AGILE study of the gamma-ray emission from the SNR G78.2+2.1 (Gamma Cygni). (arXiv:1905.01255v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Piano_G/0/1/0/all/0/1">G. Piano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cardillo_M/0/1/0/all/0/1">M. Cardillo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pilia_M/0/1/0/all/0/1">M. Pilia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Trois_A/0/1/0/all/0/1">A. Trois</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giuliani_A/0/1/0/all/0/1">A. Giuliani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bulgarelli_A/0/1/0/all/0/1">A. Bulgarelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parmiggiani_N/0/1/0/all/0/1">N. Parmiggiani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tavani_M/0/1/0/all/0/1">M. Tavani</a>
We present a study on the gamma-ray emission detected by the AGILE-GRID from
the region of the SNR G78.2+2.1 (Gamma Cygni). In order to investigate the
possible presence of gamma rays associated with the SNR below 1 GeV, it is
necessary to analyze the gamma-ray radiation underlying the strong emission
from the pulsar PSR J2021+4026, which totally dominates the field. An
“off-pulse” analysis has been carried out, by considering only the emission
related to the pulsar off-pulse phase of the AGILE-GRID light curve. We found
that the resulting off-pulsed emission in the region of the SNR – detected by
the AGILE-GRID above 400 MeV – partially overlaps the radio shell boundary. By
analyzing the averaged emission on the whole angular extent of the SNR, we
found that a lepton-dominated double population scenario can account for the
radio and gamma-ray emission from the source. In particular, the MeV-GeV
averaged emission can be explained mostly by Bremsstrahlung processes in a high
density medium, whereas the GeV-TeV radiation by both Bremsstrahlung (E < 250
GeV) and inverse Compton processes (E > 250 GeV) in a lower density medium.
We present a study on the gamma-ray emission detected by the AGILE-GRID from
the region of the SNR G78.2+2.1 (Gamma Cygni). In order to investigate the
possible presence of gamma rays associated with the SNR below 1 GeV, it is
necessary to analyze the gamma-ray radiation underlying the strong emission
from the pulsar PSR J2021+4026, which totally dominates the field. An
“off-pulse” analysis has been carried out, by considering only the emission
related to the pulsar off-pulse phase of the AGILE-GRID light curve. We found
that the resulting off-pulsed emission in the region of the SNR – detected by
the AGILE-GRID above 400 MeV – partially overlaps the radio shell boundary. By
analyzing the averaged emission on the whole angular extent of the SNR, we
found that a lepton-dominated double population scenario can account for the
radio and gamma-ray emission from the source. In particular, the MeV-GeV
averaged emission can be explained mostly by Bremsstrahlung processes in a high
density medium, whereas the GeV-TeV radiation by both Bremsstrahlung (E < 250
GeV) and inverse Compton processes (E > 250 GeV) in a lower density medium.
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