Are Centaurus A and M87 TeV gamma-ray sources?

In this Letter, we identify Cen A and M87, two nearby Fanaroff-Riley class I (FR I) radio galaxies with high-energy-peaked BL Lac (HBL)-like objects by investigating their spectral energy distributions (SEDs). The SED peak of Cen A at similar to 150 keV, which was generally believed to be the peak of inverse Compton emission as in the case of 3C 273, is found to be actually the peak of synchrotron emission. The synchrotron emission of M87 peaks in the far-UV band. We summarize the properties of gamma -ray-loud blazars, especially those of TeV BL Lac objects, and generalize them to HBL-like FR I radio galaxies according to the unified scheme of BL Lac objects and FR I radio galaxies. We infer that Cen A may have a peak in its Compton component power output at similar to1 TeV and that M87 may have a Compton emission peak at similar to0.1 TeV. For Cen A, the estimated TeV gamma -ray flux during outburst is F(0.25-30 TeV) = 6.4 x 10(-9) ergs cm(-2) s(-1), and for M87, F(0.25-30 TeV) = 1.1 x 10(-11) ergs cm(-2) s(-1). Both fluxes are detectable by TeV detectors available today, and hence Cen A and M87 are TeV gamma -ray source candidates. By investigating the long-term variability, we predict that Cen A will undergo an outburst in the near future and will be detectable at the TeV gamma -ray energy range using the CANGAROO and the German-French-Italian experiment HESS TeV gamma -ray telescopes.