Letter | Published:

Relativistic boost as the cause of periodicity in a massive black-hole binary candidate

Nature volume 525, pages 351353 (17 September 2015) | Download Citation

Abstract

Because most large galaxies contain a central black hole, and galaxies often merge1, black-hole binaries are expected to be common in galactic nuclei2. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries3,4,5, most recently in PG 1302-102, which has a short rest-frame optical period of four years (ref. 6). If the orbital period of the black-hole binary matches this value, then for the range of estimated black-hole masses, the components would be separated by 0.007–0.017 parsecs, implying relativistic orbital speeds. There has been much debate over whether black-hole orbits could be smaller than one parsec (ref. 7). Here we report that the amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival ultraviolet data. Follow-up ultraviolet and optical observations in the next few years can further test this prediction and confirm the existence of a binary black hole in the relativistic regime.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    & Coevolution (or not) of supermassive black holes and host galaxies. Annu. Rev. Astron. Astrophys. 51, 511–653 (2013)

  2. 2.

    , & Massive black hole binaries in active galactic nuclei. Nature 287, 307–309 (1980)

  3. 3.

    Observational evidence for binary black holes and active double nuclei. Mem. Soc. Astron. Ital. 77, 733–741 (2006)

  4. 4.

    et al. A massive binary black-hole system in OJ 287 and a test of general relativity. Nature 452, 851–853 (2008)

  5. 5.

    et al. A periodically varying luminous quasar at z = 2 from the Pan-STARRS1 Medium Deep Survey: a candidate supermassive black hole binary in the gravitational wave-driven regime. Astrophys. J. 803, L16 (2015)

  6. 6.

    et al. A possible close supermassive black-hole binary in a quasar with optical periodicity. Nature 518, 74–76 (2015)

  7. 7.

    & in The Astrophysics of Gravitational Wave Sources, AIP Conf. Proc. (eds & ) 686, 201–210 (AIP, 2003)

  8. 8.

    , & A supermassive binary black hole with triple disks. Astrophys. J. 682, 1134–1140 (2008)

  9. 9.

    , , & Three-dimensional magnetohydrodynamic simulations of circumbinary accretion disks: disk structures and angular momentum transport. Astrophys. J. 749, 118 (2012)

  10. 10.

    et al. Evolution of binary black holes in self gravitating discs. Dissecting the torques. Astron. Astrophys. 545, A127 (2012)

  11. 11.

    , & Accretion into the central cavity of a circumbinary disc. Mon. Not. R. Astron. Soc. 436, 2997–3020 (2013)

  12. 12.

    , & Tearing up the disc: misaligned accretion on to a binary. Mon. Not. R. Astron. Soc. 434, 1946–1954 (2013)

  13. 13.

    , , & Binary black hole accretion from a circumbinary disk: gas dynamics inside the central cavity. Astrophys. J. 783, 134 (2014)

  14. 14.

    , & Precession and accretion in circumbinary discs: the case of HD 104237. Mon. Not. R. Astron. Soc. 448, 3545–3554 (2015)

  15. 15.

    & Three-dimensional MHD simulation of circumbinary accretion disks. II. Net accretion rate. Astrophys. J. 807, 131 (2015)

  16. 16.

    & Periodic flux variability of stars due to the reflex Doppler effect induced by planetary companions. Astrophys. J. 588, L117–L120 (2003)

  17. 17.

    et al. Observations of Doppler boosting in Kepler light curves. Astrophys. J. 715, 51–58 (2010)

  18. 18.

    & Detection of the ellipsoidal and the relativistic beaming effects in the CoRoT-3 lightcurve. Astron. Astrophys. 521, L59 (2010)

  19. 19.

    et al. A ground-based measurement of the relativistic beaming effect in a detached double white dwarf binary. Astrophys. J. 725, L200–L204 (2010)

  20. 20.

    et al. Exploring the variable sky with the Catalina Real-time Transient Survey. In The First Year of MAXI: Monitoring Variable X-ray Sources (eds & ) 32 (MAXI, 2010)

  21. 21.

    , & The assembly and merging history of supermassive black holes in hierarchical models of galaxy formation. Astrophys. J. 582, 559–573 (2003)

  22. 22.

    , , , & A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302–102? Mon. Not. R. Astron. Soc. 452, 2540–2545 (2015)

  23. 23.

    & in Planets, Stars and Stellar Systems Vol. 3 (eds et al.) 489–540 (Springer, 2013)

  24. 24.

    , & Are the variations in quasar optical flux driven by thermal fluctuations? Astrophys. J. 698, 895–910 (2009)

  25. 25.

    & An eccentric circumbinary accretion disk and the detection of binary massive black holes. Astrophys. J. 672, 83–93 (2008)

  26. 26.

    , , , & Multiple periods in the variability of the supermassive black hole binary candidate quasar PG1302-102? Mon. Not. R. Astron. Soc. Lett. (in the press)

  27. 27.

    et al. Spectral energy distributions and multiwavelength selection of type 1 quasars. Astrophys. J. 166 (Suppl.), 470–497 (2006)

  28. 28.

    & Observational constraints on growth of massive black holes. Mon. Not. Astron. R. Soc. 335, 965–976 (2002)

  29. 29.

    & Black holes in binary systems. Observational appearance. Astron. Astrophys. 24, 337–355 (1973)

  30. 30.

    , & A global three-dimensional radiation magneto-hydrodynamic simulation of super-Eddington accretion disks. Astrophys. J. 796, 106 (2014)

  31. 31.

    & Advection-dominated accretion and the black hole event horizon. New Astron. Rev. 51, 733–751 (2008)

  32. 32.

    Scaling laws for advection-dominated flows: applications to low-luminosity galactic nuclei. Astrophys. J. 477, 585–601 (1997)

  33. 33.

    , & in Theory of Black Hole Accretion Disks (eds et al.) 148–182 (Cambridge Univ. Press, 1998)

  34. 34.

    , , & Correlated optical and radio structure in the QSO 1302-102. Publ. Astron. Soc. Pac. 106, 642–645 (1994)

  35. 35.

    , & The central engines of radio-loud quasars. Astron. Astrophys. 409, 887–898 (2003)

  36. 36.

    & Time-dependent models for the afterglows of massive black hole mergers. Astrophys. J. 714, 404–422 (2010)

  37. 37.

    & Dynamics of binary-disk interaction. 1. Resonances and disk gap sizes. Astrophys. J. 421, 651–667 (1994)

  38. 38.

    et al. Quantifying quasar variability as part of a general approach to classifying continuously varying sources. Astrophys. J. 708, 927–945 (2010)

  39. 39.

    , & Assessment of stochastic and deterministic models of 6304 quasar lightcurves from SDSS Stripe 82. Astron. Astrophys. 554, A137 (2013)

  40. 40.

    , , & emcee: the MCMC hammer. Publ. Astron. Soc. Pac. 125, 306–312 (2013)

  41. 41.

    & Bayes factors. J. Am. Stat. Assoc. 90, 773–795 (1995)

  42. 42.

    Star-disc-binary interactions in protoplanetary disc systems and primordial spin-orbit misalignments. Mon. Not. R. Astron. Soc. 440, 3532–3544 (2014)

  43. 43.

    , & Observational signatures of binary supermassive black holes. Astrophys. J. 785, 115 (2014)

  44. 44.

    & A complete atlas of recalibrated Hubble Space Telescope Faint Object Spectrograph spectra of active galactic nuclei and auasars. I. Pre-COSTAR spectra. Astrophys. J. 150 (Suppl.), 73–164 (2004)

  45. 45.

    , , , & Characterizing the low-redshift intergalactic medium toward PKS 1302–102. Astrophys. J. 676, 262–285 (2008)

Download references

Acknowledgements

The authors thank M. Graham, J. Halpern, A. Price-Whelan, J. Andrews, M. Charisi, E. Quataert, and B. Kocsis for discussions. We also thank M. Graham for providing the optical data in electronic form. This work was supported by the National Science Foundation Graduate Research Fellowship under grant no. DGE1144155 (D.J.D.) and by the NASA grant NNX11AE05G (Z.H.).

Author information

Affiliations

  1. Department of Astronomy, Columbia University, 550 West 120th Street, New York, New York 10027, USA

    • Daniel J. D'Orazio
    • , Zoltán Haiman
    •  & David Schiminovich

Authors

  1. Search for Daniel J. D'Orazio in:

  2. Search for Zoltán Haiman in:

  3. Search for David Schiminovich in:

Contributions

Z.H. conceived and supervised the project, performed the orbital velocity calculations, and wrote the first draft of the paper. D.J.D. computed the emission models and performed the fits to the observed light curve. D.S. analysed the archival UV data. All authors contributed to the text.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Zoltán Haiman.

Extended data

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature15262

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.