One research axis developed within our lab is devoted to the modeling of light propagation in metric theory of gravitation. In that particular context, researchers at SYRTE have developed a new and very efficient method to compute the propagation of light within curved space-time. This method is based on a solution of the eikonal equation of the time transfer and is known as the “Time Transfer Functions” formalism. The theoretical developments of this method can be found in [1,2,3], applications for space missions can be found in [4,5,6] and astrometric applications can be found in [7,8,9]. Note that this method has recently been implemented within the Gaia software [8]. Theoretical researches around the relativistic modeling of light propagation are still on-going.

On a more practical level, our team contributes to the implementation of software to analyze observations. For example, we are involved in the development of the Gaia software, in the development of the software used to analyze observations of short period stars that are orbiting the supermassive black hole at the center of our Galaxy, in the development of the software to analyze Lunar Laser Ranging observations, Very Long Baseline Interferometry (VLBI), etc…

[1] C. Le Poncin-Lafitte, B. Linet, P. Teyssandier, Classical and Quantum Gravity 21, 4463, 2004. http://dx.doi.org/10.1088/0264-9381/21/18/012
[2] P. Teyssandier, C. Le Poncin-Lafitte, Classical and Quantum Gravity 25, 145020, 2008. http://dx.doi.org/10.1088/0264-9381/25/14/145020
[3] B. Linet, P. Teyssandier, Classical and Quantum Gravity 30, 175008, 2013, http://dx.doi.org/10.1088/0264-9381/30/17/175008
[4] A. Hees, B. Lamine, et al, Classical and Quantum Gravity 29, 235027, 2012. http://dx.doi.org/10.1088/0264-9381/29/23/235027
[5] A. Hees, S. Bertone, C. Le Poncin-Lafitte, Phys. Rev. D 89, 064045, 2014. http://dx.doi.org/10.1103/PhysRevD.89.064045
[6] A. Hees, S. Bertone, C. Le Poncin-Lafitte, Phys. Rev. D 90, 084020, 2014. http://dx.doi.org/10.1103/PhysRevD.90.084020
[7] S. Bertone, O. Minazzoli, et al, Classical and Quantum Gravity 31, 015021, 2014. http://dx.doi.org/10.1088/0264-9381/31/1/015021
[8] S. Bertone, A. Vecchiato, et al, Astronomy & Astrophysics 608, A83, 2017. http://www.aanda.org/10.1051/0004-6361/201731654