The Microarcsecond Sky and Cosmic Turbulence

Abstract

Radio waves are imprinted with propagation effects from ionized media through which they pass. Owing to electron density fluctuations, compact sources (pulsars, masers, and compact extragalactic sources) can display a wide variety of scattering effects. These scattering effects, particularly interstellar scintillation, can be exploited to provide *superresolution*, with achievable angular resolutions (<~ 1 microarcsecond) far in excess of what can be obtained by very long baseline interferometry on terrestrial baselines. Scattering effects also provide a powerful sub-AU probe of the microphysics of the interstellar medium, potentially to spatial scales smaller than 100 km, as well as a tracer of the Galactic distribution of energy input into the interstellar medium through a variety of integrated measures. Coupled with future gamma-ray observations, SKA observations also may provide a means of detecting fainter compact gamma-ray sources. Though it is not yet clear that propagation effects due to the intergalactic medium are significant, the SKA will either detect or place stringent constraints on intergalactic scattering.

20 pages, 8 figures in 8 PostScript files, to appear in "Science with the Square Kilometer Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews (Elsevier: Amsterdam)

References in corpus (14)

• The Wisconsin H-Alpha Mapper Northern Sky Survey
• Compressible MHD Turbulence in Interstellar Plasmas
• Rapid Variability and Annual Cycles in the Characteristic Time-scale of the Scintillating Source PKS 1257-326
• Interstellar scintillation as the origin of rapid radio variability in the quasar J1819+3845
• First Results from MASIV: The Micro-Arcsecond Scintillation-Induced Variability Survey
• Imbalanced Weak MHD Turbulence
• Interstellar Scintillation of the Polarized Flux Density in Quasar, PKS 0405-385
• Annual modulation in the scattering of J1819+3845: peculiar plasma velocity and anisotropy
• Far Ultraviolet Spectroscopy of the Intergalactic and Interstellar Absorption Toward 3C 273
• Annual modulation in IDV of quasar 0917+624 due to Interstellar Scintillation
• Magnetic Fields and Ionized Gas in the inner Galaxy: An Outer Scale for Turbulence and the Possible Role of HII Regions
• Intra-Day Variability and the Interstellar Medium Towards 0917+624
• The Size of the Extragalactic Source J1801-231 and the Association of Pulsar PSR B1758-23 with the Supernova Remnant W28
• On the Enhanced Interstellar Scattering Toward B1849+005

Cited by in corpus (12)

• Astrophysical gyrokinetics: kinetic and fluid turbulent cascades in magnetized weakly collisional plasmas
• The Commensal Real-time ASKAP Fast Transients (CRAFT) survey
• A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz
• Cascades and Dissipative Anomalies in Compressible Fluid Turbulence
• Plasma Diagnostics of the Interstellar Medium with Radio Astronomy
• VLBA observations of a rare multiple quasar imaging event caused by refraction in the interstellar medium
• Time-domain and spectral properties of pulsars at 154 MHz
• Turbulence in the Intergalactic Medium
• Intensity interferometry: Optical imaging with kilometer baselines
• Scatter broadening of compact radio sources by the ionized intergalactic medium: Prospects for detection with Space VLBI and the SKA
• The Murchison Widefield Array Transients Survey (MWATS). A search for low frequency variability in a bright Southern hemisphere sample
• Microlensing in phase space II: Correlations analysis