Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A two-component jet model for the tidal disruption event Swift
  J164449.3+573451   We analyze both the early and late time radio and X-ray data of the tidal
disruption event Swift J1644+57. The data at early times ($\lesssim 5$ days)
necessitates 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
$\Gamma \approx 15$, while the outer jet is trans-relativistic, with $\Gamma
\lesssim 1.2$. 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 tidal
disruption events can be tested by future observations.

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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph