Astronomy

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Astron

Initiator: ASTRON Netherlands Institute for Radio Astronomy

eu  SNN

This project was co-financed by the EU, the European Fund for Regional Development and the Northern Netherlands Provinces (SNN), and EZ/KOMPAS.

Software Project Plan and Organization

Software

Successful low frequency observations largely depend on the availability of new digital backends with numerous narrow-frequency channels to cope with man-made interference signals and to avoid depolarisation by Faraday rotation across the observing band. Multi-channel polarisation data (spectro-polarimetry) are used for the technique of Rotation Measure (RM) Synthesis. This method has first been successfully applied on data taken with the Westerbork Synthesis Radio Telescope (WSRT) and is presently further developed by the project team. The multi-channel polarisation data are Fourier-transformed into a data cube With Faraday depth as the third coordinate. The Faraday depth (FD) is the integral of the plasma density times the regular field strength along the line of sight.

RM Synthesis with LOFAR takes advantage of the broad frequency coverage achievable with this new-technology telescope. LOFAR observations with large signal-to-noise in the higher band (120-240 MHz) will allow the detection of FD values with precisions below 1 rad/m^2.  This is sufficient to detect magnetic fields below 1 μG (0.1 nT), which was never possible before. In the LOFAR lowband range (30-80 MHz), the FD accuracy is formally even better, but the calibration is more difficult and the sensitivity of the antennae is lower than in the highband range.

Project Team

The project presently consist of 18 full members from 4 countries, who agreed to invest a significant fraction of their time for the project, plus another 30 associated members from 8 countries. The project is led by a German/Dutch/UK management team. The principle investigator is Rainer Beck (Max Planck Institute for Radio Astronomy, Bonn).

ASTRON initiated LOFAR as a new and innovative effort to force a breakthrough in sensitivity for astronomical observations at radio-frequencies below 250 MHz. 
Development: Dripl | Design: Kuenst   © copyright 2014 Lofar