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Spectral fitting of the radio through hard X-ray emission of BL Lac objects has previously been used to predict their level of high-energy (GeV - TeV) emission. In this paper, we point out that such spectral fitting can have very large uncertainties with respect to predictions of the VHE emission. This is demonstrated with the example of W Comae. We show that the best currently available contemporaneous optical - X-ray spectrum of W Comae still allows for a large range of possible parameters, resulting in drastically different > 40 GeV fluxes. We find that all acceptable leptonic-model fits to the optical - X-ray emission of W Comae predict a cut-off of the high-energy emission around ~ 100 GeV. We suggest that detailed measurements and analysis of the soft X-ray variability of W Comae may be used to break the degeneracy in the choice of possible fit parameters, and thus allow a more reliable prediction of the VHE emission from this object. Using the available soft X-ray variability measured by BeppoSAX, we predict a > 40 GeV flux from W Comae of ~ (0.4 - 1) * 10^{-10} photons/(cm^2 s) with no significant emission at E > 100 GeV for a leptonic jet model. We compare our results concerning leptonic jet models with detailed predictions of the hadronic Synchrotron-Proton Blazar model. This hadronic model predicts > 40 GeV fluxes very similar to those found for the leptonic models, but results in > 100 GeV emission which should be clearly detectable with future high-sensitivity instruments like VERITAS. Thus, we suggest this object as a promising target for VHE gamma-ray and co-ordinated broadband observations to distinguish between leptonic and hadronic jet models for blazars.
We report the detection of very high-energy gamma-ray emission from the intermediate-frequency-peaked BL Lacertae object W Comae (z=0.102) by VERITAS. The source was observed between January and April 2008. A strong outburst of gamma-ray emission was
Blazars represent the most abundant class of high-energy extragalactic $gamma$-ray sources. The subset of blazars known as BL Lac objects is on average closer to Earth and characterized by harder spectra at high energy than the whole sample. The frac
Context. The study of BL Lac objects (BLL) detected in gamma-rays gives insights on the acceleration mechanisms in play in such systems and is also a valuable tool to constrain the density of the extragalactic background light. As their spectra are d
The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 ($z$=0.095) at high (HE; 100 MeV$<$E$<$300 GeV) and very high-energy (VHE; $E>100,{rm GeV}$) with the fer Large Area Telescope (LAT) and the High Energy Stereoscopic
(abridged) We present near-infrared Ks-band imaging of 13 high redshift (0.6 < z < 1.3) BL Lac objects. We clearly detect the host in eight objects, and marginally in three others. In all cases, the host galaxy is well represented by an r^1/4 surface