Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray Flux and Spectral Variability of Six TeV Blazars with
  \textit{NuSTAR}   We report the first results of timing and spectral studies of \textit{Nuclear
Spectroscopic Telescope Array (NuSTAR)} observations of six TeV emitting
high-frequency peaked blazars: 1ES 0347$-$121, 1ES 0414$+$009, RGB J0710$+$591,
1ES 1101$-$232, 1ES 1218$+$304 and H 2356-309. Two out of these six TeV
blazars, 1ES 1101$-$232 and 1ES 1218$+$304, showed strong evidence of intraday
variations in the 3--79 keV energy range during those observations. We also
found a hint of an intraday variability timescale of 23.5 ks in the light curve
of 1ES 1218$+$304 using an autocorrelation function analysis. We obtained
magnetic field $B \sim 0.03$ G, electron Lorentz factor $\gamma \sim 2.16
\times 10^6 $ and emission region size $R \sim 1.19 \times 10^{16} $ cm for 1ES
1218$+$304 using that variability timescale. The other blazars' light curves do
not show any variability timescales shorter than their observation lengths;
however, we note that the data were both noisier and sparser for them. We also
investigated the spectral shape of these TeV blazars and found that the
spectrum of 1ES 0414$+$009 is well described by a single power-law with photon
index $\Gamma \sim 2.77$. The spectra of the other five HBLs are somewhat
better represented by log-parabola models with local photon indices (at 10 keV)
$\alpha \sim 2.23-2.67$ and curvature parameters, $\beta \sim 0.27-0.43$.

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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys