VLBA12B-247

RadioAstron-HSA Observations of Nearby Pulsars

Abstract

We propose observations of nearby pulsars on the longest VLBI baselines yet attained, up to 300,000 km. Our goal is to determine the distance and anisotropy of the material responsible for scattering these pulsars. The material is located preferentially close to the Earth, ~10-100 pc. It is also responsible for scattering extragalactic intra-day variable sources. The ~0.15 mas angular broadening associated with this scattering is too small to measure from Earth, but is accessible to VLBI using RadioAstron and large Earth-based antennas. Comparison of angular broadening with scintillation bandwidth will yield the characteristic distance of the scattering material. We request observations using the High Sensitivity Array (Green Bank Telescope, Arecibo, and Bonn), to observe in concert with the RadioAstron Spacecraft, for diversity of baselines on Earth and to space. We request 24 hours of observing time, at 92 cm observing wavelength. This proposal is submitted as part of the RadioAstron Early Science Program.

Investigators

Name	Institution
Carl Gwinn	California at Santa Barbara, University of
Adam Deller	Swinburne University of Technology
Sarah Buchner	Hartebeesthoek Radio Astronomy Observatory
Michael Johnson	California at Santa Barbara, University of; Center for Astrophysics | Harvard & Smithsonian
Tatiana Smirnova	Lebedev Physical Institute
Yashwant Gupta	Tata Institute of Fundamental Research
Michael Kramer	Manchester, University of; Max-Planck-Institut für Radioastronomie
Yuri Kovalev	Max-Planck-Institut für Radioastronomie
Michael Bietenholz	York University; Hartebeesthoek Radio Astronomy Observatory
Mikhil Popov *	Lebedev Physical Institute
Norbert Bartel	York University

* indicates the PI