Detection of Very High Energy radiation from HESS J1908+063 confirms the Milagro unidentified source MGRO J1908+06

TL;DR

This paper reports the detection of very high energy gamma-ray emission from HESS J1908+063, confirming its association with the Milagro source MGRO J1908+06, and discusses potential multi-wavelength counterparts and origins.

Contribution

First detection of >300 GeV gamma rays from HESS J1908+063 confirming the Milagro source MGRO J1908+06 with detailed spectral and positional analysis.

Findings

Detection at 10.9 sigma significance

Flux above 1 TeV measured as (3.76±0.29±0.75)×10^-12 ph cm^-2 s^-1

Spectral photon index Gamma = 2.10±0.07±0.2

Abstract

Detection of a gamma-ray source above 300 GeV is reported, confirming the unidentified source MGRO J1908+06, discovered by the Milagro collaboration at a median energy of 20 TeV. The source was observed during 27 h as part of the extension of the H.E.S.S. Galactic plane survey to longitudes >30degr. HESS J1908+063 is detected at a significance level of 10.9 s with an integral flux above 1 TeV of (3.76+-0.29stat+-0.75sys)x10^-12 ph cm^-2 s^-1, and a spectral photon index Gamma = 2.10+-0.07stat+-0.2sys. The positions and fluxes of HESS 1908+063 and MGRO J1908+06 are in good agreement. Possible counterparts at other wavelengths and the origin of the gamma-ray emission are discussed. The nearby unidentified GeV source, GRO J1908+0556 (GeV) which also remains unidentified and the new Fermi pulsar 0FGL J1907.5+0617, may be connected to the TeV source.