Discovery of very-high-energy γ-ray emission from the vicinity of PSR J1913+1011 with HESS

The HESS experiment, an array of four Imaging Atmospheric Cherenkov Telescopes with high sensitivity and large field-of-view, has been used to search for emitters of very-high-energy (VHE, >100 GeV) γ-rays along the Galactic plane, covering the region 30° < l < 60°, 280° < l < 330°, and -3° < b < 3°. In this continuation of the HESS Galactic Plane Scan, a new extended VHE γ-ray source was discovered at α₂₀₀₀=19^h12^m49^s, δ₂₀₀₀=+10°09’06” (HESS J1912+101). Its integral flux between 1-10 TeV is ~10% of the Crab Nebula flux in the same energy range. The measured energy spectrum can be described by a power law dN/dE ∼ E^-Γ with a photon index Γ = 2.7 ± 0.2_stat± 0.3_sys. HESS J1912+101 is plausibly associated with the high spin-down luminosity pulsar PSR J1913+1011. We also discuss associations with an as yet unconfirmed SNR candidate proposed from low frequency radio observation and/or with molecular clouds found in ¹³CO data.