The \gamma -ray spectrum of the low-frequency-peaked BL Lac ( LBL ) object AP Librae is studied , following the discovery of very-high-energy ( VHE ; E > 100 { GeV } ) \gamma -ray emission up to the TeV range by the H.E.S.S .
experiment .
This makes AP Librae one of the few VHE emitters of the LBL type .
The measured spectrum yields a flux of ( 8.8 \pm 1.5 _ { stat } \pm 1.8 _ { sys } ) \times 10 ^ { -12 } { cm } ^ { -2 } { s } ^ % { -1 } above 130 GeV and a spectral index of \Gamma = 2.65 \pm 0.19 _ { stat } \pm 0.20 _ { sys } .
This study also makes use of Fermi -LAT observations in the high energy ( HE , E > 100 MeV ) range , providing the longest continuous light curve ( 5 years ) ever published on this source .
The source underwent a flaring event between MJD 56306-56376 in the HE range , with a flux increase of a factor 3.5 in the 14-day bin light curve and no significant variation in spectral shape with respect to the low-flux state .
While the H.E.S.S .
and ( low state ) Fermi -LAT fluxes are in good agreement where they overlap , a spectral curvature between the steep VHE spectrum and the Fermi -LAT spectrum is observed .
The maximum of the \gamma -ray emission in the spectral energy distribution is located below the GeV energy range .