Spatially decomposed $\gamma$-ray features surrounding SNR Kes 79 & PSR J1853+0056
There have been substantial improvements on Fermi Large Area Telescope (LAT) data and analysis tools since the last analysis on the mid-aged supernova remnant (SNR) Kes 79 (Auchettl et al. 2014). Recent multi-wavelength studies confirmed its interaction with molecular clouds. About $0.36\degr$ north...
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Main Authors | , , , , , |
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Format | Journal Article |
Language | English |
Published |
09.12.2021
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Subjects | |
Online Access | Get full text |
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Summary: | There have been substantial improvements on Fermi Large Area Telescope (LAT)
data and analysis tools since the last analysis on the mid-aged supernova
remnant (SNR) Kes 79 (Auchettl et al. 2014). Recent multi-wavelength studies
confirmed its interaction with molecular clouds. About $0.36\degr$ north from
Kes 79, a powerful pulsar -- PSR J1853+0056 also deserves our attention. In
this work, we analyse the 11.5-year Fermi-LAT data to investigate the
$\gamma$-ray feature in/around this complex region. Our result shows a more
significant detection ($\sim$34.8$\sigma$ in 0.1--50 GeV) for this region. With
$\ge$5 GeV data, we detect two extended sources -- Src-N (the brighter one;
radius $\approx0.31\degr$) concentrated at the north of the SNR while enclosing
PSR J1853+0056, and Src-S (radius $\approx0.58\degr$) concentrated at the south
of the SNR. Their spectra have distinct peak energies ($\sim$1.0 GeV for Src-N
and $\lesssim$0.5 GeV for Src-S), suggesting different origins for them. In our
hadronic model that includes the leaked cosmic-rays (CRs) from the shock-cloud
collision, even with extreme values of parameters, SNR Kes 79 can by no means
provide enough CRs reaching clouds at Src-N to explain the local GeV spectrum.
We propose that the Src-N emission could be predominantly reproduced by a
putative pulsar wind nebula (PWN) powered by PSR J1853+0056. On the other hand,
our same hadronic model can reproduce a majority of the GeV emission at Src-S
with typical values of parameters, while the three known pulsars inside Src-S
release a total power that is too low to account for half of its $\gamma$-ray
emission. |
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DOI: | 10.48550/arxiv.2112.04875 |