PSRPI is a project to map the Galactic distribution of radio pulsars, using Very Long Baseline Interferometry (VLBI). The VLBA can measure the parallax and proper motion of pulsars as faint as approximately 1 mJy to a typical accuracy of around 40 microarcseconds and 40 microarcseconds/year respectively. This is sufficient to calculate the distance and velocity of a source at 4 kpc - halfway to the Galactic center - to an accuracy of around 15%.
The key goals of the PSRPI project are:
1) to obtain accurately calibrated luminosities and distances for a large number of pulsars, and determine the magnitude of the effect that distance errors have had on previous estimations of the pulsar distance and luminosity functions;
2) to greatly improve the Galactic electron density distribution models used to estimate distances to other pulsars from their dispersio n measures;
3) to make associations between pulsars and supernova remnants;
4) to improve reference frame ties between the ICRF, optical and solar system barycenter frames.
The first phase of the PSRPI program, targeting 60 widely separated pulsars to focus on improving the Galactic electron density distribution model, completed observing in December 2013. Information on these 60 pulsars can be found on the Project Status page, while the results are available from the Data release page (links in the right sidebar). A number of publications are currently in preparation / have been published (see Publications link on right).
The next phase of the PSRPI project - MSPSRPI - was undertaken from 2015 - 2018. This phase targets millisecond pulsars exclusively, and is focused on improving the timing models of pulsars used for gravitational wave detection and GR tests, as well as significantly improving the frame tie between the optical, radio and timing frames. Information on the 42 pulsars targeted for this phase of the project is also available in the Project Status page (link on right).
To obtain our quality astrometric results, we observe 8 epochs on each source with the VLBA. Each source has an associated in-beam calibrator to reduce the systematic error contributions of the ionosphere. These in beam sources are located using an efficient multiple field search with the DiFX software correlator of the VLBA. More details are available in the publications listed on the Publications page (link on right).