We report the observation of a very high energy gamma-ray source whose position is coincident with HESS J1841−055. This source has been observed for 4.5 years by the ARGO-YBJ experiment from 2007 November to 2012 July. Its emission is detected with a statistical significance of 5.3 standard deviations. Parameterizing the source shape with a two-dimensional Gaussian function, we estimate an extension σ = (0.40+0.32−0.22)°, which is consistent with the HESS measurement. The observed energy spectrum is dN/dE=(9.0±1.6)×10**(−13) (E/5 TeV)**(− 2.32±0.23) photons cm−2 s−1 TeV−1, in the energy range 0.9–50 TeV. The integral gamma-ray flux above 1 TeV is 1.3±0.4 Crab, which is 3.2±1.0 times the flux derived by HESS. The differences in the flux determination between HESS and ARGO-YBJ and possible counterparts at other wavelengths are discussed.
OBSERVATION OF TeV GAMMA RAYS FROM THE UNIDENTIFIED SOURCE HESS J1841–055 WITH THE ARGO-YBJ EXPERIMENT
I. De Mitri;
2013-01-01
Abstract
We report the observation of a very high energy gamma-ray source whose position is coincident with HESS J1841−055. This source has been observed for 4.5 years by the ARGO-YBJ experiment from 2007 November to 2012 July. Its emission is detected with a statistical significance of 5.3 standard deviations. Parameterizing the source shape with a two-dimensional Gaussian function, we estimate an extension σ = (0.40+0.32−0.22)°, which is consistent with the HESS measurement. The observed energy spectrum is dN/dE=(9.0±1.6)×10**(−13) (E/5 TeV)**(− 2.32±0.23) photons cm−2 s−1 TeV−1, in the energy range 0.9–50 TeV. The integral gamma-ray flux above 1 TeV is 1.3±0.4 Crab, which is 3.2±1.0 times the flux derived by HESS. The differences in the flux determination between HESS and ARGO-YBJ and possible counterparts at other wavelengths are discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
