RADIO INTRA-DAY VARIABILITY: ANSWERS AND QUESTIONS
3 views 0 purchase
Course
RADIO INTRA-DAY VARIABILITY
Institution
RADIO INTRA-DAY VARIABILITY
2. Evidence for Interstellar Scintillation
In his discovery paper Heeschen (1984) concluded that the flickering is probably
not correlated with Galactic latitude, as might be expected for ISS, and suggested
both intrinsic and ISS as possible causes. A later re-examination of the original
Do...
Intra-Day Variability, Gravitational Lensing and
Polarization
Downloaded from https://www.cambridge.org/core. IP address: 34.228.24.229, on 23 May 2020 at 17:51:59, subject to the Cambridge Core terms of
use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0252921100000750
, RADIO INTRA-DAY VARIABILITY: ANSWERS AND QUESTIONS
DAVID L. JAUNCEY
Australia Telescope National Facility, CSIRO, Australia E-mail: djauncey@atnf.csiro.au
LUCYNA KEDZIORA-CHUDCZER
Australia Telescope National Facility, and Anglo-Australian Observatory, Epping NSW, Australia
E-mail: lkedz.ior@atnf.csiro.au
JAMES E.J. LOVELL
Australia Telescope National Facility, CSIRO, Australia; E-mail: jlovell@atnf.csiro.au
JEAN-PIERRE MACQUART
RCfTA, School of Physics, University of Sydney, NSW, Australia; E-mail: jpm@physics.usyd.edu.au
GEORGE D. NICOLSON
Harteheesthoek Radio Astronomy Observatory, Krugersdorp, South Africa
E-mail: george @ hartrao. ac. z,a
RICK A. PERLEY
National Radio Astronomy Observatory, Socorro, NM, U.S.A.; E-mail: rperley@nrao.edu
JOHN E. REYNOLDS
Australia Telescope National Facility, CSIRO, Australia; E-mail: jreynold@atnf.csiro.au
ANASTASIOS K. TZIOUMIS
Australia Telescope National Facility, CSIRO, Australia; E-mail: atz.ioumi@atnf.csiro.au
MARK H. WIERINGA
Australia Telescope National Facility, CSIRO, Australia; E-mail: mwiering@atnf.csiro.au
HAYLEY E. BIGNALL
Department of Physics and Mathematical Physics, University of Adelaide, SA, Australia
E-mail: hbignall®physics.adelaide.edu.au
Abstract. Intra-day variability (IDV) of active galactic nuclei (AGN) has been detected from gamma-
ray energies to radio wavelengths. At high energies, such variability appears to be intrinsic to the
sources themselves. However, at radio wavelengths, brightness temperatures as high as 10 to
102' K are encountered if the IDV is intrinsic to the source. We discuss here the accumulating evid-
ence showing that, at radio wavelengths where the highest brightness temperatures are encountered,
interstellar scintillation (ISS) is the principal mechanism causing IDV. While ISS reduces the implied
brightness temperatures, they still remain uncomfortably high.
1. Introduction
Since its discovery (Dent, 1965) the radio variability of extragalactic radio sources
has been a powerful indicator of the presence of compact source structure. Several
Downloaded from https://www.cambridge.org/core. IP address: 34.228.24.229, on 23 May 2020 at 17:51:59, subject to the Cambridge Core terms of
use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0252921100000750
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller TIFFACADEMICS. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $14.99. You're not tied to anything after your purchase.
