The majority of the accreting supermassive black holes in the Universe are obscured by large columns of gas and dust1,2,3. The location and evolution of this obscuring material have been the subject of intense research in the past decades4,5, and are still debated. A decrease in the covering factor of the circumnuclear material with increasing accretion rates has been found by studies across the electromagnetic spectrum1,6,7,8. The origin of this trend may be driven by the increase in the inner radius of the obscuring material with incident luminosity, which arises from the sublimation of dust9; by the gravitational potential of the black hole10; by radiative feedback11,12,13,14; or by the interplay between outflows and inflows15. However, the lack of a large, unbiased and complete sample of accreting black holes, with reliable information on gas column density, luminosity and mass, has left the main physical mechanism that regulates obscuration unclear. Here we report a systematic multi-wavelength survey of hard-X-ray-selected black holes that reveals that radiative feedback on dusty gas is the main physical mechanism that regulates the distribution of the circumnuclear material. Our results imply that the bulk of the obscuring dust and gas is located within a few to tens of parsecs of the accreting supermassive black hole (within the sphere of influence of the black hole), and that it can be swept away even at low radiative output rates. The main physical driver of the differences between obscured and unobscured accreting black holes is therefore their mass-normalized accretion rate.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Burlon, D. et al. Three-year Swift-BAT survey of active galactic nuclei: reconciling theory and observations? Astrophys. J. 728, 58 (2011)
Ueda, Y., Akiyama, M., Hasinger, G., Miyaji, T. & Watson, M. G. Toward the standard population synthesis model of the X-ray background: evolution of X-Ray luminosity and absorption functions of active galactic nuclei including Compton-thick populations. Astrophys. J. 786, 104 (2014)
Ricci, C. et al. Compton-thick accretion in the local Universe. Astrophys. J. 815, L13 (2015)
Elitzur, M. & Shlosman, I. The AGN-obscuring torus: the end of the “doughnut” paradigm? Astrophys. J. 648, L101–L104 (2006)
Merloni, A. et al. The incidence of obscuration in active galactic nuclei. Mon. Not. R. Astron. Soc. 437, 3550–3567 (2014)
Ueda, Y., Akiyama, M., Ohta, K. & Miyaji, T. Cosmological evolution of the hard X-ray active galactic nucleus luminosity function and the origin of the hard X-ray background. Astrophys. J. 598, 886–908 (2003)
Maiolino, R. et al. Dust covering factor, silicate emission, and star formation in luminous QSOs. Astron. Astrophys. 468, 979–992 (2007)
Treister, E., Krolik, J. H. & Dullemond, C. Measuring the fraction of obscured quasars by the infrared luminosity of unobscured quasars. Astrophys. J. 679, 140–148 (2008)
Lawrence, A. The relative frequency of broad-lined and narrow-lined active galactic nuclei—implications for unified schemes. Mon. Not. R. Astron. Soc. 252, 586–592 (1991)
Lamastra, A., Perola, G. C. & Matt, G. A model for the X-ray absorption in Compton-thin AGN. Astron. Astrophys. 449, 551–558 (2006)
Fabian, A. C., Celotti, A. & Erlund, M. C. Radiative pressure feedback by a quasar in a galactic bulge. Mon. Not. R. Astron. Soc. 373, L16–L20 (2006)
Menci, N., Fiore, F., Puccetti, S. & Cavaliere, A. The blast wave model for AGN feedback: effects on AGN obscuration. Astrophys. J. 686, 219–229 (2008)
Fabian, A. C., Vasudevan, R. V. & Gandhi, P. The effect of radiation pressure on dusty absorbing gas around active galactic nuclei. Mon. Not. R. Astron. Soc. 385, L43–L47 (2008)
Fabian, A. C., Vasudevan, R. V., Mushotzky, R. F., Winter, L. M. & Reynolds, C. S. Radiation pressure and absorption in AGN: results from a complete unbiased sample from Swift. Mon. Not. R. Astron. Soc. 394, L89–L92 (2009)
Wada, K. Obscuring fraction of active galactic nuclei: implications from radiation-driven fountain models. Astrophys. J. 812, 82 (2015)
Gehrels, N. et al. The Swift gamma-ray burst mission. Astrophys. J. 611, 1005–1020 (2004)
Barthelmy, S. D. et al. The Burst Alert Telescope (BAT) on the SWIFT Midex mission. Space Sci. Rev. 120, 143–164 (2005)
Ricci, C. et al. BAT AGN Spectroscopic Survey — V. X-ray properties of the Swift/BAT 70-month AGN catalog. Astrophys. J. Suppl. Ser. (in the press)
Koss, M. J. et al. BAT AGN spectroscopic survey I: spectral measurements, derived quantities, and AGN demographics. Preprint at https://arxiv.org/abs/1707.08123 (2017)
Cameron, E. On the estimation of confidence intervals for binomial population proportions in astronomy: the simplicity and superiority of the Bayesian approach. Publ. Astron. Soc. Aust. 28, 128–139 (2011)
Antonucci, R. Unified models for active galactic nuclei and quasars. Annu. Rev. Astron. Astrophys. 31, 473–521 (1993)
Hopkins, P. F. et al. A unified, merger-driven model of the origin of starbursts, quasars, the cosmic X-ray background, supermassive black holes, and galaxy spheroids. Astrophys. J. Suppl. Ser. 163, 1–49 (2006)
Satyapal, S. et al. Galaxy pairs in the Sloan Digital Sky Survey— IX. Merger-induced AGN activity as traced by the Wide-field Infrared Survey Explorer. Mon. Not. R. Astron. Soc. 441, 1297–1304 (2014)
Kocevski, D. D. et al. Are Compton-thick AGNs the missing link between mergers and black hole growth? Astrophys. J. 814, 104 (2015)
Ricci, C. et al. Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured. Mon. Not. R. Astron. Soc. 468, 1273–1299 (2017)
Jaffe, W. et al. The central dusty torus in the active nucleus of NGC 1068. Nature 429, 47–49 (2004)
Hönig, S. F. et al. Dust in the polar region as a major contributor to the infrared emission of active galactic nuclei. Astrophys. J. 771, 87 (2013)
Asmus, D., Hönig, S. F. & Gandhi, P. The subarcsecond mid-infrared view of local active galactic nuclei. III. Polar dust emission. Astrophys. J. 822, 109 (2016)
Fabian, A. C. Observational evidence of active galactic nuclei feedback. Annu. Rev. Astron. Astrophys. 50, 455–489 (2012)
Kormendy, J. & Ho, L. C. Coevolution (or not) of supermassive black holes and host galaxies. Annu. Rev. Astron. Astrophys. 51, 511–653 (2013)
Krimm, H. A. et al. The Swift/BAT hard X-ray transient monitor. Astrophys. J. Suppl. Ser. 209, 14 (2013)
Baumgartner, W. H. et al. The 70 month Swift-BAT all-sky hard X-ray survey. Astrophys. J. Suppl. Ser. 207, 19 (2013)
Massaro, E. et al. The 5th edition of the Roma-BZCAT. A short presentation. Astrophys. Space Sci. 357, 75 (2015)
Koss, M. J. et al. A new population of Compton-thick AGNs identified using the spectral curvature above 10 keV. Astrophys. J. 825, 85 (2016)
Akylas, A. et al. Compton-thick AGN in the 70-month Swift-BAT all-sky hard x-ray survey: a Bayesian approach. Astron. Astrophys. 594, A73 (2016)
Lamperti, I. et al. BAT AGN spectroscopic survey—IV: near-infrared coronal lines, hidden broad lines, and correlation with hard X-ray emission. Mon. Not. R. Astron. Soc. 467, 540–572 (2017)
Berney, S. et al. BAT AGN spectroscopic survey—II. X-ray emission and high-ionization optical emission lines. Mon. Not. R. Astron. Soc. 454, 3622–3634 (2015)
Ueda, Y. et al. [O iii] λ5007 and X-ray properties of a complete sample of hard X-ray selected AGNs in the local Universe. Astrophys. J. 815, 1 (2015)
Oh, K. et al. BAT AGN spectroscopic survey—III. An observed link between AGN Eddington ratio and narrow-emission-line ratios. Mon. Not. R. Astron. Soc. 464, 1466–1473 (2017)
Trakhtenbrot, B. et al. The Swift/BAT AGN spectroscopic survey (BASS)—VI. The ΓX–L/LEdd relation. Mon. Not. R. Astron. Soc. 470, 800–814 (2017)
Magdziarz, P. & Zdziarski, A. A. Angle-dependent Compton reflection of X-rays and gamma-rays. Mon. Not. R. Astron. Soc. 273, 837–848 (1995)
Nandra, K. & Pounds, K. A. GINGA observations of the X-Ray spectra of Seyfert galaxies. Mon. Not. R. Astron. Soc. 268, 405–429 (1994)
Shu, X. W., Yaqoob, T. & Wang, J. X. The cores of the Fe Kα lines in active galactic nuclei: an extended Chandra high energy grating sample. Astrophys. J. Suppl. Ser. 187, 581–606 (2010)
Ricci, C. et al. The narrow Fe Kα line and the molecular torus in active galactic nuclei: an IR/X-ray view. Astron. Astrophys. 567, A142 (2014)
Ueda, Y. et al. Suzaku observations of active galactic nuclei detected in the Swift BAT survey: discovery of a “new type” of buried supermassive black holes. Astrophys. J. 664, L79–L82 (2007)
Kawamuro, T ., Ueda, Y ., Tazaki, F ., Ricci, C & Terashima, Y. Suzaku observations of moderately obscured (Compton-thin) active galactic nuclei selected by Swift/BAT hard X-ray survey. Astrophys. J. Suppl. Ser. 225, 14 (2016)
Brightman, M. & Nandra, K. An XMM-Newton spectral survey of 12 μm selected galaxies—I. X-ray data. Mon. Not. R. Astron. Soc. 413, 1206–1235 (2011)
Bentz, M. C. & Katz, S. The AGN black hole mass database. Publ. Astron. Soc. Pac. 127, 67 (2015)
Trakhtenbrot, B. & Netzer, H. Black hole growth to z = 2—I. Improved virial methods for measuring MBH and L/LEdd . Mon. Not. R. Astron. Soc. 427, 3081–3102 (2012)
Oh, K. et al. A new catalog of type 1 AGNs and its implications on the AGN unified model. Astrophys. J. Suppl. Ser. 219, 1 (2015)
Greene, J. E. & Ho, L. C. Estimating black hole masses in active galaxies using the Hα emission line. Astrophys. J. 630, 122–129 (2005)
Shen, Y. The mass of quasars. Bull. Astron. Soc. India 41, 61–115 (2013)
Peterson, B. M. Measuring the masses of supermassive black holes. Space Sci. Rev. 183, 253–275 (2014)
Gebhardt, K. et al. A relationship between nuclear black hole mass and galaxy velocity dispersion. Astrophys. J. 539, L13–L16 (2000)
Vasudevan, R. V. & Fabian, A. C. Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM-Newton: spectral energy distributions for the reverberation mapped sample. Mon. Not. R. Astron. Soc. 392, 1124–1140 (2009)
Hönig, S. F. & Beckert, T. Active galactic nuclei dust tori at low and high luminosities. Mon. Not. R. Astron. Soc. 380, 1172–1176 (2007)
Ferland, G. J. Hazy, A Brief Introduction to Cloudy 84 (1993)
Liu, Y. & Zhang, S. N. Dusty torus formation by anisotropic radiative pressure feedback of active galactic nuclei. Astrophys. J. 728, L44 (2011)
Raimundo, S. I. et al. Radiation pressure, absorption and AGN feedback in the Chandra deep fields. Mon. Not. R. Astron. Soc. 408, 1714–1720 (2010)
Vasudevan, R. V. et al. Three active galactic nuclei close to the effective Eddington limit for dusty gas. Mon. Not. R. Astron. Soc. 431, 3127–3138 (2013)
Lawrence, A. & Elvis, M. Obscuration and the various kinds of Seyfert galaxies. Astrophys. J. 256, 410–426 (1982)
Simpson, C. The luminosity dependence of the type 1 active galactic nucleus fraction. Mon. Not. R. Astron. Soc. 360, 565–572 (2005)
La Franca, F. et al. The HELLAS2XMM survey. VII. The hard X-ray luminosity function of AGNs up to z = 4: more absorbed AGNs at low luminosities and high redshifts. Astrophys. J. 635, 864–879 (2005)
Sazonov, S., Revnivtsev, M., Krivonos, R., Churazov, E. & Sunyaev, R. Hard X-ray luminosity function and absorption distribution of nearby AGN: INTEGRAL all-sky survey. Astron. Astrophys. 462, 57–66 (2007)
Hasinger, G. Absorption properties and evolution of active galactic nuclei. Astron. Astrophys. 490, 905–922 (2008)
Della Ceca, R. et al. The cosmological properties of AGN in the XMM-Newton hard bright survey. Astron. Astrophys. 487, 119–130 (2008)
Beckmann, V. et al. The second INTEGRAL AGN catalogue. Astron. Astrophys. 505, 417–439 (2009)
Ueda, Y. et al. Revisit of local X-ray luminosity function of active galactic nuclei with the MAXI extragalactic survey. Publ. Astron. Soc. Jpn 63, S937–S945 (2011)
Brightman, M. & Nandra, K. An XMM-Newton spectral survey of 12 μm selected galaxies—II. Implications for AGN selection and unification. Mon. Not. R. Astron. Soc. 414, 3084–3104 (2011)
Buchner, J. et al. Obscuration-dependent evolution of active galactic nuclei. Astrophys. J. 802, 89 (2015)
Aird, J. et al. The evolution of the X-ray luminosity functions of unabsorbed and absorbed AGNs out to z ∼ 5. Mon. Not. R. Astron. Soc. 451, 1892–1927 (2015)
Georgakakis, A. et al. X-ray constraints on the fraction of obscured active galactic nuclei at high accretion luminosities. Mon. Not. R. Astron. Soc. 469, 3232–3251 (2017)
Ricci, C. et al. Luminosity-dependent unification of active galactic nuclei and the X-ray Baldwin effect. Astron. Astrophys. 553, A29 (2013)
Iwasawa, K. & Taniguchi, Y. The X-ray Baldwin effect. Astrophys. J. 413, L15–L18 (1993)
Bianchi, S., Guainazzi, M., Matt, G. & Fonseca Bonilla, N. On the Iwasawa-Taniguchi effect of radio-quiet AGN. Astron. Astrophys. 467, L19–L22 (2007)
Ricci, C. et al. Iron Kα emission in type-I and type-II active galactic nuclei. Mon. Not. R. Astron. Soc. 441, 3622–3633 (2014)
Tueller, J. et al. Swift BAT survey of AGNs. Astrophys. J. 681, 113–127 (2008)
Gandhi, P. et al. Resolving the mid-infrared cores of local Seyferts. Astron. Astrophys. 502, 457–472 (2009)
Assef, R. J. et al. Mid-infrared selection of active galactic nuclei with the Wide-field Infrared Survey Explorer. II. Properties of WISE-selected active galactic nuclei in the ND-WFS Boötes Field. Astrophys. J. 772, 26 (2013)
Lusso, E. et al. The obscured fraction of active galactic nuclei in the XMM-COSMOS survey: a spectral energy distribution perspective. Astrophys. J. 777, 86 (2013)
Toba, Y. et al. Luminosity and redshift dependence of the covering factor of active galactic nuclei viewed with WISE and Sloan Digital Sky Survey. Astrophys. J. 788, 45 (2014)
Lacy, M. et al. The Spitzer mid-infrared AGN Survey. II. The demographics and cosmic evolution of the AGN population. Astrophys. J. 802, 102 (2015)
Stalevski, M. et al. The dust covering factor in active galactic nuclei. Mon. Not. R. Astron. Soc. 458, 2288–2302 (2016)
Mateos, S. et al. X-ray absorption, nuclear infrared emission, and dust covering factors of AGNs: testing unification schemes. Astrophys. J. 819, 166 (2016)
Ichikawa, K. et al. The complete infrared view of active galactic nuclei from the 70 month Swift/BAT catalog. Astrophys. J. 835, 74 (2017)
Netzer, H. et al. Star formation black hole growth and dusty tori in the most luminous AGNs at z = 2–3.5. Astrophys. J. 819, 123 (2016)
Hönig, S. F., Beckert, T., Ohnaka, K. & Weigelt, G. Radiative transfer modeling of three-dimensional clumpy AGN tori and its application to NGC 1068. Astron. Astrophys. 452, 459–471 (2006)
Nenkova, M., Sirocky, M. M., Nikutta, R., Ivezic´, Z. & Elitzur, M. AGN dusty tori. II. Observational implications of clumpiness. Astrophys. J. 685, 160–180 (2008)
Nenkova, M., Sirocky, M. M., Ivezic´, Z. & Elitzur, M. AGN dusty tori. I. Handling of clumpy media. Astrophys. J. 685, 147–159 (2008)
Schartmann, M. et al. Three-dimensional radiative transfer models of clumpy tori in Seyfert galaxies. Astron. Astrophys. 482, 67–80 (2008)
Hönig, S. F. & Kishimoto, M. The dusty heart of nearby active galaxies. II. From clumpy torus models to physical properties of dust around AGN. Astron. Astrophys. 523, A27 (2010)
Hönig, S. F. et al. The dusty heart of nearby active galaxies. I. High-spatial resolution mid-IR spectro-photometry of Seyfert galaxies. Astron. Astrophys. 515, A23 (2010)
Stalevski, M., Fritz, J., Baes, M., Nakos, T. & Popovic´, L. Cˇ. 3D radiative transfer modelling of the dusty tori around active galactic nuclei as a clumpy two-phase medium. Mon. Not. R. Astron. Soc. 420, 2756–2772 (2012)
Siebenmorgen, R., Heymann, F. & Efstathiou, A. Self-consistent two-phase AGN torus models. SED library for observers. Astron. Astrophys. 583, A120 (2015)
Mor, R., Netzer, H. & Elitzur, M. Dusty structure around type-I active galactic nuclei: clumpy torus narrow-line region and near-nucleus hot dust. Astrophys. J. 705, 298–313 (2009)
Alonso-Herrero, A. et al. Torus and active galactic nucleus properties of nearby Seyfert galaxies: results from fitting infrared spectral energy distributions and spectroscopy. Astrophys. J. 736, 82 (2011)
Ramos Almeida, C. et al. Testing the unification model for active galactic nuclei in the infrared: are the obscuring tori of type 1 and 2 Seyferts different? Astrophys. J. 731, 92 (2011)
Elitzur, M. On the unification of active galactic nuclei. Astrophys. J. 747, L33 (2012)
Suganuma, M. et al. Reverberation measurements of the inner radius of the dust torus in nearby Seyfert 1 galaxies. Astrophys. J. 639, 46–63 (2006)
Kishimoto, M., Hönig, S. F., Beckert, T. & Weigelt, G. The innermost region of AGN tori: implications from the HST/NICMOS type 1 point sources and near-IR reverberation. Astron. Astrophys. 476, 713–721 (2007)
Kishimoto, M. et al. Mapping the radial structure of AGN tori. Astron. Astrophys. 536, A78 (2011)
Davies, R. I. et al. Insights on the dusty torus and neutral torus from optical and X-ray obscuration in a complete volume limited hard X-ray AGN sample. Astrophys. J. 806, 127 (2015)
Sazonov, S., Churazov, E. & Krivonos, R. Does the obscured AGN fraction really depend on luminosity? Mon. Not. R. Astron. Soc. 454, 1202–1220 (2015)
Netzer, H. Revisiting the unified model of active galactic nuclei. Annu. Rev. Astron. Astrophys. 53, 365–408 (2015)
Brandt, W. N. & Alexander, D. M. Cosmic X-ray surveys of distant active galaxies. The demographics, physics, and ecology of growing supermassive black holes. Astron. Astrophys. Rev. 23, 1 (2015)
Kawamuro, T., Ueda, Y., Tazaki, F., Terashima, Y. & Mushotzky, R. Study of Swift/Bat selected low-luminosity active galactic nuclei observed with Suzaku. Astrophys. J. 831, 37 (2016)
Winter, L. M., Mushotzky, R. F., Reynolds, C. S. & Tueller, J. X-ray spectral properties of the BAT AGN sample. Astrophys. J. 690, 1322–1349 (2009)
Lusso, E. et al. Bolometric luminosities and Eddington ratios of X-ray selected active galactic nuclei in the XMM-COSMOS survey. Mon. Not. R. Astron. Soc. 425, 623–640 (2012)
Buchner, J. & Bauer, F. E. Galaxy gas as obscurer—II. Separating the galaxy-scale and nuclear obscurers of active galactic nuclei. Mon. Not. R. Astron. Soc. 465, 4348–4362 (2017)
Koss, M., Mushotzky, R., Veilleux, S. & Winter, L. Merging and clustering of the Swift BAT AGN sample. Astrophys. J. 716, L125–L130 (2010)
Marconi, A. & Hunt, L. K. The relation between black hole mass, bulge mass, and near-infrared luminosity. Astrophys. J. 589, L21–L24 (2003)
Vasudevan, R. V. & Fabian, A. C. Piecing together the X-ray background: bolometric corrections for active galactic nuclei. Mon. Not. R. Astron. Soc. 381, 1235–1251 (2007)
Peebles, P. J. E. Star distribution near a collapsed object. Astrophys. J. 178, 371–376 (1972)
Brightman, M. et al. Compton thick active galactic nuclei in Chandra surveys. Mon. Not. R. Astron. Soc. 443, 1999–2017 (2014)
Tacconi, L. J. et al. High molecular gas fractions in normal massive star-forming galaxies in the young Universe. Nature 463, 781–784 (2010)
Genel, S., Genzel, R., Bouché, N., Naab, T. & Sternberg, A. The halo merger rate in the millennium simulation and implications for observed galaxy merger fractions. Astrophys. J. 701, 2002–2018 (2009)
Rodriguez-Gomez, V. et al. The merger rate of galaxies in the Illustris simulation: a comparison with observations and semi-empirical models. Mon. Not. R. Astron. Soc. 449, 49–64 (2015)
Marshall, H. L., Tananbaum, H., Avni, Y. & Zamorani, G. Analysis of complete quasar samples to obtain parameters of luminosity and evolution functions. Astrophys. J. 269, 35–41 (1983)
This work is dedicated to the memory of our friend and collaborator Neil Gehrels. We acknowledge the work done by the Swift/BAT team to make this project possible. We thank M. Kishimoto, C.-S. Chang, D. Asmus, M. Stalevski, P. Gandhi and G. Privon for discussions. We thank N. Secrest for providing us with the stellar masses of the Swift/BAT sample. This paper is part of the Swift/BAT AGN Spectroscopic Survey (BASS, http://www.bass-survey.com). This work is sponsored by the Chinese Academy of Sciences (CAS), through a grant to the CAS South America Center for Astronomy (CASSACA) in Santiago, Chile. We acknowledge financial support from FONDECYT 1141218 (C.R., F.E.B.), FONDECYT 1160999 (E.T.), Basal-CATA PFB–06/2007 (C.R., E.T., F.E.B.), the China-CONICYT fund (C.R.), the Swiss National Science Foundation (grant PP00P2 138979 and PP00P2 166159, K.S.), the Swiss National Science Foundation (SNSF) through the Ambizione fellowship grant PZ00P2 154799/1 (M.J.K.), the NASA ADAP award NNH16CT03C (M.J.K.), the Chinese Academy of Science grant no. XDB09030102 (L.C.H.), the National Natural Science Foundation of China grant no. 11473002 (L.C.H.), the Ministry of Science and Technology of China grant no. 2016YFA0400702 (L.C.H.), the ERC Advanced Grant Feedback 340442 (A.C.F.), and the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS (F.E.B.). Part of this work was carried out while C.R. was Fellow of the Japan Society for the Promotion of Science (JSPS) at Kyoto University. This work was partly supported by the Grant-in-Aid for Scientific Research 17K05384 (Y.U.) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT). We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).
The authors declare no competing financial interests.
Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Extended data figures and tables
a–c, Histograms of λEdd for unobscured (NH < 1022 cm−2; a), obscured Compton-thin (1022 cm−2 ≤ NH < 1024 cm−2; b) and Compton-thick (NH ≥ 1024 cm−2; c) AGN. The vertical red dashed lines show the median values for the different subsets of sources.
a, b, Scatter plots of λEdd versus the 2–10-keV intrinsic luminosity (L2–10; a) and the black hole mass (MBH; b) for unobscured (NH ≤ 1022 cm−2; black open diamonds), obscured (1022 cm−2 ≤ NH < 1024 cm−2; red filled circles) and Compton-thick (NH ≥ 1024 cm−2; blue filled squares) AGN. The black dashed lines represent values for constant mass (a) and luminosity (b).
Fraction of obscured Compton-thin sources versus the intrinsic 14–150-keV luminosities for the non-blazar AGN of the Swift/BAT 70-month catalogue. The fraction of obscured sources is normalized in the NH = 1020–1024 cm−2 range. The filled area represents the 16th and 84th quantiles of a binomial distribution20.
Extended Data Figure 4 Fraction of obscured sources versus λEdd for two ranges of luminosity and black hole mass.
a, b, Fraction of obscured Compton-thin sources versus Eddington ratio for two bins of the 14–150-keV intrinsic luminosity (a) and of the black hole mass (b). The dashed vertical lines represent the effective Eddington limit for dusty gas with NH = 1022 cm−2 () and NH = 1023 cm−2 (). The plots are normalized to unity in the interval 20≤ log[NH (cm−2)] < 24, and the shaded areas represent the 16th and 84th quantiles of a binomial distribution20. The same trend found for the whole sample is obtained when looking at different bins of L14–150 and MBH, confirming that the Eddington ratio is the main parameter driving obscuration.
Extended Data Figure 5 Relation between the fraction of obscured AGN and the Eddington ratio assuming different bolometric corrections.
a, b, The bolometric corrections used are dependent on the bolometric luminosity (a; blue111 and red108 lines) and on the Eddington ratio (b; blue112 and red108 lines). The shaded areas represent the 16th and 84th quantiles of a binomial distribution20. The figure shows that our results are mostly independent on the choice of the bolometric correction.
Extended Data Figure 6 Median value of the column density versus Eddington ratio for AGN with 20 ≤ log[NH (cm−2)] ≤ 24.
The plot highlights the sharp transition at log(λEdd) ≈ −1.5 between AGN being typically obscured to unobscured. The filled area shows the median absolute deviation. The dashed vertical lines represent the effective Eddington limit for a dusty gas with NH = 1022 cm−2 () and NH = 1023 cm−2 () for standard dust grain composition of the interstellar medium, showing that radiation pressure regulates the median column density of AGN.
Extended Data Figure 7 Median value of the column density versus Eddington ratio for different luminosity and black hole mass ranges.
a, b, Same as Extended Data Fig. 6 but for two different ranges of the intrinsic 14–150-keV luminosity (a; in erg s−1) and black hole mass (b; in M⊙). The filled areas represent the median absolute deviations. The dashed vertical lines represent the effective Eddington limit for dusty gas with NH = 1022 cm−2 () and NH = 1023 cm−2 () for standard dust grain composition of the interstellar medium.
About this article
Cite this article
Ricci, C., Trakhtenbrot, B., Koss, M. et al. The close environments of accreting massive black holes are shaped by radiative feedback. Nature 549, 488–491 (2017). https://doi.org/10.1038/nature23906
The Astrophysical Journal (2020)
The Astrophysical Journal (2020)
Astronomy & Astrophysics (2020)
The Astrophysical Journal (2020)
The Astrophysical Journal (2020)