Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Directional limits on persistent gravitational waves from Advanced
  LIGO's first observing run   We employ gravitational-wave radiometry to map the gravitational waves
stochastic background expected from a variety of contributing mechanisms and
test the assumption of isotropy using data from Advanced LIGO's first observing
run. We also search for persistent gravitational waves from point sources with
only minimal assumptions over the 20 - 1726 Hz frequency band. Finding no
evidence of gravitational waves from either point sources or a stochastic
background, we set limits at 90% confidence. For broadband point sources, we
report upper limits on the gravitational wave energy flux per unit frequency in
the range $F_{\alpha,\Theta}(f) < (0.1 - 56) \times 10^{-8}$ erg cm$^{-2}$
s$^{-1}$ Hz$^{-1}$ (f/25 Hz)$^{\alpha-1}$ depending on the sky location
$\Theta$ and the spectral power index $\alpha$. For extended sources, we report
upper limits on the fractional gravitational wave energy density required to
close the Universe of $\Omega(f,\Theta) < (0.39-7.6) \times 10^{-8}$ sr$^{-1}$
(f/25 Hz)$^\alpha$ depending on $\Theta$ and $\alpha$. Directed searches for
narrowband gravitational waves from astrophysically interesting objects
(Scorpius X-1, Supernova 1987 A, and the Galactic Center) yield median
frequency-dependent limits on strain amplitude of $h_0 <$ (6.7, 5.5, and 7.0)
$\times 10^{-25}$ respectively, at the most sensitive detector frequencies
between 130 - 175 Hz. This represents a mean improvement of a factor of 2
across the band compared to previous searches of this kind for these sky
locations, considering the different quantities of strain constrained in each
case.

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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
2
The categories of this paper are: math
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an