Interferometric study of PSR B0329+54 and the interstellar medium, at 324 MHz, with maximum baselines near 1 light second

With many thanks, I refer to:

"PSR B0329+54: Substructure in the scatter-broadened image discovered with RadioAstron on baselines of up to 235,000 km"
   
Popov, M. V.; Andrianov, A. S.; Bartel, N.; Gwinn, C. R.; Johnson, M. D.; Joshi, B. C.; Kardashev, N. S.; Karuppusamy, R.; Kovalev, Y. Y.; Kramer, M.; Rudnitskii, A. G.; Safutdinov, E. R.; Shishov, V. I.; Smirnova, T. V.; Soglasnov, V. A.; Zensus, J. A.; Zhuravlev, V. I.

http://arxiv.org/abs/1501.04449

25 references at:
http://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2015arXiv150104449P&refs=REFERENCES&db_key=PRE

Abstract: "We studied scattering properties of the pulsar PSR B0329+54 with a ground-space radio interferometer RadioAstron which included the 10-m Space Radio Telescope, the 110-m Green Bank Telescope, the 14x25-m Westerbork Synthesis Radio Telescope, and the 64-m Kalyazin Radio Telescope. The observations were performed at 324 MHz on baselines of up to 235,000 km in November 2012 and January 2014. At short ground-space baselines of less than about 20,000 km, the visibility amplitude decreases with the projected baseline length, providing a direct measurement of the diameter of the scattering disk of 4.7±0.9 mas. The size of the diffraction spot near Earth is 15,000±3,000 km. At longer baselines of up to 235,000 km, where no interferometric detection of the scattering disk would be expected, significant visibilities were observed with amplitudes scattered around a constant value. These detections result in a discovery of a substructure in the completely resolved scatter-broadened image of the pointlike source, PSR B0329+54. They fully attribute to properties of the interstellar medium. The visibility function at the longest ground-space baselines in the delay domain consists of many isolated unresolved spikes, in agreement with the amplitude-modulated noise model. Within the assumption of turbulent as well as large-scale irregularities in the plasma of the interstellar medium, we estimate that the effective scattering screen lies 0.35±0.10 of the distance from Earth toward the pulsar."

More on RadioAstron at:

http://herrero-radio-astronomy.blogspot.com/2013/07/the-radioastron-1-light-second-baseline.html

http://herrero-radio-astronomy.blogspot.com/2011/07/10-meter-radioastron-russian-space.html

http://www.asc.rssi.ru/radioastron/

Publications of RadioAstron :
http://www.asc.rssi.ru/radioastron/publications/publ.html

Wikipedia article:
https://en.wikipedia.org/wiki/Spektr-R

"...Spektr-R[2] (or RadioAstron) is a Russian scientific satellite with a 10 m (33 ft) radio telescope on board. It was launched on 18 July 2011,[3] by Zenit-3F launcher, from Baikonur Cosmodrome to perform research on the structure and dynamics of radio sources within and beyond our galaxy. Together with some of the largest ground-based radio telescopes, this telescope forms interferometric baselines extending up to 350,000 km (220,000 mi)..."

...o...

The RADIOASTRON 1 light second baseline Russian interferometer

I refer to Kardashev at al. 2013:
http://arxiv.org/abs/1303.5013
http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1303.5013
and my post:
http://herrero-radio-astronomy.blogspot.com/2011/07/10-meter-radioastron-russian-space.html

The Russian Academy of Sciences and Federal Space Agency, together with the participation of many international organizations, worked toward the launch of the RadioAstron orbiting space observatory with its onboard 10-m reflector radio telescope from the Baikonur cosmodrome on July 18, 2011. Together with some of the largest ground-based radio telescopes and a set of stations for tracking, collecting, and reducing the data obtained, this space radio telescope forms a multi-antenna ground-space radio interferometer with extremely long baselines, making it possible for the first time to study various objects in the Universe with angular resolutions a million times better than is possible with the human eye. The project is targeted at systematic studies of compact radio-emitting sources and their dynamics. Objects to be studied include supermassive black holes, accretion disks, and relativistic jets in active galactic nuclei, stellar-mass black holes, neutron stars and hypothetical quark stars, regions of formation of stars and planetary systems in our and other galaxies, interplanetary and interstellar plasma, and the gravitational field of the Earth. The results of ground-based and inflight tests of the space radio telescope carried out in both autonomous and ground-space interferometric regimes are reported. The derived characteristics are in agreement with the main requirements of the project. The astrophysical science program has begun.

10 meter RadioAstron Russian space radiotelescope is in orbit

The Spectrum-R space observatory was launched from the Baikonur Cosmodrome on 110718:
http://www.federalspace.ru/main.php?id=2&nid=12007

The telescope dish is made from 27 carbon fiber petals. It will operate as an interferometer together with ground antennas.

RadioAstron home page:
http://www.asc.rssi.ru/radioastron/

Russian Federal Space Agency:
http://www.federalspace.ru/main.php?lang=en