"Radio interferometry at the edge of the Universe and in the Solar System"
L.I. Gurvits (Joint Institute for VLBI in Europe Dwingeloo, The Netherlands)
Abstract:
Radio inteferometry made a spectacular progress over the last decades. This is particularly visible in the developments of its ultimate case, the Very Long Baseline Interferometry (VLBI) technique. Proposed in the USSR in the beginning of 1960s, this technique occupies a very special place among the variety of the astronomical tools as the one providing the sharpest view at the Universe.
I will briefly review the current status of the technique using as an example the most sensitive VLBI facility – the European VLBI Network. Its current specification includes such technical characteristics as 1 Gbit/s recording per telescope, disk-based operations and real-time processing capabilities. These technological advances made possible several recent state-of-the-art scientific applications of which two will be reviewed in details:
1). Over the last years VLBI surveys of extragalactic sources reached millijansky-level flux densities enabling statistical studies of thousands of sources. Such the surveys focus on astrophysical properties of AGN as the most powerful “engines” of the Universe as well as utilization of AGN’s as cosmological probes. I will present results of recent VLBI studies of mJy-level quasars, including the most distant radio-loud quasar at z=5.772.
2). On 14 January 2005, the ESA-led mission Huygens entered the atmosphere of Titan and after a 2.5-hour parachute glide made a safe touch-down on the surface marking by far the most distant and challenging controlled landing to date. A global network of 17 radio telescopes provided crucial radio astronomy support to the mission, including ultra-precise VLBI tracking of the probe. I will discuss scientific and technological challenges of the radio astronomy segment of the mission and present its preliminary results in concurrence with findings of other components of the Cassini/Huygens mission.