Context : The observation of rapidly variable very high energy ( VHE ) gamma-rays from non-aligned active galactic nuclei ( AGNs ) , as reported from M87 , proves challenging for conventional theoretical acceleration and emission models .

Aims : Motivated by recent work on pulsar-type particle acceleration in M87 ( Neronov & Aharonian 2007 ) , we re-examine the centrifugal acceleration of particles by rotating jet magnetospheres in the vicinity of accreting supermassive black hole systems and analyze the energy constraints imposed for highly underluminous systems .

Methods : The maximum Lorentz factor for centrifugally accelerated electrons in the presence of inverse Compton losses , and the associated characteristic variability time scale , are determined .
Applications are presented for conditions expected to be present in the radio galaxy M87 , assuming accretion onto the central black hole to occur in an advection-dominated ( ADAF ) mode .

Results : We show that for a highly underluminous source like M87 , centrifugally accelerated electrons may reach Lorentz factors up to \gamma \sim ( 10 ^ { 7 } -10 ^ { 8 } ) , allowing inverse Compton ( Thomson ) upscattering of sub-mm disk photons to the TeV regime .
Upscattering of Comptonized disk photons results in a flat TeV spectrum L _ { \nu } \propto \nu ^ { - \alpha _ { c } } with spectral index \alpha _ { c } \simeq 1.2 .
The characteristic variability time scale is of the order r _ { L } / c , which in the case of M87 corresponds to \simeq 1.7 d for a typical light cylinder radius of r _ { L } \simeq 5 r _ { s } .

Conclusions : Centrifugal acceleration could provide a natural explanation for the challenging VHE emission features in M87 .
Our results suggest that some advection-dominated accreting ( non-blazar ) AGNs could well be observable VHE emitting sources .