2021MNRAS.506.5160M -
Mon. Not. R. Astron. Soc., 506, 5160-5169 (2021/October-1)
Scintillation of PSR B1508+55 - the view from a 10 000-km baseline.
MARTHI V.R., SIMARD D., MAIN R.A., PEN U.-L., VAN KERKWIJK M.H., VANDERLINDE K., GUPTA Y., ROBERTS C. and QUINE B.M.
Abstract (from CDS):
We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550-750 MHz of the scintillation of PSR B1508+55, resulting in an ∼10 000-km baseline. This regime of measurement lies between the shorter few 100- to 1000-km baselines of earlier multistation observations and the much longer earth-space baselines. We measure a scintillation cross-correlation coefficient of 0.22, offset from zero time lag due to a ∼45-s traversal time of the scintillation pattern. The scintillation time of 135 s is 3x longer, ruling out isotropic as well as strictly one-dimensional scattering. Hence, the low cross-correlation coefficient is indicative of highly anisotropic but two-dimensional scattering. The common scintillation detected on the baseline is confined to low delays of <=1µs, suggesting that this correlation may not be associated with the parabolic scintillation arc detected at the GMRT. Detection of pulsed echoes and their direct imaging with the Low-Frequency Array (LOFAR) by a different group enable them to measure a distance of 125 pc to the screen causing these echoes. These previous measurements, alongside our observations, lead us to propose that there are at least two scattering screens: the closer 125-pc screen causing the scintillation arc detected at GMRT, and a screen further beyond causing the scintillation detected on the GMRT-ARO baseline. We advance the hypothesis that the 125-pc screen partially resolves the speckle images on the screen beyond leading to loss of coherence in the scintillation dynamic spectrum to explain the low cross-correlation coefficient.
Abstract Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
scattering - methods: observational - techniques: interferometric - pulsars: B1508+55 - radio continuum: ISM
Simbad objects:
3
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2021MNRAS.506.5160M and select 'bookmark this link' or equivalent in the popup menu