; Wang, Jian-Min] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China
; [Liu, Siming
; Fryer, Christopher L.
; Li, Hui] Los Alamos Natl Lab, Los Alamos, NM 87545 USA
; [Fryer, Christopher L.] Univ Arizona, Dept Phys, Tucson, AZ 85721 USA
Chandra's high-resolution observations of radio galaxies require a revisit of the relevant electron acceleration processes. Although the diffusive shock particle acceleration model may explain spectra of spatially unresolved sources, it encounters difficulties in explaining the structure and spectral properties of recently discovered Chandra X-ray features in several low-power radio sources. We argue that these observations strongly suggest stochastic electron acceleration by magnetized turbulence, and show that the simplest stochastic particle acceleration model with energy-independent acceleration and escape timescales can overcome most of these difficulties. We use the bright core of the western hot spot of Pictor A as an example to demonstrate the model characteristics, which may be tested with high-energy observations.