The extended gamma-ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for ~4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parameterizing the source shape with a two-dimensional Gauss function, we estimate an extension of σext = 0fdg49 ± 0fdg22, which is consistent with a previous measurement by the Cherenkov Array H.E.S.S. The observed energy spectrum is dN/dE = 6.1 ± 1.4 × 10–13 (E/4 TeV)–2.54 ± 0.36 photons cm–2 s–1 TeV–1, in the energy range of ~1-20 TeV. The measured gamma-ray flux is consistent with the results of the Milagro detector, but is ~2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ and recorded in four years of data support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity over 1 TeV ~ 1.8 times the luminosity of the Crab Nebula
OBSERVATION OF THE TeV GAMMA-RAY SOURCE MGRO J1908+06 WITH ARGO-YBJ
BOLOGNINO, IRENE;GIROLETTI, ELIO;LIGUORI, GIUSEPPE;SALVINI, PAOLA;
2012-01-01
Abstract
The extended gamma-ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for ~4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parameterizing the source shape with a two-dimensional Gauss function, we estimate an extension of σext = 0fdg49 ± 0fdg22, which is consistent with a previous measurement by the Cherenkov Array H.E.S.S. The observed energy spectrum is dN/dE = 6.1 ± 1.4 × 10–13 (E/4 TeV)–2.54 ± 0.36 photons cm–2 s–1 TeV–1, in the energy range of ~1-20 TeV. The measured gamma-ray flux is consistent with the results of the Milagro detector, but is ~2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ and recorded in four years of data support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity over 1 TeV ~ 1.8 times the luminosity of the Crab NebulaI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
