Wide-band Simultaneous Observations of Pulsars: Disentangling Dispersion Measure and Profile Variations
Abstract
Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous observations of four pulsars with LOFAR (at 40-190 MHz), the 76-m Lovell Telescope (at 1400 MHz) and the Effelsberg 100-m Telescope (at 8000 MHz) to test the accuracy of the dispersion law over a broad frequency range. In this paper we present the results of these observations which show that the dispersion law is accurate to better than 1 part in 100000 across our observing band. We use this fact to constrain some of the properties of the ISM along the line-of-sight and use the lack of any aberration or retardation effects to determine upper limits on emission heights in the pulsar magnetosphere. We also discuss the effect of pulse profile evolution on our observations, and the implications that it could have for precision pulsar timing projects such as the detection of gravitational waves with pulsar timing arrays.
Keywords
Cite
@article{arxiv.1204.3864,
title = {Wide-band Simultaneous Observations of Pulsars: Disentangling Dispersion Measure and Profile Variations},
author = {T. E. Hassall and B. W. Stappers and J. W. T. Hessels and M. Kramer and A. Alexov and K. Anderson and T. Coenen and A. Karastergiou and E. F. Keane and V. I. Kondratiev and K. Lazaridis and J. van Leeuwen and A. Noutsos and M. Serylak and C. Sobey and J. P. W. Verbiest and P. Weltevrede and K. Zagkouris and R. Fender and R. A. M. J. Wijers and L. Bahren and M. E. Bell and J. W. Broderick and S. Corbel and E. J. Daw and V. S. Dhillon and J. Eisloffel and H. Falcke and J. -M. Griessmeier and P. Jonker and C. Law and S. Markoff and J. C. A. Miller-Jones and R. Osten and E. Rol and A. M. M. Scaife and B. Scheers and P. Schellart and H. Spreeuw and J. Swinbank and S. ter Veen and M. W. Wise and R. Wijnands and O. Wucknitz and P. Zarka and A. Asgekar and M. R. Bell and M. J. Bentum and G. Bernardi and P. Best and A. Bonafede and A. J. Boonstra and M. Brentjens and W. N. Brouw and M. Bruggen and H. R. Butcher and B. Ciardi and M. A. Garrett and M. Gerbers and A. W. Gunst and M. P. van Haarlem and G. Heald and M. Hoeft and H. Holties and A. de Jong and L. V. E. Koopmans and M. Kuniyoshi and G. Kuper and G. M. Loose and P. Maat and J. Masters and J. P. McKean and H. Meulman and M. Mevius and H. Munk and J. E. Noordam and E. Orru and H. Paas and M. Pandey-Pommier and V. N. Pandey and R. Pizzo and A. Polatidis and W. Reich and H. Rottgering and J. Sluman and M. Steinmetz and C. G. M. Sterks and M. Tagger and Y. Tang and C. Tasse and R. Vermeulen and R. J. van Weeren and S. J. Wijnholds and S. Yatawatta},
journal= {arXiv preprint arXiv:1204.3864},
year = {2012}
}
Comments
20 Pages, 14 Figures, Accepted for publication in Astronomy & Astrophysics