Correlating EVN data at JIVE
The Joint Institute for VLBI ERIC (JIVE) is a research infrastructure providing central support to the EVN. JIVE's mission is to promote and implement the use of Very Long Baseline Interferometry (VLBI) and other radio astronomical techniques. JIVE implements the core data processing and user services that turn the EVN network of distributed telescopes around the world into a single observatory to study the radio sky at the highest possible resolution.
The SFXC software correlator
The EVN data processor at JIVE is a software FX-kind correlator (SFXC). SFXC was installed in February/March 2010 and has taken over all correlation in December 2012. The original cluster has been extended several times and currently handles approximately 20 stations at 2Gbit/s in real-time e-VLBI mode and many more for traditional disk-based VLBI. The SFXC software correlator is openly accesible (open source) and distributed under the terms of the General Public License (GPL). For further information about the code and installation, please visit the SFXC JIVE Wiki. We kindly request users of SFXC to reference the paper that describes its algorithm and implementation (Keimpema et al. 2015).
Among other capabilities, the EVN SFXC software correlator at JIVE allows the different correlation modes:
- Pulsar gating and binning.
- More than 2048 spectral channels across each subband/polarization.
- Multiple correlation phase-centers within the primary beam of the telescopes.
By default, all EVN observations are correlated with SFXC at JIVE, and the data can be downloaded from the EVN Data Archive (for further information on the processing performed at JIVE for EVN data from the correlation to the distribution stage, please consult the EVN Data Access page). It is also possible to submit a proposal just for the use of the EVN correlator. Global VLBI projects can be processed either by the EVN correlator at JIVE or the VLBA DiFX correlator at NRAO. A specific correlator may be requested for technical reasons, which should be explained in the proposal.
Alternative correlations at MPIfR (Bonn, Germany)
Limited time may be available for the correlation of EVN experiments on the Bonn DiFX Correlator, but only by arrangement with MPIfR correlator staff prior to proposal submission. Suitable projects will be those for which the scientific advantage of using the MPIfR Correlator is given in the proposal, or those which include an MPIfR collaborator who wishes to have a closer “hands-on” approach to the data flow.