The Planck satellite will measure the cosmic microwave background (CMB) radiation of the entire sky in order to reveal the ultimate secrets of our Universe. Apart from that, it will measure all other radio sources in the sky, including active galactic nuclei (AGNs). The satellite launch is scheduled for 2007 but scientific preparations are already under way in various forms. Researchers from Metsähovi are working on Planck core science program proposals as well as the preparatory science behind them, both theoretical and observational. Lots of prelaunch information on AGNs is required to ensure good-quality CMB maps for cosmologists, and observations for this purpose have been planned and executed.
Year 2000 brought along active and enthusiastic preparation of the Planck core science program. It was decided in the LFI Consortium meeting in Saariselkä, Finland, in February that the second Consortium meeting of the year, held in Manchester, UK, in October would be dedicated to science. It was essential to configure the core science program well in advance of the First General Planck meeting at ESTEC, scheduled for early 2001, which would review the science efforts of both LFI and HFI. In Saariselkä teams were assembled for each science area to ensure that all topics and details would be included and properly considered.
The team concerned with extragalactic radio sources was further divided into eight specific science areas. Metsähovi was a member of five of these areas, and leading two (Variability, BL Lacs and flat-spectrum quasars). The leaders of each science area collected ideas from the entire extragalactic radio source team and submitted ``proto-proposals'', based on the ideas, to the team leaders. A. Lähteenmäki was requested to review the proposals concerning blazars, BL Lac and QSO science in the LFI Consortium meeting in Manchester. Based on the discussions and reviews in Manchester, the number of actual core science abstracts of the extragalactic point source team for the ESTEC meeting was reduced to four (Phenomenology of radio sources, Extreme GPS and other strongly inverted-spectrum radio sources, Astrophysics of quasars and BL Lac objects, Statistical properties). A. Lähteenmäki was chosen to prepare the Astrophysics of quasars and BL Lac objects abstract. A significant contribution aiding the preparation of the three other abstracts was also given. All abstracts were eventually submitted to Planck LFI PI, and would be presented at the ESTEC General Planck meeting in 2001.
The Astrophysics of quasars and BL Lac objects abstract included 6 separate areas of interest: physical models (to study the structure and physics of radio sources, unifying models etc.), BL Lac objects (see ``Radio properties of BL Lacertae objects'' in 2.3.2), fainter flat-spectrum active galactic nuclei (see ``High-frequency radio observations of fainter southern sources'' in 2.3.2), variability (to study the variability phenomenon of AGNs at different scales), follow-up satellite and ground based observations (to supplement Planck observations during and after the mission), and quicklook (to get real-time AGN data from Planck).
Encouraged by the strong Finnish science involvement in Planck (cosmology and foreground science), an application for funding from the Academy of Finland and National Technology Agency research programme for space research (ANTARES) was submitted, in collaboration with teams from Millilab, University of Helsinki and University of Turku. The projects selected for funding will be announced in spring 2001.
