Dr Philip G. Edwards (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA))

Constantly variable, or variably constant? - Dr Philip G. Edwards Colloquium

ATNF Marsfield Lecture Theatre

Abstract

Extragalactic radio sources can be classified in many ways:
in this talk we'll look at two distinct classes, the
variably constant and the constantly variable.
Recent searches for GHz-peaked spectrum (GPS) sources will
be described. Selected primarily based on
their radio spectrum, GPS sources range from low-redshift
galaxies, which often show signs of recent merger activity,
to (an over-abundance of) high redshift quasars.
The polarization and (non-)variability properties of both classes
will be examined. The talk will then switch to intraday variable
sources, at the opposite extreme of radio variability,
via an brief examination of a reported GPS source which has
subsequently been found to display IDV. A detailed study of
another IDV source, J0509+0541, will also be made in the
light of its association with a EGRET gamma-ray source.