Phenomenology of radio sources



The Planck satellite will measure the whole sky at high radio frequencies (or, in other words, at millimetre wavelengths). This way we get a catalog of all possible radio sources in the sky! So far all full-sky surveys like this have been at lower frequencies only. With the new high frequency Planck survey we can study the general radio properties of the sources, or concentrate on the behaviour of particular classes of sources. The aims of the project are the reduction of the data and the search and set up of source samples. The other radio sources related projects will directly benefit from this groundwork.

Planck will measure the spectrum, polarization, and variability of each source at several frequencies, and these will be combined with the data gathered before the launch. We also need accurate positions and redshifts for them all. The sources will then be classified according the their properties; whether they are quasars (high or low polarization quasars, BL Lac objects, GPS sources, etc.), radio galaxies, or something else. Finding altogether new and exciting sources is possible!
Click figure to see a larger version
The spectra of quasar 3C 279 from radio to gamma-ray
Figure: D.L. Bertsch (NASA/GSFC)

A lot of preparatory work is needed for a successful satellite mission. We are currently observing sources for the Planck pre-launch catalog at observatories all over the world and also with other satellites (for more information on our observation programmes, go to Observations of active galactic nuclei for Planck Pre-launch Catalog). Our group is using the Metsähovi radio antenna as well as participating in international efforts. We also need to develop methods for extracting point sources from the satellite data stream, and for straightforward portrayal of the differant source classes and their variability. Besides this, we will also be helping the cosmologists to clean the CMB maps effectively and to get more precise results!

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