27 GIUGNO 2017 ore 15:00

The Faint Extragalactic Radio Background

Dr. Tessa Vernstrom (University of Toronto - Canada)
The Faint Extragalactic Radio Background
Figure: This image shows extragalactic components of the 
radio background, from large to small. The background image is the
synchrotron cosmic web from a magneto hydrodynamic simulation (Dolag, K.).
The upper left shows the X-ray and radio emission in the Coma cluster
(Brown & Rudnick, 2010). And the lower right shows an artistic rendering
of an active galactic nuclei radio galaxy. The plot in the lower left
shows the approximate brightness of the sky background as a function of

The radio sky covers a large range of sources, from small single galaxies
to large clusters of galaxies and the space between them. These sources
consist of some of the most powerful objects in the Universe, as well
as diffuse weak emitters; all together these sources make up the Cosmic
Radio Background (CRB). Understanding the radio background tells us about
how galaxies have evolved over time, the different kinds of galaxy
populations, the star formation history of the Universe, and the role of
magnetism, as well as details of large-scale structure and clustering.
Advancements in radio telescopes and novel data analysis techniques now
allow us to push observational limits to new depths, probing fainter
galaxies and farther back in cosmic time.This talk will discuss the use of
some of these new data and statistical techniques (such as confusion
analysis and cross correlations) for studying point sources and source
counts as well as diffuse cluster emission and the synchrotron cosmic web.
I will contrast the benefits and challenges to statistical detections for
investigating the nature of the faint extragalactic components of the
radio sky.