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  • Letter
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Broad-line active galactic nuclei rotate faster than narrow-line ones

Abstract

The super-massive black holes of 106M to 109M that reside in the nuclei of active galaxies1 (AGN) are surrounded by a region emitting broad lines, probably associated with an accretion disk. The diameters of the broad-line regions range from a few light-days to more than a hundred light-days1, and cannot be resolved spatially. The relative significance of inflow, outflow, rotational or turbulent motions in the broad-line regions as well as their structure (spherical, thin or thick accretion disk) are unknown despite intensive studies over more than thirty years2,3. Here we report a fundamental relation between the observed emission linewidth full-width at half-maximum (FWHM) and the emission line shape FWHM/σline in AGN spectra. From this relation we infer that the predominant motion in the broad-line regions is Keplerian rotation in combination with turbulence. The geometry of the inner region varies systematically with the rotation velocity: it is flattest for the fast-rotating broad-line objects, whereas slow-rotating narrow-line AGN have a more spherical structure. Superimposed is the trend that the line-emitting region becomes geometrically thicker towards the centre within individual galaxies. Knowing the rotational velocities, we can derive the central black-hole masses more accurately; they are two to ten times smaller than has been estimated previously.

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Figure 1: Observed and modelled Hβ linewidth ratios FWHM/ σ line versus linewidth FWHM.
Figure 2: Observed and modelled He  ii λ = 4,686 Å linewidth ratios FWHM/ σ line versus linewidth FWHM.
Figure 3: Observed and modelled C  iv λ = 1,550 Å linewidth ratios FWHM/ σ line versus linewidth FWHM.

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References

  1. Peterson, B. M. et al. Central masses and broad-line region sizes of active galactic nuclei. II: A homogeneous analysis of a large reverberation-mapping database. Astrophys. J. 613, 682–699 (2004)

    Article  ADS  CAS  Google Scholar 

  2. Blumenthal, G. R. &. Mathews, W. G. Theoretical emission line profiles in QSOs and Seyfert galaxies. Astrophys. J. 198, 517–526 (1975)

    Article  ADS  Google Scholar 

  3. Sulentic, J. W., Marziani, P. & Dultzin-Hacyan, D. Phenomenology of broad emission lines in active galactic nuclei. Annu. Rev. Astron. Astrophys. 38, 521–571 (2000)

    Article  ADS  CAS  Google Scholar 

  4. Collin, S., Kawaguchi, T., Peterson, B. M. & Vestergaard, M. Systematic effects in measurement of black hole masses by emission-line reverberation of active galactic nuclei: Eddington ratio and inclination. Astron. Astrophys. 456, 75–90 (2006)

    Article  ADS  CAS  Google Scholar 

  5. Hubeny, I., Stefl, S. & Harmonec, P. How strong is the evidence of superionization and large mass outflows in B/Be stars? Bull. Astron. Inst. Czech. 36, 214–230 (1985)

    ADS  CAS  Google Scholar 

  6. Hubeny, I., Lanz, T. & Jeffrey, C. S. in Newsletter on Analysis of Astronomical Spectra No. 20 (ed. Jeffrey, C. S.) 30–42 (St Andrews University, 1994)

    Google Scholar 

  7. Kollatschny, W. Accretion disk wind in the AGN broad-line region: spectroscopically resolved line profile variations in Mrk 110. Astron. Astrophys. 407, 461–472 (2003)

    Article  ADS  CAS  Google Scholar 

  8. Peterson, B. M. & Wandel, A. Keplerian motion of broad-line region gas as evidence for supermassive black holes in active galactic nuclei. Astrophys. J. 521, L95–L98 (1999)

    Article  ADS  CAS  Google Scholar 

  9. Sulentic, J. W., Zwitter, T., Marziani, P. & Dultzin-Hacyan, D. Eigenvector 1: an optimal correlation space for active galactic nuclei. Astrophys. J. 536, L5–L9 (2000)

    Article  ADS  CAS  Google Scholar 

  10. Netzer, H. The largest black holes and the most luminous galaxies. Astrophys. J. 583, L5–L8 (2003)

    Article  ADS  Google Scholar 

  11. Netzer, H. et al. Black hole mass and growth rate at high redshift. Astrophys. J. 671, 1256–1263 (2007)

    Article  ADS  CAS  Google Scholar 

  12. Baskin, A. & Laor, A. What controls the CIV line profile in active galactic nuclei? Mon. Not. R. Astron. Soc. 356, 1029–1044 (2005)

    Article  ADS  CAS  Google Scholar 

  13. Pringle, J. E. Accretion discs in astrophysics. Annu. Rev. Astron. Astrophys. 19, 137–160 (1981)

    Article  ADS  Google Scholar 

  14. Zamfir, S., Sulentic, J. W., Marziani, P. & Dultzin, D. Detailed characterization of Hβ emission line profile in low-z SDSS quasars. Mon. Not. R. Astron. Soc. 403, 1759–1786 (2010)

    Article  ADS  CAS  Google Scholar 

  15. Bevington, P. R. & Robinson, D. K. Data Reduction and Error Analysis 2nd edn (McGraw-Hill, 1992)

    Google Scholar 

  16. Press, W. H., Teukolsky, S. A., Vetterling, W. T. & Flannery, B. P. Numerical Recipes 2nd edn (Cambridge University Press, 1992)

    MATH  Google Scholar 

  17. Blandford, R. D. Physical processes in active galactic nuclei. Saas-Fee Adv. Courses 20, 161–275 (1990)

    Article  ADS  Google Scholar 

  18. Elvis, M. A structure for quasars. Astrophys. J. 545, 63–76 (2000)

    Article  ADS  Google Scholar 

  19. Kollatschny, W. Spin orientation of supermassive black holes in active galaxies. Astron. Astrophys. 412, L61–L64 (2003)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We acknowledge discussions with W. Glatzel and S. Dreizler. This work has been supported by the Niedersachsen-Israel Research Cooperation Program ZN2318.

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W.K. had the basic ideas. M.Z. made the detailed model calculations. Both authors discussed the results at length.

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Correspondence to Wolfram Kollatschny.

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The authors declare no competing financial interests.

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Kollatschny, W., Zetzl, M. Broad-line active galactic nuclei rotate faster than narrow-line ones. Nature 470, 366–368 (2011). https://doi.org/10.1038/nature09761

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