The power of relativistic jets is larger than the luminosity of their accretion disks


Theoretical models for the production of relativistic jets from active galactic nuclei predict that jet power arises from the spin and mass of the central supermassive black hole, as well as from the magnetic field near the event horizon1. The physical mechanism underlying the contribution from the magnetic field is the torque exerted on the rotating black hole by the field amplified by the accreting material. If the squared magnetic field is proportional to the accretion rate, then there will be a correlation between jet power and accretion luminosity. There is evidence for such a correlation2,3,4,5,6,7,8, but inadequate knowledge of the accretion luminosity of the limited and inhomogeneous samples used prevented a firm conclusion. Here we report an analysis of archival observations of a sample of blazars (quasars whose jets point towards Earth) that overcomes previous limitations. We find a clear correlation between jet power, as measured through the γ-ray luminosity, and accretion luminosity, as measured by the broad emission lines, with the jet power dominating the disk luminosity, in agreement with numerical simulations9. This implies that the magnetic field threading the black hole horizon reaches the maximum value sustainable by the accreting matter10.

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Figure 1: Radiative jet power versus disk luminosity.
Figure 2: Jet power versus accretion power.


  1. 1

    Blandford, R. D. & Znajek, R. L. Electromagnetic extraction of energy from Kerr black holes. Mon. Not. R. Astron. Soc. 179, 433–456 (1977)

  2. 2

    Rawlings, S. & Saunders, R. Evidence for a common central-engine mechanism in all extragalactic radio sources. Nature 349, 138–140 (1991)

  3. 3

    Celotti, A. & Fabian, A. C. The Kinetic power and luminosity of parsec-scale radio jets – an argument for heavy jets. Mon. Not. R. Astron. Soc. 264, 228–236 (1993)

  4. 4

    Celotti, A., Padovani, P. & Ghisellini, G. Jets and accretion processes in active galactic nuclei: further clues. Mon. Not. R. Astron. Soc. 286, 415–424 (1997)

  5. 5

    Maraschi, L. & Tavecchio, F. The jet–disk connection and blazar unification. Astrophys. J. 593, 667–675 (2003)

  6. 6

    Punsly, B. & Tingay, S. J. PKS 1018–42: a powerful, kinetically dominated quasar. Astrophys. J. 640, L21–L24 (2006)

  7. 7

    Celotti, A. & Ghisellini, G. The power of blazar jets. Mon. Not. R. Astron. Soc. 385, 283–300 (2008)

  8. 8

    Ghisellini, G. et al. General physical properties of bright Fermi blazars. Mon. Not. R. Astron. Soc. 402, 497–518 (2010)

  9. 9

    Tchekhovskoy, A., Narayan, R. & McKinney, J. C. Efficient generation of jets from magnetically arrested accretion on a rapidly spinning black hole. Mon. Not. R. Astron. Soc. 418, L79–L83 (2011)

  10. 10

    Zamaninasab, M., Clausen–Brown, E., Savolainen, T. & Tchekhoskoy, A. Dynamically important magnetic fields near accreting supermassive black holes. Nature 510, 126–128 (2014)

  11. 11

    Thorne, K. Disk–accretion onto a black hole. II. Evolution of the hole. Astrophys. J. 191, 507–519 (1974)

  12. 12

    Shaw, M. S., Romani, R. W. & Cotter, G. et al. Spectroscopy of broad–line blazars from 1LAC. Astrophys. J. 748, 49 (2012)

  13. 13

    Shaw, M. S., Romani, R. W. & Cotter, G. et al. Spectroscopy of the largest ever γ-ray-selected BL Lac sample. Astrophys. J. 764, 135 (2013)

  14. 14

    Francis, J. et al. A high signal–to–noise ratio composite quasar spectrum. Astrophys. J. 373, 465–470 (1991)

  15. 15

    Vanden Berk, D. E., Richards, G. T. & Bauer, A. Composite quasar spectra from the Sloan Digital Sky Survey. Astron. J. 122, 549–564 (2001)

  16. 16

    Calderone, G., Ghisellini, G., Colpi, M. & Dotti, M. Black hole mass estimate for a sample of radio-loud narrow-line Seyfert 1 galaxies. Mon. Not. R. Astron. Soc. 431, 210–239 (2013)

  17. 17

    Ghisellini, G. & Tavecchio, F. Canonical high–power blazars. Mon. Not. R. Astron. Soc. 397, 985–1002 (2009)

  18. 18

    Ghisellini, G. & Tavecchio, F. Compton rockets and the minimum power of relativistic jets. Mon. Not. R. Astron. Soc. 409, L79–L83 (2010)

  19. 19

    Nolan, P. L., Abdo, A. A. & Ackermann, M. et al. Fermi Large Area Telescope second source catalog. Astrophys. J. Suppl. Ser. 199, 31 (2012)

  20. 20

    Ghirlanda, G., Ghisellini, G., Tavecchio, F., Foschini, L. & Bonnoli, G. The radio–γ-ray connection in Fermi blazars. Mon. Not. R. Astron. Soc. 413, 852–862 (2011)

  21. 21

    Nemmen, R. S. et al. A universal scaling for the energetics of relativistic jets from black hole systems. Science 338, 1445–1448 (2012)

  22. 22

    Tchekhovskoy, A., Metzger, B. D., Giannios, D. & Kelley, L. Z. Swift J1644+57 gone MAD: the case for dynamically important magnetic flux threading the black hole in a jetted tidal disruption event. Mon. Not. R. Astron. Soc. 437, 2744–2760 (2014)

  23. 23

    Peterson, B. M. & Wandel, A. Evidence for supermassive black holes in active galactic nuclei from emission-line reverberation. Astrophys. J. 540, L13–L16 (2000)

  24. 24

    McLure, R. J. & Dunlop, J. S. The cosmological evolution of quasar black hole masses. Mon. Not. R. Astron. Soc. 352, 1390–1404 (2004)

  25. 25

    Vestergaard, M. & Peterson, B. M. Determining central black hole masses in distant active galaxies and quasars. II. Improved optical and UV scaling relationships. Astrophys. J. 641, 689–709 (2006)

  26. 26

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

  27. 27

    Livio, M., Ogilvie, G. I. & Pringle, J. E. Extracting energy from black holes: the relative importance of the Blandford-Znajek mechanism. Astrophys. J. 512, 100–104 (1999)

  28. 28

    Meier, D. L. Grand unification of AGN and the accretion and spin paradigms. New Astron. Rev. 46, 247–255 (2002)

  29. 29

    Tchekhovskoy, A., McKinney, J. C. & Narayan, R. General relativistic modeling of magnetized jets from accreting black holes. J. Phys. Conf. Ser. 372, 012040 (2012)

  30. 30

    Sikora, M., Stawarz, L. & Lasota, J.-P. Radio loudness of active galactic nuclei: observational facts and theoretical implications. Astrophys. J. 658, 815–828 (2007)

  31. 31

    Abdo, A. A. et al. The first catalog of active galactic nuclei detected by the Fermi Large Area Telescope. Astrophys. J. 715, 429–457 (2010)

  32. 32

    Ackermann, M. et al. The second catalog of active galactic nuclei detected by the Fermi Large Area Telescope. Astrophys. J. 743, 171 (2011)

  33. 33

    Shen, Y. et al. A catalog of quasar properties from Sloan Digital Sky Survey data release 7. Astrophys. J. Supp. Ser. 194, 45 (2011)

  34. 34

    Ghisellini, G. Extragalactic relativistic jets. AIP Conf. Proc. 1381, 180–198 (2011)

  35. 35

    Sbarrato, T. et al. Blazar candidates beyond redshift 4 observed with GROND. Mon. Not. R. Astron. Soc. 433, 2182–2193 (2013)

  36. 36

    Fossati, G., Maraschi, L., Celotti, A., Comastri, A. & Ghisellini, G. A unifying view of the spectral energy distributions of blazars. Mon. Not. R. Astron. Soc. 299, 433–448 (1998)

  37. 37

    Donato, D., Ghisellini, G., Tagliaferri, G. & Fossati, G. Hard X-ray properties of blazars. Astron. Astrophys. 375, 739–751 (2001)

  38. 38

    Bonnoli, G., Ghisellini, G., Foschini, L., Tavecchio, F. & Ghirlanda, G. The γ-ray brightest days of the blazar 3C 454.3. Mon. Not. R. Astron. Soc. 410, 368–380 (2011)

  39. 39

    Ghisellini, G. & Tavecchio, F. Canonical high-power blazars. Mon. Not. R. Astron. Soc. 397, 985–1002 (2009)

  40. 40

    Nalewajko, K., Begelman, M. C. & Sikora, M. Constraining the location of gamma-ray flares in luminous blazars. Astrophys. J. 789, 161 (2014)

  41. 41

    Böttcher, M., Reimer, A., Sweeney, K. & Prakash, A. Leptonic and hadronic modeling of Fermi-detected blazars. Astrophys. J. 768, 54 (2013)

  42. 42

    Bentz, M. C., Peterson, B. M., Pogge, R. W., Vestergaard, M. & Onken, C. A. The radius–luminosity relationship for active galactic nuclei: the effect of host–galaxy starlight on luminosity measurements. Astrophys. J. 644, 133–142 (2006)

  43. 43

    Koshida, S., Minezaki, T. & Yoshii, Y. et al. Reverberation measurements of the inner radius of the dust torus in 17 Seyfert galaxies. Astrophys. J. 788, 159 (2014)

  44. 44

    Dermer, C. On the beaming statistics of γ-ray sources. Astrophys. J. 446, L63–L66 (1995)

  45. 45

    Sikora, M. & Madejski, G. On pair content and variability of subparsec jets in quasars. Astrophys. J. 534, 109–113 (2000)

  46. 46

    Tavecchio, F., Maraschi, L. & Ghisellini, G. Constraints on the physical parameters of TeV blazars. Astrophys. J. 509, 608–619 (1998)

  47. 47

    Ghisellini, G. & Celotti, A. Relativistic large-scale jets and minimum power requirements. Mon. Not. R. Astron. Soc. 327, 739–743 (2001)

  48. 48

    Ghisellini, G. & Madau, P. On the origin of the γ-ray emission in blazars. Mon. Not. R. Astron. Soc. 280, 67–76 (1996)

  49. 49

    Ghisellini, G. Electron-positron pairs in blazar jets and γ-ray loud radio galaxies. Mon. Not. R. Astron. Soc. 424, L26–L30 (2012)

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F.T. and L.M. acknowledge partial funding through a PRIN–INAF 2011 grant.

Author information

G.G. wrote the manuscript and fitted all blazars presented. F.T., L.M., A.C. and T.S. contributed to the discussion of the implications of the results.

Correspondence to G. Ghisellini.

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Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Jet power versus radiative jet power.

We compare the total jet power and the radiative jet power for the blazars in our sample. The grey lines, as labelled, respectively correspond to equality and to Pjet equal to 10-fold and 100-fold Prad. Same symbols as in Fig. 1. The average error bar is indicated.

Extended Data Figure 2 Distribution of relevant quantities.

a, Normalized redshift distribution for FSRQs (light hatching) and BL Lacs (heavy hatching) in our sample. b, Normalized distribution of the ratio log(Ldisk/LEdd) for FSRQs in our sample. The black hole mass is the virial mass, calculated on the basis of the width of the broad lines12, compared with a log-normal distribution having a width of σ = 0.35 dex. c, Distribution of the bulk Lorentz factor. Hatching as in a. The plotted normal distribution has a width of σ = 1.4. d, Distribution of the ratio log(Pjet/Ldisk) for our sources, including BL Lacs (hatching as in a). The shown log-normal distribution has a width of σ = 0.48 dex.

Extended Data Figure 3 Distribution of jet powers.

Jet power distribution for FSRQs (light hatching) and BL Lacs (heavy hatching) in our sample, compared with the disk luminosity distribution as labelled: Pp is the kinetic power of the (cold) protons, assuming one proton per emitting electron; Pe is the power in relativistic emitting electrons; PB is the jet Poynting flux; Prad is the power that the jet has spent in producing the observed radiation; Ldisk is the luminosity of the accretion disk. All distributions are fitted with a log-normal distribution. The corresponding value of σ (in dex) is reported. The average values of the distributions are 〈log(Ldisk)〉 = 45.5, 〈log(Prad)〉 = 45.3, 〈log(PB)〉 = 45.0, 〈log(Pe)〉 = 44.4, 〈log(Pp)〉 = 46.4 (units of luminosity and power are erg s−1).

Supplementary information

Supplementary Table 1

This table contains relevant parameters of the blazars in this study. Col. 1 and Col. 2: AR and Dec (J2000); Col. 3: redshift; Col. 4 – Col. 7: Logarithm of Prad, Pe, PB, Pp (powers in units of erg s1); Col. 8: bulk Lorentz factor; Col. 9: viewing angle in degrees; Col. 10: Logarithm of the disk luminosity (in units of erg s1) as resulting from disk fitting; Col. 11: Logarithm of the disk luminosity (in units of erg s1) as measured from the broad emission lines; Col. 12 – Col. 14: logarithm of the black hole mass (in units of the solar mass) estimated through the virial method12 using the H (Col. 12), MgII (Col. 13) and CIV (Col. 14) broad emission lines. (XLSX 90 kb)

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Ghisellini, G., Tavecchio, F., Maraschi, L. et al. The power of relativistic jets is larger than the luminosity of their accretion disks. Nature 515, 376–378 (2014).

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