Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Spin of M87*   Now that the mass of the central black hole in the galaxy M87 has been
measured with great precision using different methods, the remaining parameter
of the Kerr metric that needs to be estimated is the spin a*. We have modeled
measurements of the average power of the relativistic jet and an upper limit to
the mass accretion rate onto the black hole with general relativistic
magnetohydrodynamic models of jet formation. This allows us to derive
constraints on a* and the black hole magnetic flux phi. We find a lower limit
on M87*'s spin and magnetic flux of a* > 0.4 and phi > 6 in the prograde case,
and a* > 0.5 and phi > 10 in the retrograde case, otherwise the black hole is
not able to provide enough energy to power the observed jet. These results
indicate that M87* has a moderate spin at minimum and disfavor a variety of
models typified by low values of phi known as ``SANE'', indicating that M87*
prefers the magnetically arrested disk state. We discuss how different
estimates of the jet power and accretion rate can impact a* and phi.

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The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg