Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères



par Mickaël Coriat - publié le , mis à jour le

SKA through its pathfinders

Credits: SKA Organisation

The international SKA (Square Kilometre Array) project, in which the French community has shown a strong interest, aims to match in resolution and sensitivity the largest ground and space-based observatories, and to cover the 50 MHz to at least 15 GHz range (the objective is to cover frequencies from 50 MHz to 24 GHz). During the first meeting (3-4 February 2021) of the board of SKA Observatory (SKAO), the Inter-Governmental Organisation in charge of building and operating the SKA telescopes, France expressed its wish to become a member of SKAO. SKA1, the first phase of SKA, with its two components SKA1-LOW and SKA1-MID, will be fully operational around 2026 - 2027, but SKA’s precursors and pathfinders [1] are already operational and used, among others, by French scientists. These are in particular the LOFAR network (10 - 240 MHz), inaugurated in 2010, initially Dutch and then opened to European partners including France, and, at a higher frequency (900 - 1670 MHz), MeerKAT in South Africa. With NenuFAR, a 10-year national effort, France has a very large low-frequency radio telescope, which is among the most powerful in the world in its frequency range, between 10 MHz and 85 MHz. NenuFAR is in the Early Science phase and the first Key Programmes, led by teams including French and foreign astronomers, began in July 2019.

Crédits: Christian PENIN - Station de Radioastronomie de Nançay

SKA is an observatory which by its scientific possibilities concerns and interests a large part of the French astronomical community. Radio astronomy nevertheless remains a difficult field, and SKA will be a very powerful but complex observatory to use in some of its observation modes. In addition, the SKA Regional Centers (SRC) will play an essential role in providing access to SKA.

The purpose of the SKATE observation service is to serve the very strong interest shown by the French scientific community in SKA1 and to take advantage of the French community’s investment in SKA pathfinders, by developing within the same framework the service tasks that prepare SKA, and those that concern its precursors and pathfinders, mainly LOFAR and NenuFAR, while promoting synergies and highlighting common tasks. SKATE provides a common framework for the development of instrumentation, training and support to the community, as well as the development of tools for SKA1 and the European SRC. SKATE also facilitates for CNAP personnel to adapt their service.

SKATE’s service tasks are grouped into six categories :

- Instrumentation development for NenuFAR and SKA1.
- The management of LOFAR’s FR606 station, of NenuFAR, the governance of the French contribution to LOFAR and the governance of SKA-France.
- The operation of the observation stations : FR606 and NenuFAR.
- User support for FR606, LOFAR, NenuFAR and other pathfinders as well as the definition of the support to be given to SKA users, particularly in the context of the future European SKA Regional Center.
- The provision of FR606 data in local mode and NenuFAR (quality control, archiving, access) and the preparation of the French contribution to the SKA Regional Center.
- The development of algorithmic and methodological tools for SKA and its pathfinders as well as for the European SKA Regional Center.


Summary table of SNO SKATE’s service tasks and functional organisation chart

Tableau récapitulatif


National managers
Benoit Semelin (OBSPM) : benoit.semelin [at] observatoiredeparis.psl.eu
Jean-Mathias Griessmeier (OSUC) : jean-mathias.griessmeier [at] cnrs-orleans.fr

OSUs partners and local managers
OASU : Patrick Charlot (patrick.charlot [at] u-bordeaux.fr)
OCA : Chiara Ferrari (chiara.ferrari [at] oca.eu)
OMP : Mickaël Coriat (mickael.coriat [at] irap.omp.eu)
OSUPS : Mathieu Langer (mathieu.langer [at] universite-paris-saclay.fr)

[1An SKA precursor is an instrument located on one of the sites (e.g. MeerKAT, ASKAP), a pathfinder is an instrument labelled by SKA-O but not on site (e.g. LOFAR, NenuFAR). More info

Séminaires à venir

Vendredi 26 février 2021, 14h00
Téléconférence via Zoom,
Morphological Transformations and Quenching in Galaxies : from Simulations to Observations
LERMA-Observatoire de Paris-PSL
résumé :
The origins of the relation between galaxy structure and star formation is still debated. I will discuss recent efforts to advance in our understanding of how massive galaxies change their morphology and quench from z~3. Using several state of the art deep learning techniques, we try to link hydrodynamic cosmological simulations with observations from deep surveys to constrain the physical conditions and evolutionary tracks of galaxies.

Vendredi 5 mars 2021, 14h00
Visioconférence via Zoom,
Laboratory astrophysics studies of VUV and X-ray induced photodesorption from interstellar ice analogues
Mathieu BERTIN
résumé :
The recent advances in space and ground based telescopes (ALMA, NOEMA…) have allowed the detection of more and more molecules in the gas phase in the coldest regions of the interstellar medium - ISM (star-forming regions, protoplanetary disks…). The puzzling detection of these gaseous species, including small organic molecules, in media where the temperature is very low (~ 10-100 K), is currently a major and still open question, directly linked to the astrochemical richness. Most of the observed molecules are indeed expected to either directly form or accrete on the surface of dust grains, and cannot thermally desorb in the regions where they are detected. Their observation requires thus non-thermal desorption processes, among which the desorption induced by UV or X-ray photons – so-called photodesorption – is a promising candidate. However, its role still needs to be clarified, especially in the case of the desorption of small organics molecules for which both the quantitative yields and the underlying mechanisms are lacking.

I will present the outcomes of recent laboratory astrophysics studies base on the use of the monochromatic and tunable synchrotron radiation, dedicated to understand and quantify the photodesorption processes in both the vacuum UV (7-13,6 eV) and soft X-rays (500 – 1500 eV) energy ranges. The role played by the photon energy and of the molecular ice composition on the desorption yields will be highlighted, and a special focus will be made on the case of photodesorption of complex organics molecules.

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