Supermassive black holes reside in the nuclei of most galaxies. During their active episodes, black holes are powered by accretion discs where gravitational energy is converted into radiation1. Accurately determining black hole masses is key to understand how the population evolves over time and how the black holes relate to their host galaxies2,3,4. Beyond the local universe, z ≳ 0.2, the mass is commonly estimated assuming a virialized motion of gas in the close vicinity of the active black holes, traced through broad emission lines5,6. However, this procedure has uncertainties associated with the unknown distribution of the gas clouds. Here, we show that the black hole masses derived from the properties of the accretion disk and virial mass estimates differ by a factor that is inversely proportional to the width of the broad emission lines. This leads to virial mass misestimations up to a factor of six. Our results suggest that a planar gas distribution that is inclined with respect to the line of sight may account for this effect. However, radiation pressure effects on the distribution of gas can also reproduce our results. Regardless of the physical origin, our findings contribute to mitigating the uncertainties in current black hole mass estimations and, in turn, will help us to better understand the evolution of distant supermassive black holes and their host galaxies.
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Shakura, N. I. & Sunyaev, R. A. Black holes in binary systems. Observational appearance. Astron. Astrophys. 24, 337–355 (1973).
Ferrarese, L. & Merritt, D. A fundamental relation between supermassive black holes and their host galaxies. Astrophys. J. 539, L9–L12 (2000).
Xiao, T. et al. Exploring the low-mass end of the M BH -σ * relation with active galaxies. Astrophys. J. 739, 28 (2011).
Kormendy, J. & Ho, L. C. Coevolution (or not) of supermassive black holes and host galaxies. Annu. Rev. Astron. Astrophys. 51, 511–653 (2013).
Trakhtenbrot, B. & Netzer, H. Black hole growth to z = 2—I. Improved virial methods for measuring M BH and L/L Edd. Mon. Not. R. Astron. Soc. 427, 3081–3102 (2012).
Shen, Y. The mass of quasars. Bull. Astron. Soc. India 41, 61–115 (2013).
Kaspi, S. et al. Reverberation measurements for 17 quasars and the size–mass–luminosity relations in active galactic nuclei. Astrophys. J. 533, 631–649 (2000).
Bentz, M. C. et al. The low-luminosity end of the radius–luminosity relationship for active galactic nuclei. Astrophys. J. 767, 149 (2013).
Onken, C. A. et al. Supermassive black holes in active galactic nuclei. II. Calibration of the black hole mass–velocity dispersion relationship for active galactic nuclei. Astrophys. J. 615, 645–651 (2004).
Graham, A. W. in Galactic Bulges (eds Laurikainen, E., Peletier, R. & Gadotti, D.) 263–313 (Springer, 2016).
Woo, J.-H., Yoon, Y., Park, S., Park, D. & Kim, S. C. The black hole mass–stellar velocity dispersion relation of narrow-LINE Seyfert 1 galaxies. Astrophys. J. 801, 38 (2015).
Marconi, A. et al. The effect of radiation pressure on virial black hole mass estimates and the case of narrow-line Seyfert 1 galaxies. Astrophys. J. 678, 693–700 (2008).
Netzer, H. & Marziani, P. The effect of radiation pressure on emission-line profiles and black hole mass determination in active galactic nuclei. Astrophys. J. 724, 318–328 (2010).
Denney, K. D. et al. Diverse kinematic signatures from reverberation mapping of the broad-line region in AGNs. Astrophys. J. 704, L80–L84 (2009).
Denney, K. D. et al. Reverberation mapping measurements of black hole masses in six local Seyfert galaxies. Astrophys. J. 721, 715–737 (2010).
Gaskell, C. M. What broad emission lines tell us about how active galactic nuclei work. New Astron. Rev. 53, 140–148 (2009).
Wills, B. J. & Browne, I. W. A. Relativistic beaming and quasar emission lines. Astrophys. J. 302, 56–63 (1986).
Shen, Y. & Ho, L. C. The diversity of quasars unified by accretion and orientation. Nature 513, 210–213 (2014).
Runnoe, J. C., Brotherton, M. S., DiPompeo, M. A. & Shang, Z. The behaviour of quasar C IV emission-line properties with orientation. Mon. Not. R. Astron. Soc. 438, 3263–3274 (2014).
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).
Decarli, R., Dotti, M., Fontana, M. & Haardt, F. Are the black hole masses in narrow-line Seyfert 1 galaxies actually small? Mon. Not. R. Astron. Soc. 386, L15–L19 (2008).
Czerny, B., Du, P., Wang, J.-M. & Karas, V. A test of the formation mechanism of the broad line region in active galactic nuclei. Astrophys. J. 832, 15 (2016).
Capellupo, D. M., Netzer, H., Lira, P., Trakhtenbrot, B. & Meja-Restrepo, J. Active galactic nuclei at z ∼ 1.5—I. Spectral energy distribution and accretion discs. Mon. Not. R. Astron. Soc. 446, 3427–3446 (2015).
Capellupo, D. M., Netzer, H., Lira, P., Trakhtenbrot, B. & Meja-Restrepo, J. Active galactic nuclei at z ∼ 1.5—III. Accretion discs and black hole spin. Mon. Not. R. Astron. Soc. 460, 212–226 (2016).
Slone, O. & Netzer, H. The effects of disc winds on the spectrum and black hole growth rate of active galactic nuclei. Mon. Not. R. Astron. Soc. 426, 656–664 (2012).
Meja-Restrepo, J. E., Trakhtenbrot, B., Lira, P., Netzer, H. & Capellupo, D. M. Active galactic nuclei at z ~ 1.5—II. Black hole mass estimation by means of broad emission lines. Mon. Not. R. Astron. Soc. 460, 187–211 (2016).
Decarli, R., Labita, M., Treves, A. & Falomo, R. On the geometry of broad emission region in quasars. Mon. Not. R. Astron. Soc. 387, 1237–1247 (2008).
Nikołajuk, M., Czerny, B., Ziółkowski, J. & Gierliński, M. Consistency of the black hole mass determination in AGN from the reverberation and the X-ray excess variance method. Mon. Not. R. Astron. Soc. 370, 1534–1540 (2006).
Mortlock, D. J. et al. A luminous quasar at a redshift of z = 7.085. Nature 474, 616–619 (2011).
Wu, X.-B. et al. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30. Nature 518, 512–515 (2015).
Kaspi, S. et al. The relationship between luminosity and broad-line region size in active galactic nuclei. Astrophys. J. 629, 61–71 (2005).
Bentz, M. C., Peterson, B. M., Netzer, H., Pogge, R. W. & Vestergaard, M. The radius–luminosity relationship for active galactic nuclei: the effect of host-galaxy starlight on luminosity measurements. II. The full sample of reverberation-mapped AGNs. Astrophys. J. 697, 160–181 (2009).
Baron, D., Stern, J., Poznanski, D. & Netzer, H. Evidence that most type 1 AGN are reddened by dust in the host ISM. Astrophys. J. 832, 8 (2016).
Dunn, O. J. & Clark, V. Correlation coefficients measured on the same individuals. J. Am. Stat. Assoc. 64, 366–377 (1969).
Greene, J. E. & Ho, L. C. Estimating black hole masses in active galaxies using the Hα emission line. Astrophys. J. 630, 122–129 (2005).
Glen, A. G., Leemis, L. M. & Drew, J. H. Computing the distribution of the product of two continuous random variables. Comput. Stat. Data Anal. 44, 451–464 (2004).
Lopez, S. & Jenkins, J. S. The effects of viewing angle on the mass distribution of exoplanets. Astrophys. J. 756, 177 (2012).
Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: the MCMC hammer. Publ. Astron. Soc. Pac. 125, 306–312 (2013).
Ng, P. & Maechler, M. A fast and efficient implementation of qualitatively constrained quantile smoothing splines. Stat. Model. 7, 315–328 (2007).
Afanasiev, V. L. & Popović, L. Č. Polarization in lines—a new method for measuring black hole masses in active galaxies. Astrophys. J. 800, L35 (2015).
Support for the work of J.E.M.-R was provided by ‘CONICYT-PCHA/doctorado Nacional para extranjeros/2013-63130316’. P.L. acknowledges support from Fondecyt Project #1161184. H.N. acknowledges support from the Israel Science Foundation grant 234/13. B.T. is a Zwicky postdoctoral fellow.
The authors declare no competing financial interests.
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Mejía-Restrepo, J.E., Lira, P., Netzer, H. et al. The effect of nuclear gas distribution on the mass determination of supermassive black holes. Nat Astron 2, 63–68 (2018). https://doi.org/10.1038/s41550-017-0305-z
Nature Astronomy (2018)