Effelsberg telescope included in a world-wide network

Largest European radio telescope inaugurated as member of e-VLBI

The telescope was connected by a 35km dedicated high-speed fibre data link to Bonn earlier this year, allowing it to participate in electronic, real-time Very Long Baseline Interferometry observations (e-VLBI).

e-VLBI is a technique by which remotely located radio telescopes simultaneously observe the same region of sky, and data from each telescope is sampled and streamed to a central data processor via high-speed communication networks. This processor, a purpose-built supercomputer, decodes, aligns and correlates the data in real-time for every possible telescope combination and can generate images of cosmic radio sources with up to a hundred times better resolution than images from the best optical telescopes.

"The ability to send data electronically and correlate it in real-time allows astronomers to receive their data within hours of conducting an observation, rather than weeks later via the traditional VLBI method of recording data onto disks and shipping it to the correlator," explains Dr. Huib Jan van Langevelde, Director of the Joint Institute for VLBI in Europe (JIVE), which developed and maintains the correlator for the European VLBI Network (EVN). He adds, "If a transient event such as a supernovae or gamma-ray burst is detected, the astronomer can respond quickly with a follow-on 'Target of Opportunity' (ToO) observation." In fact, the observing time reserved for the demonstration during the dedication was assigned at short notice to astronomical observations of a flaring black-hole candidate source.

Wednesday's inauguration marks the connection of the largest and most sensitive single dish in the EVN. The addition of the Effelsberg telescope nearly doubles the sensitivity of the EVN's e-VLBI capabilities, allowing it to detect the faintest cosmological sources. Already since April, the Effelsberg telescope has participated in multiple e-VLBI scientific observations.

"The completion of the high-speed fibre optic link is a remarkable achievement and will enable the EVN to conduct e-VLBI experiments of a wide range of astrophysical objects," says Prof. Dr. J. Anton Zensus, Director at MPIfR. "In particular we hope to be able to study objects that show sudden variation in a faint central region where we suspect the presence of massive block holes."

The inaugural event included comments by Zensus, Langevelde and Mr. Jean-Luc Dorel, Programme Officer with the European Commission's Information Society and Media Directorate General (DG-INFSO). Attendees were also treated to an e-VLBI demonstration featuring the live ToO observation and a tour of the telescope.

About e-VLBI: e-VLBI is a technique by which remotely located radio telescopes observe the same region of sky simultaneously, and data from each telescope are sampled and sent to a central processor via high-speed communication networks operating in real-time. This central data processor, a purpose-built supercomputer, decodes, aligns and correlates the data for every possible telescope combination and can generate images of cosmic radio sources with up to a hundred times better resolution than images from the best optical telescopes. EXPReS is developing e-VLBI to replace traditional VLBI's reliance on storing data on high-capacity disk arrays which are shipped to the correlator. Electronic, real-time VLBI eliminates the shipping of disks and provides astronomers with correlated data in a timely fashion, allowing them to exploit transient astronomical events called Targets of Opportunity.

About EXPReS: Express Production Real-time e-VLBI Service (EXPReS) is a three-year project funded by the European Commission with the objective of creating a distributed, large-scale astronomical instrument of continental and intercontinental dimensions. This electronic Very Long Baseline Interferometer (e-VLBI) is achieved using high-speed communication networks operating in real-time and connecting together some of the largest and most sensitive radio telescopes on the planet. EXPReS is comprised of 19 radio astronomy institutes and national research networks in 14 countries and is coordinated by JIVE, the Joint Institute for VLBI in Europe.