Asteroids, Comets, Meteors and Ephemerides (ACME)
ACME, through the works of its members, has already acquired a leading experience and expertise related to the small bodies of the Solar system. This excellence is worth as much on the observations – base of any study in astronomy –, of their treatment, of their modeling as of their interpretation. ACME has in particular its own observation devices already tested (T1M Pic du Midi and T60 Makes on the island of La Réunion). But they also use a wide range of observations from stellar occultation – essential to the knowledge of shapes and sizes – to adaptive optics via spectroscopy and photometry. The precise interaction of all these methods and techniques is the first requirement of the team.
More
Astronomy and Dynamical Systems (ASD)
The multidisciplinary team Astronomy and Dynamical Systems (ASD) has been created in 1992. It brings together theoricians of the dynamical systems and experts in celestial mechanics.
More
Optical frequency metrology (FOP)
The Optical Frequency Metrology team designs and builds atomic clocks for a variety of applications. As predicted by Einstein as early as 1907, time is coupled to gravitational potential: this is the so-called gravitational time dilation effect. For an atomic clock, this translates into a coupling between frequency and the geopotential felt locally by the atoms.
More
History of astronomy
Current research by members of the team involves a study of astronomical science practices from the Middle Ages to the 20th century. Astronomical observations, mathematics, physics, celestial mechanics, geodesy, cartography, cosmology, atmospheric phenomena, meteorology, instruments, cultural contexts and places of production of this knowledge interact and make up the field covered by this science, whose evolutions can only be understood over the long term.
More
Atom Interferometry and Inertial Sensors (IACI)
The “Atomic Interferometry and Inertial Sensors” team studies the possibilities offered by atomic interferometry for high-precision measurements, and in particular for the realization of very high-performance inertial sensors. It is a pioneer in the development of these sensors, and has internationally recognized expertise, particularly in the metrological study of instruments.
More
Planetology and Environments from Ground Astrometry and Space Exploration (PEGASE)
The PEGASE team is composed of astronomers, professors, PhD students and postdoctorates working on the problematics related to the dynamics of the solar system objects, from the terrestrial environment to the Trans-Neptunian objects. PEGASE brings together astronomical observers, celestial mechanics theorists and specialists in numerical modeling, experts in the dynamics of natural satellites, artificial satellites, space debris, asteroids, meteors and planet formation.
More
Earth Rotation and Space Geodesy (REFAG)
The main scientific thrusts of the Référentiels astrogéodésiques (REFAG) team are as follows:
- definition and production of global reference frames with millimetric accuracy (0.1 mas), including the extragalactic celestial reference frame using VLBI measurements, determination of the Earth’s rotation using VLBI, GNSS, laser satellite telemetry and DORIS measurements, sea levels using radar altimetry and in situ measurements, and the earth-moon distance using laser-moon telemetry,
- the study of the links between the Earth’s rotation, internal dynamics (deformations, tectonics, seismicity, volcanism) and external dynamics (atmosphere, oceans, continental waters) and astronomical forcing from the hour to the century,
- the study of the links between astrometry, photometry and the multi-wavelength emission mechanisms of the AGN population making up celestial references.
More
Microwave references and time scales (REFMET)
This team merges the related activities of microwave frequency metrology and time metrology. It is responsible for two historical missions:
- generate, maintain and disseminate a primary frequency reference to contribute to the definition of the international system (SI) second and the accuracy of international atomic time (TAI, UTC).
- generate the reference time scale for France, UTC(OP), the French prediction of UTC, which is the basis of legal time, connect it at national and international level and ensure its distribution (general public, industry, military), a mission carried out within the Service des références nationales de temps (RNT).
More
Theory and Metrology
Theory and Metrology team specializes in relativistic modeling of metrological data, in particular with a view to testing the fundamental laws of physical theories. It has carried out several state-of-the-art tests of the equivalence principle. While a pillar of modern classical theories, this principle is broken in a large number of theoretical models for the unification of fundamental interactions, dark matter and dark energy. Developing experiments to confront this principle at ever-smaller levels can therefore lead to the discovery of new physics.
More
