Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic electrons and magnetic field of the M87 jet on ~ten
  Schwarzschild radii scale   We explore energy densities of magnetic field and relativistic electrons in
the M87 jet. Since the radio core at the jet base is identical to the optically
thick surface against synchrotron self absorption (SSA), the observing
frequency is identical to the SSA turnover frequency. As a first step, we
assume the radio core as a simple uniform sphere geometry. Using the observed
angular size of the radio core measured by the Very Long Baseline Array at 43
GHz, we estimate the energy densities of magnetic field ($U_{B}$) and
relativistic electrons ($U_{e}$) based on the standard SSA formula. Imposing
the condition that the Poynting power and relativistic electron one should be
smaller than the total power of the jet, we find that (i) the allowed range of
the magnetic field strength ($B_{tot}$) is from 1 G to 15 G, and that (ii) $1
times 10^{-5} < U_{e}/U_{B} < 6 times 10^{2}$ holds. The uncertainty of
$U_{e}/U_{B}$ comes from the strong dependence on the angular size of the radio
core and the minimum Lorentz factor of non-thermal electrons ($gamma_{e,min}$)
in the core. It is still open that the resultant energetics is consistent with
either the magnetohydrodynamic jet or with kinetic power dominated jet even on
~10 Schwarzschild radii scale.

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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio