Stochastic Acceleration in the Western Hotspot of Pictor A

Abstract

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 hotspot of Pictor A as an example to demonstrate the model characteristics, which may be tested with high energy observations.

12 pages, 2 figures. Accepted by ApJ Letters

References in corpus (3)

• New results on particle acceleration in the Centaurus A jet and counterjet from a deep Chandra observation
• A Chandra study of particle acceleration in the multiple hotspots of nearby radio galaxies
• Radio Lobes of Pictor A: an X-ray spatially resolved Study

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• Origin of the X-rays and Possible GeV-TeV Emission from the Western Hot Spot Of Pictor A
• A numerical study of the interplay between Fermi acceleration mechanisms in radio lobes of FR-II radio galaxies
• X-ray Spectral Analysis of the Jet Termination Shock in Pictor A on Sub-Arcsecond Scales with Chandra
• Numerical modeling and physical interplay of stochastic turbulent acceleration for non-thermal emission processes