MAGE Mid-term review (23/09/04): network report * Financial support provided through the European Community's Improving Human Potential Program under contract RTN2-2002-00217, MAGE MAGE Mid-term review (23/09/04): network report S. Pireaux

MAGE factual information: Name: Sophie PIREAUX Nationality: Belgian Age at appointment: 28 Start of appointment: 1st January 2003 End of appointment: 31st December 2004 Category: post-doc Specialty: - relativistic gravitation - IAU recommendations (relativistic ref. systems, space-time transfo, metric) - PPN formalism for testing alternative theories of gravitation - satellites and laser ranging tests of relativity Place of work: UMR5562 Dynamique Terrestre et Planétaire (DTP) Groupe de Recherche en Géodésie Spatiale (GRGS) Observatoire Midi-Pyrénées, Toulouse Country of work: France Previous experience in network: none

Sketches of the young researcher: A/ Scientific background: Sept 02-Sept 98: PhD, research assistant, doctoral school, FYMA, UCL (Belgium) Thesis: “Light deflection experiments as a test of relativistic theories of gravitation.” Advisor: JM. Gérard Contract: UCL researcher on exterior funds (IISN, convention n°4.4509.86.051) 15 Nov 02 – 31 Dec 02: Assistant INSU/CNRS, DTP, OMP (France) Jan 03 – Dec 04: present MAGE post-doc B/ Future: Jan 2005- Dec 2006 (or 2007?): CNES Post-doc, UMR GEMINI, OCA (France) Subject: ``Solar astrodynamics and relativistic spin-orbit coupling'', Collaboration: JP. Rozelot, E. Bois …: apply to CNRS/CNAP, UMR ARTEMIS, OCA Subject: ``Tensor Scalar signatures in gravitational wave emission and detection with LISA?'' Collaboration: with B. Chauvineau.

C/ Comments on present post-doctoral position: Mobility: contacts with geodesy community: their needs relativistic gravitation? a synergy gravitational theoreticians geodesists is crucial! contacts with previous institute: regular home missions Advantages: Interesting research project: good prospects native relativistic approach ultimately needed Drawbacks: Ambitious project: single person, 2-year post-doc Presently no joined effort …but GRGS expressed interest at GRGS Summer School 2004 ???

Royal Observatory of Belgium MAGE research subject: « Integrating the motion of satellites in a consistent relativistic framework » (Semi-Classical) Relativistic Motion Integrator Observatoire Midi-Pyrénées Royal Observatory of Belgium JP. Barriot P. Rosenblatt Collaborators:

Achievements: basis of RMI software First post-doctoral year: Study of IAU2000 conventions for astronomy / space-astrometry Comparison of different relativistic time transfo TT-DTB: SOFA libraries (IAU 2003), DE405 Time-Ephemeris (Irwin and Fukushima, 1999) Implement transfo between different time scales: TAI , TT, t, TDB, TCB, TCG Basis of native relativistic software: implementation for simple metrics (Schwarzschild, Kerr, mono / multi-pole) Started implementation of GCRS metric recommended by the IAU2000 resolutions Started implementation of new NRO model for Earth rotation (IAU2000) IAU = International Astronomical Union TDB = Dynamic Barycentric Time scale used in the JPL ephemerides TAI = International Atomic Time TT= Terrestrial Time t = Proper time TCB = Barycentric Coordinate Time TCG = Geocentric Coordinate Time GCRS = Geocentric Coordinate Reference System NRO = Non Rotating Origin RMI =Relativistic Motion Integrator 2nd post-doctoral year How non-gravitational forces fit in the relativistic framework How relativistic equations with non-gravitational forces reduce to the classical ones Order of magnitude of relativistic corrections

Projects for the near future: develop RMI software What still needs to be done: Continue implementation of IAU 2000 GCRS metric Continue implementation of coordinate transfo Verify internal / external coherence of ephemeris, astronomical constants used Make actual comparisons with pre-existing classical orbitography softwares Symplectic numerical integrator to conserve norm of quadrivector propre velocity Transpose results to the case of a probe orbiting Mars Contact Sophie.Pireaux@cnes.fr