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A population of highly energetic transient events in the centres of active galaxies


Recent all-sky surveys have led to the discovery of new types of transients. These include stars disrupted by the central supermassive black hole, and supernovae that are 10–100 times more energetic than typical ones. However, the nature of even more energetic transients that apparently occur in the innermost regions of their host galaxies is hotly debated1,2,3. Here we report the discovery of the most energetic of these to date: PS1-10adi, with a total radiated energy of ~2.3 × 1052 erg. The slow evolution of its light curve and persistently narrow spectral lines over  3 yr are inconsistent with known types of recurring black hole variability. The observed properties imply powering by shock interaction between expanding material and large quantities of surrounding dense matter. Plausible sources of this expanding material are a star that has been tidally disrupted by the central black hole, or a supernova. Both could satisfy the energy budget. For the former, we would be forced to invoke a new and hitherto unseen variant of a tidally disrupted star, while a supernova origin relies principally on environmental effects resulting from its nuclear location. Remarkably, we also discover that PS1-10adi is not an isolated case. We therefore surmise that this new population of transients has previously been overlooked due to incorrect association with underlying central black hole activity.

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Fig. 1: Absolute magnitude M λ (Vega system) light curves of PS1-10adi.
Fig. 2: Evolution of the continuum-subtracted Hα line profile of PS1-10adi at selected epochs.
Fig. 3: Pseudobolometric JHK-, UBVRI- and UBVRIJHK-band and blackbody luminosity evolution of PS1-10adi.
Fig. 4: Sample of PS1-10adi-like transients.


  1. Drake, A. J. et al. The discovery and nature of the optical transient CSS100217:102913+404220. Astrophys. J. 735, 106–127 (2011).

    ADS  Article  Google Scholar 

  2. Dong, S. et al. ASASSN-15lh: a highly super-luminous supernova. Science 351, 257–260 (2016).

    ADS  Article  Google Scholar 

  3. Leloudas, G. et al. The superluminous transient ASASSN-15lh as a tidal disruption event from a Kerr black hole. Nat. Astron. 1, 0002 (2016).

    Article  Google Scholar 

  4. Inserra, C. et al. Super-luminous type Ic supernovae: catching a magnetar by the tail. Astrophys. J. 770, 128–155 (2013).

    ADS  Article  Google Scholar 

  5. Abazajian, K. N. et al. The seventh data release of the Sloan Digital Sky Survey. Astrophys. J. Suppl. 182, 543–558 (2009).

    ADS  Article  Google Scholar 

  6. Dessart, L., Audit, E. & Hillier, D. J. Numerical simulations of superluminous supernovae of type IIn. Mon. Not. R. Astron. Soc. 449, 4304–4325 (2015).

    ADS  Article  Google Scholar 

  7. Osterbrock, D. E. & Pogge, R. W. The spectra of narrow-line Seyfert 1 galaxies. Astrophys. J. 297, 166–176 (1985).

    ADS  Article  Google Scholar 

  8. Schlegel, E. M. A new subclass of type II supernovae? Mon. Not. R. Astron. Soc. 244, 269–271 (1990).

    ADS  Google Scholar 

  9. Ulrich, M.-H., Maraschi, L. & Urry, C. M. Variability of active galactic nuclei. Annu. Rev. Astron. Astrophys. 35, 445–502 (1997).

    ADS  Article  Google Scholar 

  10. Fransson, C. et al. High-density circumstellar interaction in the luminous type IIn SN 2010jl: the first 1100 days. Astrophys. J. 797, 118–157 (2014).

    ADS  Article  Google Scholar 

  11. Rees, M. J. Tidal disruption of stars by black holes of 106–108 solar masses in nearby galaxies. Nature 333, 523–528 (1988).

    ADS  Article  Google Scholar 

  12. MacLeod, C. L. et al. A description of quasar variability measured using repeated SDSS and POSS imaging. Astrophys. J. 753, 106–126 (2012).

    ADS  Article  Google Scholar 

  13. MacLeod, C. L. et al. A systematic search for changing-look quasars in SDSS. Mon. Not. R. Astron. Soc. 457, 389–404 (2016).

    ADS  Article  Google Scholar 

  14. Netzer, H. in Active Galactic Nuclei (eds Blandford, R. D., & Netzer, H. et al.) 57–158 (Springer, Berlin, 1990).

  15. Denney, K. D., Peterson, B. M., Dietrich, M., Vestergaard, M. & Bentz, M. C. Systematic uncertainties in black hole masses determined from single-epoch spectra. Astrophys. J. 692, 246–264 (2009).

    ADS  Article  Google Scholar 

  16. Vanden Berk, D. E. et al. Composite quasar spectra from the Sloan Digital Sky Survey. Astron. J. 122, 549–564 (2001).

    ADS  Article  Google Scholar 

  17. Phinney, E. S. in The Center of the Galaxy (ed. Morris, M.) 543–553 (Kluwer Academic, 1989).

  18. Gezari, S. et al. An ultraviolet-optical flare from the tidal disruption of a helium-rich stellar core. Nature 485, 217–220 (2012).

    ADS  Article  Google Scholar 

  19. Arcavi, I. et al. A continuum of H- to He-rich tidal disruption candidates with a preference for E+A galaxies. Astrophys. J. 793, 38–53 (2014).

    ADS  Article  Google Scholar 

  20. Loeb, A. & Ulmer, A. Optical appearance of the debris of a star disrupted by a massive black hole. Astrophys. J. 489, 573–578 (1997).

    ADS  Article  Google Scholar 

  21. Chevalier, R. A. & Fransson, C. Emission from circumstellar interaction in normal type II supernovae. Astrophys. J. 420, 268–285 (1994).

    ADS  Article  Google Scholar 

  22. Portegies Zwart, S. F. & van den Heuvel, E. P. J. A runaway collision in a young star cluster as the origin of the brightest supernova. Nature 450, 388–389 (2007).

    ADS  Article  Google Scholar 

  23. van den Heuvel, E. P. J. & Portegies Zwart, S. F. Are superluminous supernovae and long GRBs the products of dynamical processes in young dense star clusters? Astrophys. J. 779, 114–122 (2013).

    ADS  Article  Google Scholar 

  24. Mackey, J. et al. Interacting supernovae from photoionization-confined shells around red supergiant stars. Nature 512, 282–285 (2014).

    ADS  Article  Google Scholar 

  25. Metzger, B. D. & Stone, N. C. A bright year for tidal disruptions. Mon. Not. R. Astron. Soc. 461, 948–966 (2016).

    ADS  Article  Google Scholar 

  26. Bennett, C. L., Larson, D., Weiland, J. L. & Hinshaw, G. The 1% concordance Hubble constant. Astrophys. J. 794, 135–142 (2014).

    ADS  Article  Google Scholar 

  27. Schlafly, E. F. & Finkbeiner, D. P. Measuring reddening with Sloan Digital Sky Survey stellar spectra and recalibrating SFD. Astrophys. J. 737, 103–115 (2011).

    ADS  Article  Google Scholar 

  28. Valenti, S. et al. SN 2009jf: a slow-evolving stripped-envelope core-collapse supernova. Mon. Not. R. Astron. Soc. 416, 3138–3159 (2011).

    ADS  Article  Google Scholar 

  29. Tonry, J. L. et al. The Pan-STARRS1 photometric system. Astrophys. J. 750, 99–112 (2012).

    ADS  Article  Google Scholar 

  30. Jester, S. et al. The Sloan Digital Sky Survey view of the Palomar-Green Bright Quasar Survey. Astron. J. 130, 873–895 (2005).

    ADS  Article  Google Scholar 

  31. Gall, C. Rapid formation of large dust grains in the luminous supernova 2010jl. Nature 511, 326–329 (2014).

    ADS  Article  Google Scholar 

  32. Drake, A. J. et al. First results from the Catalina Real-Time Transient Survey. Astrophys. J. 696, 870–884 (2009).

    ADS  Article  Google Scholar 

  33. Kankare, E. et al. SN 2009kn—the twin of the type IIn supernova 1994W. Mon. Not. R. Astron. Soc. 424, 855–873 (2012).

    ADS  Article  Google Scholar 

  34. Kalberla, P. M. W. et al. The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI. Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections. Astron. Astrophys. 440, 775–782 (2005).

    ADS  Article  Google Scholar 

  35. Greene, J. E. & Ho, L. C. Estimating black hole masses in active galaxies using the Hα emission line. Astrophys. J. 630, 122–129 (2005).

    ADS  Article  Google Scholar 

  36. Baldwin, J. A., Ferland, G. J., Korista, K. T., Hamann, F. & Dietrich, M. The mass of quasar broad emission line regions. Astrophys. J. 582, 590–595 (2003).

    ADS  Article  Google Scholar 

  37. Véron-Cetty, M.-P. & Véron, P. A catalogue of quasars and active nuclei: 13th edition. Astron. Astrophys. 518, A10–A17 (2010).

    Article  Google Scholar 

  38. Lawrence, A. et al. Slow-blue nuclear hypervariables in PanSTARRS-1. Mon. Not. R. Astron. Soc. 463, 296–331 (2016).

    ADS  Article  Google Scholar 

  39. Smith, N. et al. SN 2006gy: discovery of the most luminous supernova ever recorded, powered by the death of an extremely massive star like η Carinae. Astrophys. J. 666, 1116–1128 (2007).

    ADS  Article  Google Scholar 

  40. Kewley, L. J., Groves, B., Kauffmann, G. & Heckman, T. The host galaxies and classification of active galactic nuclei. Mon. Not. R. Astron. Soc. 372, 961–976 (2006).

    ADS  Article  Google Scholar 

  41. Baldwin, J. A., Phillips, M. M. & Terlevich, R. Classification parameters for the emission-line spectra of extragalactic objects. Publ. Astron. Soc. Pac if. 93, 5–19 (1981).

    ADS  Article  Google Scholar 

  42. Quimby, R. M. et al. Hydrogen-poor superluminous stellar explosions. Nature 474, 487–489 (2011).

    ADS  Article  Google Scholar 

  43. Gal-Yam, A. Luminous supernovae. Science 337, 927–932 (2012).

    ADS  Article  Google Scholar 

  44. Kasen, D. & Bildsten, L. Supernova light curves powered by young magnetars. Astrophys. J. 717, 245–249 (2010).

    ADS  Article  Google Scholar 

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We thank G. Ferland, B. Müller, K. Nilsson, M.-Á. Pérez-Torres and K. Poppenhaeger for discussions. E.K. and R.K. acknowledge support from the Science and Technology Facilities Council (STFC; ST/L000709/1). M.F. acknowledges the support of a Royal Society–Science Foundation Ireland University Research Fellowship. This work was partly supported by the European Union FP7 programme through the European Research Council (ERC) grant number 320360. S.J.S acknowledges ERC grant 291222 and STFC grants ST/I001123/1 and ST/L000709/1. J.H. acknowledges financial support from the Finnish Cultural Foundation. C.R.-C. acknowledges support by the Ministry of Economy, Development and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, Chile, and from the Comisión Nacional de Investigación Científica y Tecnológica through the Fondo Nacional de Desarrollo Científico y Tecnológico grant 3150238. The PS1 surveys were made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max Planck Society and its participating institutes the Max Planck Institute for Astronomy, Heidelberg, and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Inc., the National Central University of Taiwan, the Space Telescope Science Institute, NASA (National Aeronautics and Space Administration) under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University and the Los Alamos National Laboratory. The Catalina Sky Survey is funded by NASA under Grant No. NNG05GF22G issued through the Science Mission Directorate Near-Earth Objects Observations Program. The Catalina Real-Time Transient Survey is supported by the US National Science Foundation under grants AST-0909182 and AST-1313422. This work is based on observations made with the NOT, the LT, the WHT, the WISE, Swift and the Karl G. Jansky Very Large Array.

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E.K. performed the data analysis and wrote the manuscript. R.K., S.M., P.L., M.J.W., M.F., A.L., S.J.S., W.P.S.M., S.J.H., C.I. and A.P. contributed to the physical interpretation. A.B. carried out follow-up observations with the WHT. C.R.-C. carried out the radio data reductions. J.H., T.K. and T.R. carried out follow-up observations with the NOT. S.V., K.W.S. and S.J.S. built the Pan-STARRS Transient Science Server hosted at Queen’s University Belfast. K.C.C., K.W.H., M.E.H., N.K., R.-P.K., E.A.M., J.L.T., R.J.W. and C.W. are PS1 builders.

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Correspondence to E. Kankare.

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Kankare, E., Kotak, R., Mattila, S. et al. A population of highly energetic transient events in the centres of active galaxies. Nat Astron 1, 865–871 (2017).

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