Detection of very-high-energy γ-ray emission from the vicinity of PSR B 1706 − 44 and G 343 . 1 − 2 . 3 with H .

Theγ-ray pulsar PSR B1706 −44 and the adjacent supernova remnant (SNR) candidate G 343. 1−2. were observed by H.E.S.S. during a dedicated observation campaign in 2007. As a result of this observatio n campaign, a new source of very-high-energy (VHE; E > 100 GeV)γ-ray emission, HESS J1708 −443, was detected with a statistical significance of 7 σ, although no significant point-like emission was detected a t the position of the energetic pulsar itself. In this paper, the morphologic al and spectral analyses of the newly-discovered TeV source are presented. The centroid of HESS J1708 −443 is considerably o ffset from the pulsar and located near the apparent center of th e SNR, atαJ2000 = 17h08m11s ± 17s and δJ2000 = −44◦20′ ± 4′. The source is found to be significantly more extended than th e H.E.S.S. point spread function ( ∼0.1◦), with an intrinsic Gaussian width of 0.29 ◦ ± 0.04◦. Its integral flux between 1 and 10 TeV is ∼ 3.8× 10−12 ph cm−2 s−1, equivalent to 17% of the Crab Nebula flux in the same energy range. The measured energy spectrum is wel l-fit by a power law with a relatively hard photon index Γ = 2.0± 0.1stat± 0.2sys. Additional multi-wavelength data, including 330 MHz VLA ob servations, were used to investigate the VHE γ-ray source’s possible associations with the pulsar wind nebula of PSR B1706 −44 and/or with the complex radio structure of the partial shell-typ e SNR G 343.1 −2.3.