Correlation between optical and $\gamma$-ray flux variations in BL Lacs
We report here results on the analysis of correlated flux variations between the optical and GeV $\gamma$-ray bands in three bright BL Lac objects, namely AO\, 0235+164, OJ 287 and PKS 2155$-$304. This was based on the analysis of about 10 years of data from the {\it Fermi} Gamma-ray Space Telescope...
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Main Authors | , , , , |
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Format | Journal Article |
Language | English |
Published |
01.04.2021
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Subjects | |
Online Access | Get full text |
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Summary: | We report here results on the analysis of correlated flux variations between
the optical and GeV $\gamma$-ray bands in three bright BL Lac objects, namely
AO\, 0235+164, OJ 287 and PKS 2155$-$304. This was based on the analysis of
about 10 years of data from the {\it Fermi} Gamma-ray Space Telescope covering
the period between 08 August 2008 to 08 August 2018 along with optical data
covering the same period. For all the sources, during the flares analysed in
this work, the optical and $\gamma$-ray flux variations are found to be closely
correlated. From broad band spectral energy distribution modelling of different
epochs in these sources using the one zone leptonic emission model, we found
that the optical-UV emission is dominated by synchrotron emission from the jet.
The $\gamma$-ray emission in the low synchrotron peaked sources AO\, 0235+164
and OJ 287 are found to be well fit with external Compton (EC) component,
while, the $\gamma$-ray emission in the high synchrotron peaked source PKS
2155$-$304 is well fit with synchrotron self Compton component. Further we note
that the $\gamma$-ray emission during the high flux state of AO 0235+164
(epochs A and B) requires seed photons from both the dusty torus and broad line
region, while the $\gamma$-ray emission in OJ 287 and during epochs C and D of
AO\,0235+164 can be modelled by EC scattering of infra-red photons from the
torus. |
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DOI: | 10.48550/arxiv.2104.00402 |