A very rapid Extreme Scattering Event in the IDV source 0954+658

Abstract

Extreme Scattering Events (ESEs) are dramatic variations of the flux density at Gigahertz frequencies caused by ray path distortions within an isolated inhomogeneity ("plasma lens") in the interstellar medium. These events are characterized by a deep flux density minimum in the light curve with, in some cases, surrounding maxima. The variability time scales range from weeks to months. These phenomena show a strong frequency dependence, in which the variability amplitudes increase with wavelength. During an Intraday Variability (IDV) monitoring project (March 2000), a feature resembling an ESE-like event appeared in the variable light curve of 0954+658, however with a time scale of less than two days. We will discuss this effect and its implications for a better description of the interstellar medium.

arXiv comment6 pages, 7 PS files. Accepted for publication in PASA; based on a talk given at the workshop: "AGN variability across the Electromagnetic Spectrum", Sydney 2001

References in corpus (2)

• A Sample-oriented Catalogue of BL Lacertae Objects
• The Gaussian Plasma Lens in Astrophysics. Refraction

Cited by in corpus (8)

• Real-time detection of an extreme scattering event: constraints on Galactic plasma lenses
• VLBA observations of a rare multiple quasar imaging event caused by refraction in the interstellar medium
• Serendipitous VLBI detection of rapid, large-amplitude, intraday variability in QSO 1156+295
• A seasonal cycle and an abrupt change in the variability characteristics of the intraday variable source S4 0954+65
• The brightness temperature problem in extreme IDV quasars: a model for PKS 0405-385
• High frequency VLBI observations of the scatter broadened quasar B2005+403
• Observations of IntraDay Variable sources with the Effelsberg and Urumqi Radio Telescopes
• Influence of the Galactic gravitational field on the positional accuracy of extragalactic sources. II Observational appearances and detectability