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Cold, clumpy accretion onto an active supermassive black hole

Abstract

Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales1,2,3. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas4. Recent theory5,6,7 and simulations8,9,10 instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds—a departure from the ‘hot mode’ accretion model—although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma11,12,13. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy’s centre14, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core15. The observations show that these cold clouds also fuel black hole accretion, revealing ‘shadows’ cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations16 of warmer atomic gas at extremely high spatial resolution17, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it.

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Figure 1: A multiwavelength view of the Abell 2597 BCG.
Figure 2: ALMA observation of continuum-subtracted CO(2–1) emission in the Abell 2597 BCG.
Figure 3: ‘Shadows’ cast by molecular clouds moving towards the supermassive black hole.
Figure 4: Corroborating evidence that the inflowing molecular clouds must be in close proximity to the black hole.

References

  1. McNamara, B. R. & Nulsen, P. E. J. Heating hot atmospheres with active galactic nuclei. Annu. Rev. Astron. Astrophys. 45, 117–175 (2007)

    ADS  Article  Google Scholar 

  2. McNamara, B. R. & Nulsen, P. E. J. Mechanical feedback from active galactic nuclei in galaxies, groups and clusters. New J. Phys. 14, 055023 (2012)

    ADS  Article  Google Scholar 

  3. Fabian, A. C. Observational evidence of active galactic nuclei feedback. Annu. Rev. Astron. Astrophys. 50, 455–489 (2012)

    ADS  CAS  Article  Google Scholar 

  4. Bondi, H. On spherically symmetrical accretion. Mon. Not. R. Astron. Soc. 112, 195–204 (1952)

    ADS  MathSciNet  Article  Google Scholar 

  5. Pizzolato, F. & Soker, N. On the nature of feedback heating in cooling flow clusters. Astrophys. J. 632, 821–830 (2005)

    ADS  CAS  Article  Google Scholar 

  6. Voit, G. M., Donahue, M., Bryan, G. L. & McDonald, M. Regulation of star formation in giant galaxies by precipitation, feedback and conduction. Nature 519, 203–206 (2015)

    ADS  CAS  Article  Google Scholar 

  7. Voit, G. M., Bryan, G. L., O’Shea, B. W. & Donahue, M. Precipitation-regulated star formation in galaxies. Astrophys. J. 808, L30 (2015)

    ADS  Article  Google Scholar 

  8. Sharma, P., McCourt, M., Quataert, E. & Parrish, I. J. Thermal instability and the feedback regulation of hot haloes in clusters, groups, and galaxies. Mon. Not. R. Astron. Soc. 420, 3174–3194 (2012)

    ADS  Article  Google Scholar 

  9. Gaspari, M., Ruszkowski, M. & Oh, S. P. Chaotic cold accretion on to black holes. Mon. Not. R. Astron. Soc. 432, 3401–3422 (2013)

    ADS  Article  Google Scholar 

  10. Li, Y. & Bryan, G. L. Modeling active galactic nucleus feedback in cool-core clusters: the formation of cold clumps. Astrophys. J. 789, 153 (2014)

    ADS  Article  Google Scholar 

  11. McNamara, B. R. et al. Discovery of ghost cavities in the X-ray atmosphere of Abell 2597. Astrophys. J. 562, L149–L152 (2001)

    ADS  Article  Google Scholar 

  12. Clarke, T. E., Sarazin, C. L., Blanton, E. L., Neumann, D. M. & Kassim, N. E. Low-frequency radio observations of X-ray ghost bubbles in A2597: a history of radio activity in the core. Astrophys. J. 625, 748–753 (2005)

    ADS  CAS  Article  Google Scholar 

  13. Tremblay, G. R. et al. Multiphase signatures of active galactic nucleus feedback in Abell 2597. Mon. Not. R. Astron. Soc. 424, 1026–1041 (2012)

    ADS  Article  Google Scholar 

  14. Gaspari, M., Brighenti, F. & Temi, P. Chaotic cold accretion on to black holes in rotating atmospheres. Astron. Astrophys. 579, A62 (2015)

    ADS  Article  Google Scholar 

  15. Tremblay, G. R. et al. Residual cooling and persistent star formation amid active galactic nucleus feedback in Abell 2597. Mon. Not. R. Astron. Soc. 424, 1042–1060 (2012)

    ADS  CAS  Article  Google Scholar 

  16. O’Dea, C. P., Baum, S. A. & Gallimore, J. F. Detection of extended H I absorption toward PKS 2322–123 in Abell 2597. Astrophys. J. 436, 669–677 (1994)

    ADS  Article  Google Scholar 

  17. Taylor, G. B., O’Dea, C. P., Peck, A. B. & Koekemoer, A. M. H I Absorption toward the nucleus of the radio galaxy PKS 2322–123 in A2597. Astrophys. J. 512, L27–L30 (1999)

    ADS  CAS  Article  Google Scholar 

  18. O’Dea, C. P., Baum, S. A., Mack, J., Koekemoer, A. M. & Laor, A. Hubble Space Telescope STIS far-ultraviolet observations of the central nebulae in the cooling-core clusters A1795 and A2597. Astrophys. J. 612, 131–151 (2004)

    ADS  Article  Google Scholar 

  19. Oonk, J. B. R., Hatch, N. A., Jaffe, W., Bremer, M. N. & van Weeren, R. J. Far-ultraviolet emission in the A2597 and A2204 brightest cluster galaxies. Mon. Not. R. Astron. Soc. 414, 2309–2336 (2011)

    ADS  CAS  Article  Google Scholar 

  20. Tremblay, G. R. et al. Far-ultraviolet morphology of star-forming filaments in cool core brightest cluster galaxies. Mon. Not. R. Astron. Soc. 451, 3768–3800 (2015)

    ADS  CAS  Article  Google Scholar 

  21. Salomé, P. et al. A very extended molecular web around NGC 1275. Astron. Astrophys. 531, A85 (2011)

    Article  Google Scholar 

  22. Jaffe, W., Bremer, M. N. & Baker, K. H II and H2 in the envelopes of cooling flow central galaxies. Mon. Not. R. Astron. Soc. 360, 748–762 (2005)

    ADS  CAS  Article  Google Scholar 

  23. Salomé, P. et al. Cold molecular gas in the Perseus cluster core. Association with X-ray cavity, Hα filaments and cooling flow. Astron. Astrophys. 454, 437–445 (2006)

    ADS  Article  Google Scholar 

  24. Smith, E. P., Heckman, T. M. & Illingworth, G. D. Stellar dynamics of powerful radio galaxies. Astrophys. J. 356, 399–415 (1990)

    ADS  Article  Google Scholar 

  25. Larson, R. B. Turbulence and star formation in molecular clouds. Mon. Not. R. Astron. Soc. 194, 809–826 (1981)

    ADS  CAS  Article  Google Scholar 

  26. Solomon, P. M., Rivolo, A. R., Barrett, J. & Yahil, A. Mass, luminosity, and line width relations of Galactic molecular clouds. Astrophys. J. 319, 730–741 (1987)

    ADS  CAS  Article  Google Scholar 

  27. Wiklind, T. & Combes, F. Molecular absorption and its time variations in Centaurus A. Astron. Astrophys. 324, 51–64 (1997)

    ADS  CAS  Google Scholar 

  28. Espada, D. et al. Disentangling the circumnuclear environs of Centaurus A. II. On the nature of the broad absorption line. Astrophys. J. 720, 666–678 (2010)

    ADS  CAS  Article  Google Scholar 

  29. David, L. P. et al. Molecular gas in the X-ray bright group NGC 5044 as revealed by ALMA. Astrophys. J. 792, 94 (2014)

    ADS  Article  Google Scholar 

  30. Urry, C. M. & Padovani, P. Unified schemes for radio-loud active galactic nuclei. Publ. Astron. Soc. Pacif. 107, 803–845 (1995)

    ADS  Article  Google Scholar 

  31. Voit, G. M. & Donahue, M. A deep look at the emission-line nebula in Abell 2597. Astrophys. J. 486, 242 (1997)

    ADS  CAS  Article  Google Scholar 

  32. Bolatto, A. D., Wolfire, M. & Leroy, A. K. The CO-to-H2 conversion factor. Annu. Rev. Astron. Astrophys. 51, 207–268 (2013)

    ADS  CAS  Article  Google Scholar 

  33. McNamara, B. R. et al. A 1010 solar mass flow of molecular gas in the A1835 brightest cluster galaxy. Astrophys. J. 785, 44 (2014)

    ADS  Article  Google Scholar 

  34. Russell, H. R. et al. Massive molecular gas flows in the A1664 brightest cluster galaxy. Astrophys. J. 784, 78 (2014)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. We are grateful to the European ALMA Regional Centres, particularly those in Garching and Manchester, for their dedicated end-to-end support of data associated with this paper. We thank R. Larson for discussions. G.R.T. acknowledges support from National Aeronautics and Space Administration (NASA) through Einstein Postdoctoral Fellowship Award Number PF-150128, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. F.C. acknowledges the European Research Council (ERC) for the Advanced Grant Program no. 267399-Momentum. B.R.M. is supported by a grant from the Natural Sciences and Engineering Research Council of Canada. T.A.D. acknowledges support from a Science and Technology Facilities Council (STFC) Ernest Rutherford Fellowship. A.C.E. acknowledges support from STFC grant ST/L00075X/1. A.C.F. and H.R.R. acknowledge support from ERC Advanced Grant Program no. 340442-Feedback. M.N.B. acknowledges funding from the STFC. Basic research in radio astronomy at the Naval Research Laboratory is supported by 6.1 Base funding.

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Authors

Contributions

G.R.T. was principal investigator on the original proposal, performed the data analysis, and wrote the paper. J.B.R.O., T.A.D., R.G.M. and A.M. were substantially involved in planning both scientific and technical aspects of the proposal, while T.A.D. and R.G.M. contributed ALMA data reduction and analysis expertise once the data were obtained. J.B.R.O., F.C. and P.S. invested substantial time in analysis of the data. Substantial scientific feedback was also provided over many months by F.C., J.B.R.O., C.P.O., S.A.B., G.M.V., M.D., B.R.M., M.A.M., T.E.C., H.R., A.C.E. and A.C.F., while all other co-authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Grant R. Tremblay.

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The authors declare no competing financial interests.

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This paper makes use of the following ALMA data: ADS/JAO.ALMA#2012.1.00988.S.

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Tremblay, G., Oonk, J., Combes, F. et al. Cold, clumpy accretion onto an active supermassive black hole. Nature 534, 218–221 (2016). https://doi.org/10.1038/nature17969

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