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 |
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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