15 May 2023
The GASTON (GAlileo Survey of Transient Objects Network) project is based on a 3-months measurements campaign carried out in early 2021 where precise satellite clock measurements are supplemented by an intensive SLR (Satellite Laser Ranging) campaign on Galileo satellites, thanks to the ILRS (International Laser Ranging Service) network, and coordinated by Geoazur laboratory from Cote d’Azur observatory.
The Galileo constellation is well-suited to search for dark matter (DM) transients because of the extremely stable passive H-maser clocks onboard satellites, because of the corner cubes allowing to perform SLR measurements and because of the number of satellites and of their spatial distribution, allowing to exhibit distant correlations with the delay predicted by the trajectory of our Solar System within the DM halo. Another strong point of the GASTON project is the better modeling of the transient signal since we have considered a smooth profile for the DM transient (instead of a step function) derived from a specific Lagrangian formulation. In addition, we also consider for the first time the orbital motion of the satellites. This enables to extend the potential detection to any large DM objects, well beyond the size of the Earth, namely a strong improvement of the current literature dealing with the GPS constellation.
The GASTON project can be divided into two levels. First, the exclusion level which consists in excluding large regions of the parameter space by producing a first rough analysis. Besides the notable scientific interest of such exclusion, it offers the advantage to target the region of the parameter space where to seek a possible signature of DM transients. Then, the second level, that we call the “detection level” deals with an exhaustive correlation analysis over the whole set of available Galileo satellites. The purpose of this second step is the direct detection of possible signatures of variation of fundamental constants or the derivation of a refined exclusion zone.
Publications
- Bertrand, B., P. Defraigne, A. Sheremet, A. Hees, P. Wolf, P. Delva, and others, ‘GASTON Project: Searching Dark Matter Using the Galileo Satellites’, in Proceedings of the ETFS/IFCS 2021, 2021