"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...
