A two-component jet model for the tidal disruption event swift J164449.3+573451

Dangbo Liu, Asaf Pe'er, Abraham Loeb

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We analyze both the early- and late-time radio and X-ray data of the tidal disruption event (TDE) Swift J1644+57. The data at early times (≲5 days) necessitate separation of the radio and X-ray emission regions, either spatially or in velocity space. This leads us to suggest a two-component jet model, in which the inner jet is initially relativistic with Lorentz factor Γ ≈ 15, while the outer jet is trans-relativistic, with Γ ≲ 1.2. This model enables a self-consistent interpretation of the late-time radio data, both in terms of peak frequency and flux. We solve the dynamics, radiative cooling, and expected radiation from both jet components. We show that while during the first month synchrotron emission from the outer jet dominates the radio emission, at later times, radiation from ambient gas collected by the inner jet dominates. This provides a natural explanation to the observed re-brightening, without the need for late-time inner engine activity. After 100 days, the radio emission peak is in the optically thick regime, leading to a decay of both the flux and peak frequency at later times. Our model's predictions for the evolution of radio emission in jetted TDEs can be tested by future observations.

Original languageEnglish
Article number13
JournalAstrophysical Journal
Issue number1
StatePublished - 1 Jan 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.


FundersFunder number
National Aeronautics and Space AdministrationNNX08AL43G, NNA09DB30A
National Science FoundationAST-0907890, PHYS-1066293


    • Black hole physics
    • Galaxies: jets
    • Galaxies: nuclei
    • Radiation mechanisms: non-thermal


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