & Steiman-Cameron, T. Y. The 8 second optical quasi-periodic oscillations in GX 339−4. Astron. Astrophys. 365, 312316 (1990)
  51. Casares, J., Charles, P. A., Jones, D. H. P., Rutten, R. G. M. & Callanan, P. J. Optical studies of V404 Cyg, the X-ray transient GS 2023+338. I — the 1989 outburst and decline. Mon. Not. R. Astron. Soc. 250, 712725 (1991)
  52. Wagner, R. M. et al. Optical identification of the X-ray source GS 2023+338 as V404 Cygni. Astrophys. J. 378, 293297 (1991)
  53. Chevalier, C. & Ilovaisky, S. A. CCD photometry of GRO J0422+32 during activity and quiescence. Astron. Astrophys. 297, 103114 (1995)
  54. Whelan, J. A. J. et al. Spectroscopic observations of the X-ray nova A0620−00. Mon. Not. R. Astron. Soc. 180, 657673 (1977)
  55. Hynes, R. I., Robinson, E. L. & Morales, J. Rapid optical photometry of V404 Cyg. Astron. Telegr. 7677 (2015)
  56. Gandhi, P. et al. Sub-second multi-band optical timing of V404 Cyg with ULTRACAM. Astron. Telegr. 7686 (2015)
  57. Hynes, R. I., Robinson, E. L. & Morales, J. Further rapid optical photometry of V404 Cyg. Astron. Telegr. 7710 (2015)
  58. Cannizzo, J. K. On the relative rates of decay of the optical and soft X-ray fluxes in dwarf nova outbursts. Astrophys. J. 473, L41L44 (1996)
  59. Meyer, F. Transition waves in accretion disks. Astron. Astrophys. 131, 303308 (1984)
  60. Cannizzo, J. K., Smale, A. P., Wood, M. A., Still, M. D. & Howell, S. B. The Kepler light curves of V1504 Cygni and V344 Lyrae: a study of the outburst properties. Astrophys. J. 747, 117128 (2012)
  61. Savoury, C. D. J. et al. Cataclysmic variables below the period gap: mass determinations of 14 eclipsing systems. Mon. Not. R. Astron. Soc. 415, 20252041 (2011)
  62. Munoz-Darias, T., Sanchez, D. M. & Casares, J. Optical spectroscopy of V404 Cyg: evolution of the P Cygni profiles. Astron. Telegr. 7669 (2015)
  63. Caballero-Garcia, M. D., Castro-Tirado, A. J., Oates, S. & Jeong, S. Early optical spectroscopy follow-up of V404 Cyg with GTC/OSIRIS. Astron. Telegr. 7699 (2015)
  64. Scarpaci, J., Maitra, D., Hynes, R. & Markoff, S. Multi-band optical observations of V404 Cygni and correlated spectral changes. Astron. Telegr. 7737 (2015)
  65. Casares, J., Charles, P. A., Naylor, T. & Pavlenko, E. P. Optical studies of V404 Cygni the X-ray transient GS 2023+338 – part three – the secondary star and accretion disc. Mon. Not. R. Astron. Soc. 265, 834852 (1993)
  66. Cardelli, J. A., Clayton, G. C. & Mathis, J. S. The relationship between infrared, optical, and ultraviolet extinction. Astrophys. J. 345, 245256 (1989)
  67. Bohlin, R. C., Savage, B. D. & Drake, J. F. A survey of interstellar H I from Lα absorption measurements. II. Astrophys. J. 224, 132142 (1978)
  68. Trushkin, S. A., Nizhelskij, N. A. & Tybulev, P. G. The inverted radio spectrum of the flare in V404 Cyg. Astron. Telegr. 7667 (2015)
  69. Gies, D. R. et al. Stellar wind variations during the X-ray high and low states of Cygnus X-1. Astrophys. J. 678, 12371247 (2008)
  70. Kaptein, R. G. et al. Discovery of 1RXS J171824.2−402934 as an X-ray burster. Astron. Astrophys. 358, L71L74 (2000)
  71. Hynes, R. I. et al. The quiescent spectral energy distribution of V404 Cyg. Mon. Not. R. Astron. Soc. 399, 22392248 (2009)
  72. Osaki, Y. & Meyer, F. Early humps in WZ Sge stars. Astron. Astrophys. 383, 574579 (2002)
  73. Fender, R. P. Powerful jets from black hole X-ray binaries in low/hard X-ray states. Mon. Not. R. Astron. Soc. 322, 3142 (2001)
  74. Blandford, R. D. & Königl, A. Relativistic jets as compact radio sources. Astrophys. J. 232, 3448 (1979)
  75. Corbel, S. & Fender, R. P. Near-infrared synchrotron emission from the compact jet of GX 339−4. Astrophys. J. 573, L35L39 (2002)
  76. Gandhi, P. et al. A variable mid-infrared synchrotron break associated with the compact jet in GX 339−4. Astrophys. J. 740, L13L19 (2011)
  77. Russell, T. D. et al. The accretion-ejection coupling in the black hole candidate X-ray binary MAXI J1836−194. Mon. Not. R. Astron. Soc. 439, 13901402 (2014)
  78. INTEGRAL Science Data Centre. INTEGRAL data analysis. http://www.isdc.unige.ch/integral/analysis#QLAsources (8 August 2015)
  79. Wang, J. H. et al. Early optical brightening in GRB 071010B. Astrophys. J. 679, L5L8 (2008)
  80. Kloppenborg, B. K., Pieri, R., Eggenstein, H.-B., Maravelias, G. & Pearson, T. A demonstration of accurate wide-field V-band photometry using a consumer-grade DSLR camera. J. Am. Assoc. Variable Star Obs. 40, 815833 (2012)
  81. Alcock, C. et al. TAOS: The Taiwanese-American Occultation Survey. Earth Moon Planets 92, 459464 (2003)
  82. Zhang, Z.-W. et al. The TAOS project: results from seven years of survey data. Astron. J. 146, 1423 (2013)
  83. Casares, J. & Charles, P. A. Optical studies of V404 Cyg, the X-ray transient GS 2023+338. IV. the rotation speed of the companion star. Mon. Not. R. Astron. Soc. 271, L5L9 (1994)
  84. Wijnands, R., Yang, Y. J. & Altamirano, D. The enigmatic black hole candidate and X-ray transient IGR J17091−3624 in its quiescent state as seen with XMM-Newton. Mon. Not. R. Astron. Soc. 422, L91L95 (2012)
  85. Reid, M. J. et al. A parallax distance to the microquasar GRS 1915+105 and a revised estimate of its black hole mass. Astrophys. J. 796, 29 (2014)
  86. Iyer, N., Nandi, A. & Mandal, S. Determination of the mass of IGR J17091−3624 from “spectro-temporal” variations during the onset phase of the 2011 outburst. Astrophys. J. 807, 108116 (2015)
  87. Sala, G. et al. Constraints on the mass and radius of the accreting neutron star in the Rapid Burster. Astrophys. J. 752, 158164 (2012)
  88. MacDonald, R. K. D. et al. The black hole binary V4641 Sagitarii: activity in quiescence and improved mass determinations. Astrophys. J. 784, 220 (2014)
  89. Fender, R. P. et al. MERLIN observations of relativistic ejections from GRS 1915+105. Mon. Not. R. Astron. Soc. 304, 865876 (1999)
  90. King, A. L. et al. An extreme X-ray disk wind in the black hole candidate IGR J17091−3624. Astrophys. J. 746, L20L24 (2012)
  91. Szkody, P. et al. V404 Cygni. IAU Circ. 4794 (1989)

Download references

Author information

Affiliations

  1. Department of Astronomy, Graduate School of Science, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan

    • Mariko Kimura,
    • Keisuke Isogai,
    • Taichi Kato,
    • Yoshihiro Ueda,
    • Teruaki Enoto,
    • Takafumi Hori &
    • Daisaku Nogami
  2. JEM Mission Operations and Integration Center, Human Spaceflight Technology Directorate, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan.

    • Satoshi Nakahira
  3. MAXI team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.

    • Megumi Shidatsu
  4. The Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8302, Japan.

    • Teruaki Enoto
  5. Astronomy Department, Wesleyan University, Middletown, Connecticut 06459, USA.

    • Colin Littlefield
  6. Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.

    • Ryoko Ishioka,
    • Ying-Tung Chen,
    • Sun-Kun King,
    • Chih-Yi Wen,
    • Shiang-Yu Wang,
    • Matthew J. Lehner,
    • Megan E. Schwamb,
    • Jen-Hung Wang,
    • Zhi-Wei Zhang,
    • Kem H. Cook &
    • Typhoon Lee
  7. Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19125, USA.

    • Matthew J. Lehner
  8. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.

    • Matthew J. Lehner &
    • Charles Alcock
  9. Steward Observatory, University of Arizona, Tucson, Arizona 85721, USA

    • Tim Axelrod
  10. Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, New York 10003, USA

    • Federica B. Bianco
  11. Department of Astronomy and University Observatory, Yonsei University, Seoul 120-749, South Korea

    • Yong-Ik Byun
  12. Institute of Astronomy and Department of Physics, National Central University, Chung-Li 32054, Taiwan

    • Wen-Ping Chen
  13. Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany

    • Dae-Won Kim
  14. Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University, 452 Lomita Mall, Stanford, California 94309, USA

    • Stuart L. Marshall
  15. Crimean Astrophysical Observatory, 298409 Nauchny, Crimea

    • Elena P. Pavlenko,
    • Oksana I. Antonyuk,
    • Kirill A. Antonyuk,
    • Nikolai V. Pit,
    • Aleksei A. Sosnovskij,
    • Julia V. Babina,
    • Aleksei V. Baklanov &
    • Sergei P. Belan
  16. Space Research Institute, Russian Academy of Sciences, 117997 Moscow, Russia

    • Alexei S. Pozanenko,
    • Elena D. Mazaeva &
    • Alina A. Volnova
  17. National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia

    • Alexei S. Pozanenko
  18. Leibniz Institute for Astrophysics, Potsdam, Germany

    • Sergei E. Schmalz
  19. Fesenkov Astrophysical Institute, Almaty, Kazakhstan

    • Inna V. Reva
  20. Kharadze Abastumani Astrophysical Observatory, Ilia State University, Tbilisi, Georgia.

    • Raguli Ya. Inasaridze
  21. Institute of Astronomy and Geophysics, Mongolian Academy of Sciences, Ulaanbaatar 13343, Mongolia

    • Namkhai Tungalag
  22. Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, Russia

    • Igor E. Molotov
  23. Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva, Spain

    • Enrique de Miguel
  24. Center for Backyard Astrophysics, Observatorio del CIECEM, Parque Dunar, Matalascañas, 21760 Almonte, Huelva, Spain

    • Enrique de Miguel
  25. Baselstrasse 133D, CH-4132 Muttenz, Switzerland

    • Kiyoshi Kasai
  26. 6025 Calle Paraiso, Las Cruces, New Mexico 88012, USA

    • William L. Stein
  27. Vihorlat Observatory, Mierova 4, Humenne, Slovakia

    • Pavol A. Dubovsky
  28. Variable Star Observers League in Japan (VSOLJ), 7-1 Kitahatsutomi, Kamagaya, Chiba 273-0126, Japan

    • Seiichiro Kiyota
  29. Furzehill House, Ilston, Swansea SA2 7LE, UK

    • Ian Miller
  30. Physics Department, Rochester Institute of Technology, Rochester, New York 14623, USA

    • Michael Richmond
  31. American Association of Variable Star Observers (AAVSO), 13508 Monitor Lane, Sutter Creek, California 95685, USA

    • William Goff
  32. Institute of Astronomy, Russian Academy of Sciences, 361605 Peak Terskol, Kabardino-Balkaria, Russia

    • Maksim V. Andreev
  33. International Center for Astronomical, Medical and Ecological Research of National Academy of Sciences of Ukraine (NASU), 27 Akademika Zabolotnoho street, 03680 Kiev, Ukraine

    • Maksim V. Andreev
  34. Department of Physical Science, School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan

    • Hiromitsu Takahashi
  35. Osaka Kyoiku University, 4-698-1 Asahigaoka, Kashiwara, Osaka 582-8582, Japan

    • Naoto Kojiguchi,
    • Yuki Sugiura,
    • Nao Takeda,
    • Eiji Yamada &
    • Katsura Matsumoto
  36. 1 Tavistock Road, Chelmsford, Essex CM1 6JL, UK

    • Nick James
  37. The British Astronomical Association, Variable Star Section (BAA VSS), Burlington House, Piccadilly, London W1J 0DU, UK

    • Roger D. Pickard
  38. 3 The Birches, Shobdon, Leominster, Herefordshire HR6 9NG, UK

    • Roger D. Pickard
  39. Polaris Observatory, Hungarian Astronomical Association, Laborc utca 2/c, 1037 Budapest, Hungary

    • Tamás Tordai
  40. 112-14 Kaminishiyama-machi, Nagasaki, Nagasaki 850-0006, Japan

    • Yutaka Maeda
  41. Observatorio de Cantabria, Carretera de Rocamundo sin número, Valderredible, Cantabria, Spain

    • Javier Ruiz
  42. Instituto de Fisica de Cantabria (CSIC-UC), Avenida Los Castros sin número, E-39005 Santander, Cantabria, Spain

    • Javier Ruiz
  43. Agrupacion Astronomica Cantabra, Apartado 573, 39080 Santander, Spain

    • Javier Ruiz
  44. Seikei Meteorological Observatory, Seikei High School, Kichijoji-kitamachi 3-10-13, Musashino, Tokyo 180-8633, Japan

    • Atsushi Miyashita
  45. Center for Backyard Astrophysics (Concord), 1730 Helix Court, Concord, California 94518, USA

    • Lewis M. Cook
  46. Kwasan and Hida Observatories, Kyoto University, Kitakazan-Ohmine-cho, Yamashina-ku, Kyoto 607-8471, Japan

    • Akira Imada
  47. Hiroshima Astrophysical Science Center, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan

    • Makoto Uemura

Contributions

M.K. led the campaign, performed optical data analysis and compiled all optical data. K.I. and A.I. performed optical data analysis. T.K., Y.U., D.N. and M.U. contributed to science discussions. S.N., M.S., T.E., T.H. and H.T. performed X-ray data analysis. Other authors than those mentioned above performed optical observations. M.K., K.I., T.K., Y.U., S.N., T.E., M.S. and A.I. wrote the manuscript. T.K., Y.U. and D.N. supervised this project. M.K., K.I., T.K., Y.U., T.E., M.S., D.N., C.L., R.I., M.J.L., F.B.B., D.K., E.P.P., A.S.P., I.E.M., M.R., E.M., W.L.S., S.K., L.M.C., A.I. and M.U. improved the manuscript. All authors have read and approved the manuscript.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Reprints and permissions information is available at www.nature.com/reprints.

Author details

Extended data figures and tables

Extended Data Figures

  1. Extended Data Figure 1: Optical and X-ray light curves of V404 Cyg during an outburst in 2015 June–July. (796 KB)

    a, Overall multi-colour light curves and Swift/BAT light curves. The plotted points are averaged for every 0.67 days. b, An enlarged view of the shaded box in a (the first detection of short-term variations). On BJD 2,457,203, the mean magnitude dropped below V = 17.0. Superimposed on this rapid fading, the amplitude of variations became progressively smaller and smaller. After BJD 2,457,205, the mean magnitude seemed to be constant, and the outburst virtually ended.

  2. Extended Data Figure 2: Additional examples of simultaneous optical and X-ray observations of V404 Cyg in the 2015 outburst. (384 KB)

    Data shown in Fig. 3 are excluded. a, b, Main panels, correlations on BJD 2,457,192 (a) and BJD 2,457,200 (b); right panels, Swift/XRT light curves on linear scales. Navy blue error bars, ±1σ.

  3. Extended Data Figure 3: Example of the soft X-ray light curve and spectra during the dip-type oscillation in the 2015 outburst of V404 Cyg. (165 KB)

    a, The ~860-s-long Swift/XRT raw light curve (BJD 2,457,194.125–2,457,194.135, ObsID 00031403040) without pile-up correction, same as the X-ray data in Fig. 3a. b, Time-sliced soft X-ray spectra with pile-up correction, in the intervals of T1 to T5 determined in a. The exposures of individual spectra are ~100–300 s. Error bars, ±1σ.

  4. Extended Data Figure 4: Comparison of the 1938, 1989 and 2015 outbursts of V404 Cyg. (266 KB)

    The horizontal axis represents days BJD − 2,429,186, BJD − 2,447,673 and BJD − 2,457,189, respectively. Photographic magnitudes are approximately the same as B band.

  5. Extended Data Figure 5: Power spectral densities of the early stage, the middle stage, and the later stage in the 2015 outburst of V404 Cyg. (159 KB)

    Power spectral densities of the fluctuations on BJD 2,457,193 (top, circles), BJD 2,457,196 (middle, triangles) and BJD 2,457,200 (bottom, rectangles). The abscissa and ordinate denote the frequency in Hz and the power in arbitrary units, respectively. For better visualization, the obtained spectrum is multiplied by 8 × 10−4 on BJD 2,457,196 and by 10−4 on BJD 2,457,200. ±1σ error bars obtained from relevant χ2 distributions of the power spectra.

  6. Extended Data Figure 6: Simultaneous, extinction-corrected multi-wavelength SEDs of V404 Cyg. (103 KB)

    a, b, The intervals shown are BJD 2,457,199.431–2,457,199.446 (a) and BJD 2,457,191.519–2,457,191.524 (b). The optical (V and IC) fluxes are averaged over the intervals; error bars, s.e. The X-ray, U- and UW2-band data are obtained with Swift; error bars, ±1σ. The radio fluxes (open squares) are compiled from the RATAN-600 results at BJD 2,457,199.433 (ref. 68). The red solid and dotted lines show the contribution of emissions from the irradiated disk with Comptonization and from the companion star, respectively. The blue dashed line approximates the radio SED, which is extended to the optical bands for illustrative purposes.

Extended Data Tables

  1. Extended Data Table 1: A log of photometric observations of the 2015 outburst of V404 Cyg (764 KB)
  2. Extended Data Table 2: List of instruments for optical observations (455 KB)
  3. Extended Data Table 3: Basic information on objects showing violent short-term variations in outbursts (119 KB)

Supplementary information

Video

  1. Video 1: The “twinkles” of the 2015 June-July outburst of V404 Cyg (5.86 MB, Download)
    This video shows the “twinkles” of a black hole (short-term and violent variations) in V404 Cyg on June 17 and 18 in 2015 with their image data and light curves. We use the images provided by LCO (Extended Data Table 1). We can see the “twinkles” of a black hole with the naked eyes using a moderate telescope.

Comments

  1. Report this comment #67485

    Mariko Kimura said:

    In Extended Data Table 1, the data having provided by KW2 (H. Maehara) on JD 2,457,190 are upper limits. In addition, "Wnm (K. Hirosawa)" in the index "Observer's code" of the caption of the table is wrong. "Wnm (M. Watanabe)" is correct. Furthermore, the observer's code "Ioh (H. Itoh)" is missing in the same index.
    We also thank M. Watanabe and H. Itoh.

Subscribe to comments

Additional data