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Il Nuovo Cimento C

, Volume 16, Issue 5, pp 663–667 | Cite as

Estimate of the black-hole mass in NGC 6814 from a relativistic accretion disk scenario

  • S. Campana
  • L. Stella
Article

Summary

By using a fully relativistic model for the spectral line produced by a Keplerian disk orbiting a Schwarzschild black hole, we study the temporal behaviour of the line intensity in response to a continuum variation at an extended central source. We compare our results with the observed properties of the Seyfert galaxy NGC 6814, whose X-ray flux has been observed to decrease by a factor of two in ≈ 50 s, while the iron line intensity variations lag continuum variations by 250 s, at the most. Taking the stationary values of the iron line centroid energy and width, and assuming that the line comes from high-ionisation stages of iron (as several indications suggest) we derive that the inner radius of the line-emitting region is between 6 and 30r g (r g =GM/c 2), the inclination is ≤40°, while the mass of the central object is constrained to 8·104 L 43<M<3.9·106 M (L 43 is the accretion luminosity in units of 1043 erg s−1).

PACS 98.70.Qy

X-ray sources 

PACS 95.30.Sf

Relativity and gravitation 

PACS 97.60.LF

Black holes 

PACS 98.50.Qm

Active nuclei 

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References

  1. [1]
    A. F. Tennant, R. Mushotzky, E. A. Boldt andJ. H. Swank:Astrophys. J.,251, 15 (1981).CrossRefADSGoogle Scholar
  2. [2]
    H. Kunieda, T. J. Turner, H. Awaki, K. Koyama, R. Mushotzky andY. Tsusaka:Nature,345, 786 (1990).CrossRefADSGoogle Scholar
  3. [3]
    T. J. Turner, C. Done, R. Mushotzky, G. Madejski andH. Kunieda:Astrophys. J.,391, 102 (1992).CrossRefADSGoogle Scholar
  4. [4]
    H. Kunieda, H. Awaki, K. Koyama, Y. Tawara, Y. Tsusaka, C. Done, R. Mushotzky, T. J. Turner, K. Leighly andS. Tsuruta: inIron Line Diagnostic in X-ray Sources, edited byA. Treves, G. C. Perola, L. Stella, (Springer-Verlag, 1991), p. 241.Google Scholar
  5. [5]
    M. Yamauchi, M. Matsuoka, N. Kawai andA. Yoshida:Astrophys. J.,395, 453 (1992).CrossRefADSGoogle Scholar
  6. [6]
    K. Chen andJ. P. Halpern:Astrophys. J.,344, 115 (1989).CrossRefADSGoogle Scholar
  7. [7]
    A. C. Fabian, M. J. Rees, L. Stella andN. E. White:Mon. Not. R. Astron. Soc.,238, 729 (1989).ADSGoogle Scholar
  8. [8]
    S. Campana andL. Stella:Mon. Not. R. Astron. Soc.,264, 395 (1993).ADSGoogle Scholar
  9. [9]
    S. Campana andL. Stella: in preparation.Google Scholar
  10. [10]
    I. M. George andA. C. Fabian:Mon. Not. R. Astron. Soc.,249, 352 (1991).ADSGoogle Scholar
  11. [11]
    G. Matt, G. C. Perola, L. Piro andL. Stella:Astron. Astrophys.,257, 63 (1992).ADSGoogle Scholar
  12. [12]
    T. J. Turner, C. Done, H. Kunieda, R. Mushotzky andH. Awaki: inStructure and Emission Properties of Accretion Disks, edited byC. Bertout, S. Collins, J. P. Lasota andJ. Tran Thanh Van (Editions Frontières, Gif-sur-Yvette, 1990), p. 545.Google Scholar
  13. [13]
    N. I. Shakura andR. A. Sunyaev:Astron. Astrophys.,24, 337 (1973).ADSGoogle Scholar

Copyright information

© Società Italiana di Fisica 1993

Authors and Affiliations

  • S. Campana
    • 1
  • L. Stella
    • 2
  1. 1.Università degli Studi di MilanoMilanoItalia
  2. 2.Osservatorio Astronomico di BreraMilanoItalia

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