ROADMAP FOR THE INAF PARTICIPATION IN LOW FREQUENCY ARRAY (LOFAR)
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The race towards SKA has generated a set of precursors/pathfinders that today and for a decade will lead the frontier research in radio astronomy. Not taking part in any of these precursors/pathfinders, Italy would preclude a participation with the due critical mass to the multitude of scientific developments and technical innovations in continuous evolution preparing the way for scientific exploration with SKA.
LOFAR is the largest precursor of SKA in terms of effective area and generated data rates. It is a revolutionary aperture array that extends across Europe and is starting to open a new observational window at low radio frequencies, promising fundamental steps forward in a multitude of astrophysics and cosmology areas.
At the moment the research groups belonging to LOFAR are structured in 6 Key Projects (KP) within which much of the technical and scientific know-how is developed. They cover numerous research areas to which INAF community is strongly interested. The Italian participation in LOFAR has been a goal pursued by INAF community for several years but which has been realized only recently thanks to an INAF top management initiative to ensure INAF participation in a SKA science ready pathfinder, funded on SKA funds Industry.
In June 2017 INAF started a negotiation with the International LOFAR Telescope (ILT) and ASTRON in order to join the LOFAR project with the immediate inclusion of the research staff into the KP.
The negotiation ended with a proposal for a roadmap that would guarantee INAF the role of ILT Full Member FROM THE EARLY, including the KPs access and a yearly based reserved slice of observation time. In a first phase this role would be guaranteed by the INAF technological involvement in the upgrade envisaged for LOFAR (LOFAR 2.0), and at a later stage (presumably from 2021-22) by the acquisition of a LOFAR 2.0 station.
In particular, the scheme envisaged by the roadmap is the following:
1. INAF will lead an Italian consortium for LOFAR (LOFAR IT) of which it will be the legal representative in relations with ILT. The first step foresees a consortium between INAF and the Physics Department of the Turin University(UniTo);
2. INAF will sign an agreement with AstroTec with which it undertakes to acquire a LOFAR 2.0 Station to be installed in Medicina (Bo) by 2021-22;
3. INAF will adhere to a technological collaboration agreement 2018-2021 with ASTRON for the development of LOFAR 2.0;
4. LOFAR IT (INAF) will undertake to pay the annual fee for the ILT consortium.
The cost of this operation for INAF can be estimated at a maximum of 2.4 MEuro over 5 years, based on the conditions agreed with the partners (ILT, ASTRON, AstroTec) and regardless of the details of the LOFAR IT consortium (TAB 1, SEZ 5).
This investment should be enhanced by creating the optimal conditions for data access and analysis in order to optimize the scientific impact for INAF community. The LOFAR data analysis requires very complex computational procedures and infrastructures suited to the size of the datasets produced by the individual observations, typically 10-20 TB. As demonstrated in this study, at the moment INAF does not own/have access to such infrastructures. For this reason we have also assessed sustainable measures to complement the investment mentioned above to finance proximity calculation resources for the LOFAR data analysis that meets the requirements. In this case the total cost of the LOFAR operation for INAF can be estimated between 2.55 and 2.95 MEuro in 5 years, depending on whether an investment is also foreseen for scientific staff, and net of already existing external co-financing funds and the contribution coming from the UniTo partner (TAB 2, SEZ 5). This cost could be reduced enlarging the LOFAR IT consortium to other universities and thanks to possibly available additional co-financing external funds.