Examples of extreme intraday variability
Authors: Kedziora-Chudczer L.1; Jauncey D.L.2; Wieringa M.A.3; Tzioumis A.K.4; Bignall H.E.5
Source: Astrophysics and Space Science, Volume 278, Numbers 1-2, 2001 , pp. 113-117(5)
Publisher: Springer
Abstract:
We present results of the ATCA IDV Survey of southern extragalactic radio sources. We discuss briefly the properties of the 22 new intraday variable sources discovered in the Survey. The follow-up observations of a few extreme examples of strong intraday variability are presented. We find that the characteristics of the total flux density fluctuations at different wavelengths are consistent with intersteller scintillations (ISS) of the microarcsecondsize soorten components. However, the scintillating components of a few extreme IDVs are characterized by the brightness temperaturen far exceeding the T=10^12 K limit. The relativistic beaming invoked in such sources would require Doppler factors up to as high as 
10^3.
Language: English
Document Type: Regular paper
Affiliations: 1: Australia Telescope National Facility, Australia E-mail:lkedzior@atnf.csiro.au 2: Australia Telescope National Facility, Australia E-mail:djauncey@atnf.csiro.au 3: Australia Telescope National Facility, Australia E-mail:mwiering@atnf.csiro.au 4: Australia Telescope National Facility, Australia E-mail:atzioum@atnf.csiro.au 5: University of Adelaide, Australia; E-mail: hbignall@atnf.csiro.au

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