Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Locations of optical and $\gamma$-ray emitting regions in the jet of PMN
  J2345-1555   We collect long term $\gamma$-ray, optical and radio $15$ GHz light curves of
quasar object PMN J2345-1555. The correlation analyses between them are
performed via the local cross-correlation function (LCCF). We found that all
the optical $V$, $R$ band and the infrared $J$ band are correlated with the
radio 15 GHz at beyond $3\sigma$ significance level, and the lag times are
$-221.81^{+6.26}_{-6.72}$, $-201.38^{+6.42}_{-6.02}$ and
$-192.27^{+8.26}_{-7.37}$ days, respectively. The $\gamma$-ray is strongly
correlated with optical, but weakly correlated with the radio. We present that
time lags between different frequencies can be used as an alternative parameter
to derive the core-shift measurement. For this target, the magnetic field and
particle density at 1 parsec in jet are derived to be $0.61$ Gauss and
$1533/\gamma_{\rm min}$ cm$^{-3}$, respectively. The black hole mass and the 15
GHz core position in jet are estimated to be $10^{8.44} {\rm M}_{\odot}$ and
$30$ parsec, respectively. The lag times enable us to derive that the optical
and the $\gamma$-ray emitting regions coincide, which are located at
$4.26^{+0.83}_{-0.79}$ pc away from 15 GHz core position in jet and beyond the
broad line region (BLR). We found that a $3\sigma$ correlation between the
color index and the radio light curve, which indicates that opacity may play an
important role in the variation. The $\delta V-\delta R$ behaviors are complex,
while the $R-J$ shows a bluer when brighter trend. As hinted from radio images,
we proposed a positional dependent spectral index model to explain the color
index behaviors, which is complementary for the shock in jet model. The
curvature effects and contribution from accretion disk may also affect
variables of blazars in many aspects.

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The categories of this paper are: hep-ex
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The categories of this paper are: physics
27
The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: alg-geom