The extended TeV gamma-ray source ARGO J2031+4157 (or MGRO J2031+41) is positionally consistent with the Cygnus Cocoon discovered by Fermi-LAT at GeV energies in the Cygnus superbubble. Reanalyzing the ARGO-YBJ data collected from 2007 November to 2013 January, the angular extension and energy spectrum of ARGO J2031+4157 are evaluated. After subtracting the contribution of the overlapping TeV sources, the ARGO-YBJ excess map is fitted with a two-dimensional Gaussian function in a square region of 10◦ × 10◦, finding a source extension σext= 1. ◦ 8 ± 0. ◦ 5. The observed differential energy spectrum is dN/dE = (2.5 ± 0.4) × 10−11(E/1TeV)−2.6±0.3 photons cm−2 s−1 TeV−1, in the energy range 0.2–10 TeV. The angular extension is consistent with that of the Cygnus Cocoon as measured by Fermi-LAT and the spectrum also shows a good connection with the one measured in the 1–100 GeV energy range. These features suggest to identify ARGO J2031+4157 as the counterpart of the Cygnus Cocoon at TeV energies. The Cygnus Cocoon, located in the star-forming region of Cygnus X, is interpreted as a cocoon of freshly accelerated cosmic rays related to the Cygnus superbubble. The spectral similarity with supernova remnants (SNRs) indicates that the particle acceleration inside a superbubble is similar to that in an SNR. The spectral measurements from 1 GeV to 10 TeV allows for the first time to determine the possible spectrum slope of the underlying particle distribution. A hadronic model is adopted to explain the spectral energy distribution.

B., B., 2, ., P., B., 4, ., X. J., B., P., B., et al. (2014). IDENTIFICATION OF THE TeV GAMMA-RAY SOURCE ARGO J2031+4157 WITH THE CYGNUS COCOON. THE ASTROPHYSICAL JOURNAL, 790, 152-156 [10.1088/0004-637X/790/2/152].

IDENTIFICATION OF THE TeV GAMMA-RAY SOURCE ARGO J2031+4157 WITH THE CYGNUS COCOON

MARI, Stefano Maria;P. Montini6;
2014-01-01

Abstract

The extended TeV gamma-ray source ARGO J2031+4157 (or MGRO J2031+41) is positionally consistent with the Cygnus Cocoon discovered by Fermi-LAT at GeV energies in the Cygnus superbubble. Reanalyzing the ARGO-YBJ data collected from 2007 November to 2013 January, the angular extension and energy spectrum of ARGO J2031+4157 are evaluated. After subtracting the contribution of the overlapping TeV sources, the ARGO-YBJ excess map is fitted with a two-dimensional Gaussian function in a square region of 10◦ × 10◦, finding a source extension σext= 1. ◦ 8 ± 0. ◦ 5. The observed differential energy spectrum is dN/dE = (2.5 ± 0.4) × 10−11(E/1TeV)−2.6±0.3 photons cm−2 s−1 TeV−1, in the energy range 0.2–10 TeV. The angular extension is consistent with that of the Cygnus Cocoon as measured by Fermi-LAT and the spectrum also shows a good connection with the one measured in the 1–100 GeV energy range. These features suggest to identify ARGO J2031+4157 as the counterpart of the Cygnus Cocoon at TeV energies. The Cygnus Cocoon, located in the star-forming region of Cygnus X, is interpreted as a cocoon of freshly accelerated cosmic rays related to the Cygnus superbubble. The spectral similarity with supernova remnants (SNRs) indicates that the particle acceleration inside a superbubble is similar to that in an SNR. The spectral measurements from 1 GeV to 10 TeV allows for the first time to determine the possible spectrum slope of the underlying particle distribution. A hadronic model is adopted to explain the spectral energy distribution.
2014
B., B., 2, ., P., B., 4, ., X. J., B., P., B., et al. (2014). IDENTIFICATION OF THE TeV GAMMA-RAY SOURCE ARGO J2031+4157 WITH THE CYGNUS COCOON. THE ASTROPHYSICAL JOURNAL, 790, 152-156 [10.1088/0004-637X/790/2/152].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/116278
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