The unidentified very-high-energy (VHE; E $>$ 0.1 TeV) $gamma$-ray source, HESS J1826$-$130, was discovered with the High Energy Stereoscopic System (HESS) in the Galactic plane. The analysis of 215 h of HESS data has revealed a steady $gamma$-ray flux from HESS J1826$-$130, which appears extended with a half-width of 0.21$^{circ}$ $pm$ 0.02$^{circ}_{text{stat}}$ $pm$ 0.05$^{circ}_{text{sys}}$. The source spectrum is best fit with either a power-law function with a spectral index $Gamma$ = 1.78 $pm$ 0.10$_{text{stat}}$ $pm$ 0.20$_{text{sys}}$ and an exponential cut-off at 15.2$^{+5.5}_{-3.2}$ TeV, or a broken power-law with $Gamma_{1}$ = 1.96 $pm$ 0.06$_{text{stat}}$ $pm$ 0.20$_{text{sys}}$, $Gamma_{2}$ = 3.59 $pm$ 0.69$_{text{stat}}$ $pm$ 0.20$_{text{sys}}$ for energies below and above $E_{rm{br}}$ = 11.2 $pm$ 2.7 TeV, respectively. The VHE flux from HESS J1826$-$130 is contaminated by the extended emission of the bright, nearby pulsar wind nebula (PWN), HESS J1825$-$137, particularly at the low end of the energy spectrum. Leptonic scenarios for the origin of HESS J1826$-$130 VHE emission related to PSR J1826$-$1256 are confronted by our spectral and morphological analysis. In a hadronic framework, taking into account the properties of dense gas regions surrounding HESS J1826$-$130, the source spectrum would imply an astrophysical object capable of accelerating the parent particle population up to $gtrsim$200 TeV. Our results are also discussed in a multiwavelength context, accounting for both the presence of nearby supernova remnants (SNRs), molecular clouds, and counterparts detected in radio, X-rays, and TeV energies.
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