posted on 21.10.2019, 14:16by JS Bloom, D Giannios, BD Metzger, SB Cenko, DA Perley, NR Butler, NR Tanvir, AJ Levan, PTO Brien, LE Strubbe, FD Colle, E Ramirez-Ruiz, WH Lee, S Nayakshin, E Quataert, AR King, A Cucchiara, J Guillochon, GC Bower, AS Fruchter, AN Morgan, AJVD Horst
While gas accretion onto some massive black holes (MBHs) at the centers of galaxies actively powers luminous emission, the vast majority of MBHs are considered dormant. Occasionally, a star passing too near a MBH is torn apart by gravitational forces, leading to a bright panchromatic tidal disruption flare (TDF). While the high-energy transient Swift J164449.3+573451 ("Sw 1644+57") initially displayed none of the theoretically anticipated (nor previously observed) TDF characteristics, we show that the observations (Levan et al. 2011) suggest a sudden accretion event onto a central MBH of mass ~10^6-10^7 solar masses. We find evidence for a mildly relativistic outflow, jet collimation, and a spectrum characterized by synchrotron and inverse Compton processes; this leads to a natural analogy of Sw 1644+57 with a smaller-scale blazar. The phenomenologically novel Sw 1644+57 thus connects the study of TDFs and active galaxies, opening a new vista on disk-jet interactions in BHs and magnetic field generation and transport in accretion systems.
We thank R. Romani, C. McKee and L. Blitz for close reads of drafts of this work and for
helpful interactions. We are grateful to entire Swift team for work on their remarkable facilities that enabled discovery of this event. Swift, launched in November 2004, is a NASA
mission in partnership with the Italian Space Agency and the UK Space Agency. Swift is
managed by NASA Goddard. Penn State University controls science and flight operations
from the Mission Operations Center in University Park, Pennsylvania. Los Alamos National
Laboratory provides gamma-ray imaging analysis. JSB and his group were partially supported by grants NASA/NNX10AF93G, NASA/NNX10AI28G, and NSG/AST-100991. DG
acknowledges support from the Lyman Spitzer, Jr. Fellowship awarded by the Department
of Astrophysical Sciences at Princeton University. BDM is supported by NASA through
Einstein Postdoctoral Fellowship grant number PF9-00065 awarded by the Chandra X-ray
Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under
contract NAS8-03060. SBC wishes to acknowledge generous support from Gary & Cynthia
Bengier, the Richard & Rhoda Goldman fund, NASA/Swift grant NNX10AI21G, NASA
Fermi grant NNX10A057G, and NSF grant AST-0908886. WHL is supported in part by
CONACyT grant 83254. AJvdH was supported by NASA grant NNH07ZDA001-GLAST.