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

2. Shakura, N. I. & Sunyaev, R. A. Black holes in binary systems. Observational appearance. Astron. Astrophys. 24, 337–355 (1973).

3. Collier, S. J. et al. Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. XIV. Intensive optical spectrophotometric observations of NGC 7469. Astrophys. J. 500, 162–172 (1998).

4. Fausnaugh, M. M. et al. Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548. Astrophys. J. 821, 56 (2016).

5. Edelson, R. et al. Space telescope and optical reverberation mapping project. II. Swift and HST reverberation mapping of the accretion disk of NGC 5548. Astrophys. J. 806, 129 (2015).

6. Cackett, E. M. et al. Accretion disk reverberation with Hubble Space Telescope observations of NGC 4593: evidence for diffuse continuum lags. Astrophys. J. 857, 53 (2018).

7. Blackburne, J. A., Pooley, D., Rappaport, S. & Schechter, P. L. Sizes and temperature profiles of quasar accretion disks from chromatic microlensing. Astrophys. J. 729, 34 (2011).

8. Jiménez-Vicente, J. et al. The average size and temperature profile of quasar accretion disks. Astrophys. J. 783, 47 (2014).

9. Morgan, C. W., Kochanek, C. S., Morgan, N. D. & Falco, E. E. The quasar accretion disk size—black hole mass relation. Astrophys. J. 712, 1129–1136 (2010).

10. Dexter, J. & Agol, E. Quasar accretion disks are strongly inhomogeneous. Astrophys. J. Lett. 727, L24 (2011).

11. Gardner, E. & Done, C. The origin of the UV/optical lags in NGC 5548. Mon. Not. R. Astron. Soc. 470, 3591–3605 (2017).

12. Hall, P. B., Sarrouh, G. T. & Horne, K. Non-blackbody disks can help explain inferred AGN accretion disk sizes. Astrophys. J. 854, 93 (2018).

13. Korista, K T. & Goad, M. R. The variable diffuse continuum emission of broad-line clouds. Astrophys. J. 553, 695–708 (2001).

14. McHardy, I. et al. X-ray/UV/optical variability of NGC 4593 with swift: reprocessing of X-rays by an extended reprocessor. Mon. Not. R. Astron. Soc. 480, 2881 (2018).

15. Pozo Nuñez, F., Chelouche, D., Kaspi, S. & Niv, S. Automatized photometric monitoring of active galactic nuclei with the 46 cm telescope of the wise observatory. Publ. Astron. Soc. Pac. 129, 094101 (2017).

16. Czerny, B. & Hryniewicz, K. The origin of the broad line region in active galactic nuclei. Astron. Astrophys. 525, L8 (2011).

17. Chelouche, D. The case for standard irradiated accretion disks in active galactic nuclei. Astrophys. J. 772, 9 (2013).

18. Gaskell, C. M. The case for cases B and C: intrinsic hydrogen line ratios of the broad-line region of active galactic nuclei, reddenings, and accretion disc sizes. Mon. Not. R. Astron. Soc. 467, 226–238 (2017).

19. Pancoast, A. et al. Modelling reverberation mapping data—II. Dynamical modelling of the lick AGN monitoring project 2008 data set. Mon. Not. R. Astron. Soc. 445, 3073–3091 (2014).

20. Santos-Lleó, M. et al. Monitoring of the optical and 2.5–11.7 μm spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk 279 with ISO. Astron. Astrophys. 369, 57–64 (2001).

21. Phinney, E. S. Dusty disks and the infrared emission from AGN. NATO ASI C 290, 457 (1989).

22. Sirko, E. & Goodman, J. Spectral energy distributions of marginally self-gravitating quasi-stellar object discs. Mon. Not. R. Astron. Soc. 341, 501–508 (2003).

23. Bentz, M. & Katz, S. The AGN black hole mass database. Publ. Astron. Soc. Pac. 127, 67 (2015).

24. Laor, A. & Davis, S. W. Cold accretion discs and lineless quasars. Mon. Not. R. Astron. Soc. 417, 681–688 (2011).

25. Baskin, A., Laor, A. & Stern, J. Radiation pressure confinement—II. Application to the broad-line region in active galactic nuclei. Mon. Not. R. Astron. Soc. 438, 604–619 (2014).

26. Ferland, G. J. et al. The 2017 release CLOUDY. Rev. Mex. Astron. Astr. 53, 385–438 (2017).

27. Czerny, B. et al. Failed radiatively accelerated dusty outflow model of the broad line region in active galactic nuclei. I. Analytical solution. Astrophys. J. 846, 154 (2017).

28. Bentz, M. C. et al. The low-luminosity end of the radius–luminosity relationship for active galactic nuclei. Astrophys. J. 767, 149 (2013).

29. Davis, S. W. & Laor, A. The radiative efficiency of accretion flows in individual active galactic nuclei. Astrophys. J. 728, 98 (2011).

30. Netzer, H. Revisiting the unified model of active galactic nuclei. Annu. Rev. Astron. Astrophys. 53, 365–408 (2015).

31. Bertin, E. & Arnouts, S. SExtractor: software for source extraction. Astron. Astrophys. Suppl. 117, 393–404 (1996).

32. Bertin, E. et al. The TERAPIX pipeline. In Astronomical Data Analysis Software and Systems XI (eds Bohlender, D. A., Durand, D. & Handley, T. H.) 228 (Conference Series Volume 281, Astronomical Society of the Pacific, 2002).

33. Chelouche, D., Pozo-Nuñez, F. & Zucker, S. Methods of reverberation mapping. I. Time-lag determination by measures of randomness. Astrophys. J. 844, 146 (2017).

34. Peterson, B. M. et al. On uncertainties in cross-correlation lags and the reality of wavelength-dependent continuum lags in active galactic nuclei. Publ. Astron. Soc. Pac. 110, 660–670 (1998).

35. Schlafly, E. F. & Finkbeiner, D. P. Measuring reddening with Sloan Digital Sky Survey stellar spectra and recalibrating SFD. Astrophys. J. 737, 103 (2011).

36. Choloniewski, J. The shape and variability of the nonthermal component of the optical spectra of active galaxies. Acta Astronom. 31, 293 (1981).

37. Winkler, H. et al. Variability studies of Seyfert galaxies. I—broad-band optical photometry. Mon. Not. R. Astron. Soc. 257, 659–676 (1992).

38. Pozo Nuñez, F. et al. Photometric reverberation mapping of 3C 120. Astron. Astrophys. 545, A84 (2012).

39. Sakata, Y. et al. Long-term optical continuum color variability of nearby active galactic nuclei. Astrophys. J. 711, 461–483 (2010).

40. Kinney, A. et al. Template ultraviolet to near-infrared spectra of star-forming galaxies and their application to K-corrections. Astrophys. J. 467, 38 (1996).

41. Pogge, R. & Martini, P. Hubble Space Telescope imaging of the circumnuclear environments of the CfA Seyfert galaxies: nuclear spirals and fueling. Astrophys. J. 569, 624–640 (2002).

42. Peterson, B. M. Reverberation mapping of active galactic nuclei. Publ. Astron. Soc. Pac. 105, 247–268 (1993).

43. Alexander, T. Improved AGN light curve analysis with the z-transformed discrete correlation function. Preprint at https://arxiv.org/abs/1302.1508 (2013).

44. Rybicki, G. B. & Press, W. H. Interpolation, realization, and reconstruction of noisy, irregularly sampled data. Astrophys. J. 398, 169–176 (1992).

45. Zu, Y., Kochanek, C. S. & Peterson, B. M. An alternative approach to measuring reverberation lags in active galactic nuclei. Astrophys. J. 735, 80 (2011).

46. Li, Y.-R., Wang, J.-M. & Bai, J.-M. A non-parametric approach to constrain the transfer function in reverberation mapping. Astrophys. J. 831, 206 (2016).

47. Chelouche, D. & Zucker, S. Quasar cartography: from black hole to broad-line region scales. Astrophys. J. 769, 124 (2013).

48. Pijpers, F. P. & Wanders, I. Reverberation mapping of active galactic nuclei: the SOLA method for time-series inversion. Mon. Not. R. Astron. Soc. 271, 183–196 (1994).

49. Welsh, W. F. On the reliability of cross-correlation function lag determinations in active galactic nuclei. Publ. Astron. Soc. Pac. 111, 1347–1366 (1999).

50. Scott, J. E. et al. Variable intrinsic absorption in Mrk 279. Astrophys. J. 694, 438–448 (2009).

51. Stevans, M. L., Shull, J. M., Danforth, C. W. & Tilton, E. M. HST-COS observations of AGNs. II. Extended survey of ultraviolet composite spectra from 159 active galactic nuclei. Astrophys. J. 794, 75 (2014).

52. Mehdipour, M. et al. Multi-wavelength campaign on NGC 7469. III. Spectral energy distribution and the AGN wind photoionisation modelling, plus detection of diffuse X-rays from the starburst with Chandra HETGS. Astron. Astrophys. 615, A72 (2018).

53. Warner, C., Hamann, F. & Dietrich, M. A relation between supermassive black hole mass and quasar metallicity?. Astrophys. J. 596, 72–84 (2003).

54. Dietrich, M. et al. Continuum and emission-line strength relations for a large active galactic nuclei sample. Astrophys. J. 581, 912–912 (2002).

55. Maoz, D. et al. High-rate spectroscopic active galactic nucleus monitoring at the Wise Observatory. I—Markarian 279. Astrophys. J. 351, 75–82 (1990).

56. Stern, J. & Laor, A. Type 1 AGN at low z. I. Emission properties. J. Phys. Conf. Ser. 423, 600–631 (2012).