Skip to main content
SpringerLink
Log in

Variability of Cyg X-1 (V1357 Cyg) in 1995–1996 during the hard and soft X-ray spectral states

  • Published:
Astronomy Letters Aims and scope Submit manuscript

Abstract

We report photoelectric UBVR observations of Cyg X-1 with the 1-m Tien-Shan and 48-cm Mount Maidanak reflectors from October 1995 through November 1996. The orbital light curve is represented by the model of a tidally deformed star. Various types of flare and fading are observed. The optical and X-ray (ASM/RXTE 2–10 keV) variabilities are compared. A 90-day soft X-ray outburst occurred in the summer of 1996, but no similar event was detected at optical wavelengths. Nevertheless, an interrelation was found between the variabilities in these bands, suggesting that they are affected by the same processes. A correlation between changes in the mean X-ray and optical fluxes was found after the 90-day X-ray outburst and the mean optical orbital light curve were subtracted. A Fourier analysis reveals common features in Fourier spectra of the X-ray and optical data. An orbital X-ray variability with a 5.6% amplitude is confirmed. Optical flares with a \(0_.^m 04\) amplitude and a duration of several days, which coincided with local X-ray minima, were detected. The optical brightness of Cyg X-1 declined by \(0_.^m 04\) in about a week early in November 1996. A possible physical interpretation of the flares and the orbital X-ray variability in terms of accretion instability is offered. The characteristic time it takes for matter to pass through the accretion structure is estimated directly from observations; it was approximately a week in 1996.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. J. C. Kemp, E. A. Karitskaya, M. I. Kumsiashvili, et al., Astron. Zh. 64, 326 (1987).

    ADS  Google Scholar 

  2. V. M. Lyutyi, R. A. Sunyaev, and A. M. Cherepashchuk, Astron. Zh. 50, 3 (1973).

    ADS  Google Scholar 

  3. V. V. Bruevich, N. N. Kilyachkov, R. A. Sunyaev, et al., Pis'ma Astron. Zh. 4, 292 (1978) [Sov. Astron. Lett. 4, 292 (1978)].

    Google Scholar 

  4. W. C. Priedhorsky, J. Terrell, and S. S. Holt, Astrophys. J. 270, 233 (1983).

    Article  ADS  Google Scholar 

  5. N. G. Bochkarev and E. A. Karitskaya, Adv. Space Res. 8(2-3), 205 (1988).

    ADS  Google Scholar 

  6. E. A. Karitskaya and N. G. Bochkarev, Var: Phenomena in Close Bin. Stars (Konkoly Obs. Hung. Akad. Sci., Budapest, 1989), Vol. 10, Part 7, No. 93, p. 255.

    Google Scholar 

  7. E. A. Karitskaya, Astron. Zh. 58, 146 (1981).

    ADS  Google Scholar 

  8. J. C. Kemp, L. C. Herman, R. J. Rudy, et al., Nature 270, 227 (1977).

    Article  ADS  Google Scholar 

  9. E. A. Karitskaya, Astron. Tsirk., No. 1088, 1 (1979).

    ADS  Google Scholar 

  10. V. M. Lyutyi, Astron. Zh. 62, 731 (1985).

    ADS  Google Scholar 

  11. E. N. Walker and A. R. Quintanilla, Mon. Not. R. Astron. Soc. 182, 315 (1978).

    ADS  Google Scholar 

  12. S. W. Zhang, B. A. Harmon, W. S. Paciesas, et al., IAU Circ. No. 6462 (1996).

  13. S. W. Zhang, C. R. Robinson, and W. Cui, IAU Circ. No. 6510 (1996).

  14. J. C. Kemp, M. S. Barbour, and R. E. McBirney, Astrophys. J. Lett. 244, L73 (1981).

    Article  ADS  Google Scholar 

  15. V. G. Kornilov and A. V. Krylov, Astron. Zh. 67, 173 (1990).

    ADS  Google Scholar 

  16. V. G. Kornilov, I. M. Volkov, A. I. Zakharov, et al., Trudy Gos. Astron. Inst. Sternberg 63 (1991).

  17. V. G. Kornilov, Balt. Astron. 7, 513 (1998).

    ADS  Google Scholar 

  18. V. M. Lyutyi, Perem. Zvezdy 18, 417 (1972).

    ADS  Google Scholar 

  19. V. P. Goranskii, E. A. Karitskaya, K. N. Grankin, et al., Inform. Bull. Var. Stars, No. 4682 (1999).

  20. G. Hill, R. W. Hilditch, and E. L. Pfannenschmidt, Victoria Obs. Publ. 15, 1 (1976).

    ADS  Google Scholar 

  21. A. A. Hoag, H. L. Johnson, B. Iriarte, et al., Naval Obs. Publ., Second series, 17, VII (1961).

    Google Scholar 

  22. A. V. Mironov, Precision Photometry (EDEM, Moscow, 1997), p. 67.

    Google Scholar 

  23. E. A. Karitskaya, Candidate's Dissertation (Moscow, 1981).

  24. N. G. Bochkarev, E. A. Karitskaya, and N. I. Shakura, Astron. Zh. 56, 16 (1979).

    ADS  Google Scholar 

  25. W. Cui, IAU Circ. No. 6404 (1996).

  26. E. A. Karitskaya and V. P. Goranskii, Inform. Bull. Var. Stars, No. 4404 (1996).

  27. I. B. Voloshina, V. M. Lyutyi, and A. E. Tarasov, Pis'ma Astron. Zh. 23, 335 (1997) [Astron. Lett. 23, 293 (1997)].

    ADS  Google Scholar 

  28. T. J. Deeming, Astrophys. Space Sci. 36, 173 (1975).

    Article  MathSciNet  Google Scholar 

  29. V. Yu. Terebizh, Analysis of Time Series in Astrophysics (Nauka, Moscow 1992).

    Google Scholar 

  30. V. P. Goranskii, V. F. Esipov, and A. M. Cherepashchuk, Astron. Zh. 75, 240 (1998).

    Google Scholar 

  31. E. A. Karitskaya, Izv. Ross. Akad. Nauk 62, 1787 (1998).

    Google Scholar 

  32. J. C. Kemp, Astrophys. J. 235, 595 (1980).

    Article  ADS  Google Scholar 

  33. B. Margon and S. Bowyer, Astrophys. J., Lett. 185, Ed. L113 (1973).

    Article  ADS  Google Scholar 

  34. V. Straizhis, Multicolor Stellar Photometry (Mokslas, Vilnius 1977).

    Google Scholar 

  35. N. G. Bochkarev and V. M. Lyutyi, Pis'ma Astron. Zh. 24, 330 (1998) [Astron. Lett. 24, 277 (1998)].

    ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya ul. 48, Moscow, 109017, Russia

    E. A. Karitskaya

  2. Sternberg Astronomical Institute, Universitetskii pr. 13, Moscow, 119899, Russia

    V. P. Goranskii

  3. Astronomical Institute, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan

    K. N. Grankin & S. Yu. Mel'nikov

Authors
  1. E. A. Karitskaya
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. V. P. Goranskii
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. K. N. Grankin
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. S. Yu. Mel'nikov
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

__________

Translated from Pis'ma v Astronomicheski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \) Zhurnal, Vol. 26, No. 1, 2000, pp. 27–40.

Original Russian Text Copyright © 2000 by Karitskaya, Goranski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \), Grankin, Mel'nikov.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Karitskaya, E.A., Goranskii, V.P., Grankin, K.N. et al. Variability of Cyg X-1 (V1357 Cyg) in 1995–1996 during the hard and soft X-ray spectral states. Astron. Lett. 26, 22–33 (2000). https://doi.org/10.1134/1.20365

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1134/1.20365

Keywords

Search

Navigation