HR: 0800h
AN: G31B-0795    [Abstracts]
TI: Use of Pulsar Timing at Nancay 's Radiotelescope for the Construction of the Dynamical Reference Frame
AU: * Souchay, J
EM: Jean.Souchay@obspm.fr
AF: Observatoire de Paris, 61, avenue de l'observatoire, Paris, 75014 France
AU: Cognard, I
EM: icognard@cnrs-orleans.fr
AF: LPCE/CNRS Orleans, 3A, Avenue de la Recherche Scientifique, Orleans, Cx 2,45071 France
AB: Pulsars, discovered by radioastronomers in 1967, not only offer the opportunity to study fundamental physics in conditions not reachable on Earth, but also can play an essential role in modern astrometry. Indeed, pulsar timing analysis is directly dependent on the way by which the position of the earth on its orbit is modelized. Indeed, the arrival times of the pulses are shifted by the Doppler effect due to the relative speed of the Earth on its orbit, whose direction and amplitude vary along the year with respect to the line of sight. Therefore, it provides precious information about the location of the ecliptic, i.e. a dynamical frame related to the revolution of the Earth., with respect to a frame related to the pulsars, as galactic objects. Thus we explain how radio pulses observations of pulsars carried out at Nan‡ay's radiotelescope can participate actively to the construction of both a very accurate catalogue of the coordinates of pulsars, which should give birth to a pulsar Reference Frame, and to a very accurate positioning of the ecliptic with respect to inertial directions. A set of about 20 pulsars are regularly observed at Nan‡ay, among which PSR1937+21 and PSR 1821-21 have been subject to a very intensive campaign for 15 years. We show the advantage of all these observations to accomplish the objectives above.
DE: 2194 Instruments and techniques
DE: 1247 Terrestrial reference systems
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting