General introduction of the laboratory

The AstroParticle and Cosmology laboratory (APC) is a Joint Research Unit (UMR) created in 2005. APC gathers about 75 permanent researchers, and about fifty engineers, technicians and administrative staff. Including non-permanent staff (PhD students, post-doctoral fellows, foreign visitors), some 200 people make up this structure, which is led by the University of Paris (UP), the CNRS (represented by three of its institutes: mainly IN2P3, but also INSU and INP), the CEA (DSM/IRFU) and the Observatoire de Paris, and the CNES.

The laboratory is centered around four main themes:

Cosmology: the objective of cosmology is to understand the history and structure of the Universe. The understanding of the primordial universe, the study of the cosmological microwave background, the identification of dark energy are some of the aspects of the research carried out in the laboratory, which is strongly involved in the Planck space mission and the Qubic and POLARBEAR experiments in Argentina and Chile, and in wide field observations to better understand dark energy (the Rubin telescope and the Euclid space mission).

Gravitation: With the first detections of LIGO and Virgo, gravitational astronomy has become a reality. This new field of astronomy will develop in the next decade with the second generation ground-based detectors, in particular Advanced Virgo (and its future improvements) and the third generation, with the European Einstein Telescope project, as well as in space with the LISA mission led by ESA. Members of the Gravitation group play an important role in the development of each of these instruments, both at the instrumental level and in the exploitation of scientific data.

High energy astrophysics: violent phenomena in the Universe are studied in order to better understand the physical processes that modulate the formation of cosmic structures. The laboratory is strongly involved in the observation of X-rays (SVOM, ATHENA) and gamma rays (INTEGRAL, HESS-CTA), ultra-high energy cosmic rays (JEM-EUSO) and neutrinos (ANTARES-KM3NeT/ARCA).

Particles: the group is interested in different aspects of particle physics, in particular in the physics of neutrinos. These extremely light particles interact very little with matter and are therefore irreplaceable messengers of phenomena that occur at cosmic distances from us. The study of their properties is therefore important for the field of astroparticles. The laboratory is strongly involved in a complete identification of the oscillation phenomenon (DoubleCHOOZ, DUNE, KM3NeT/ORCA). Researchers of the group are also involved in the direct search for dark matter with the DarkSide experiment, as well as in the study of the Higgs boson with the ATLAS experiment at the LHC and the Future Ring Collider (FCC) at CERN.

In addition to the experimental and observational activities described above, the themes covered by the laboratory are studied by the Theory group. More specifically, the research of the members of the group covers all theoretical aspects of cosmology and astroparticles, from the foundations of general relativity and unification theories, such as string and brane theory, to the understanding of cosmic acceleration phenomena, the phenomenology of high-energy cosmic particles and neutrino physics. Numerical simulations are a complementary tool for the analysis of complex phenomena, from accretion-ejection around compact objects to the formation of large cosmological structures.

The laboratory also has an extensive program of interdisciplinary collaborations, notably with the geosciences (muography, geoneutrinos and cosmic neutrinos, gravity detectors for seismometry) in the context of the UnivEarthS Laboratory of Excellence.

APC has close links with the Centre de Cosmologie Physique de Paris (PCCP) chaired by George Smoot, Nobel Prize winner in 2006, which develops research, training and knowledge dissemination activities in the research perimeter of the laboratory.

R&D and data analysis. The laboratory seeks to develop its intervention upstream and downstream of astroparticle projects. A particular importance is thus given to the R&D aiming at the emergence of new instrumentations and the implementation of new techniques for data analysis.

In the field of R&D, some strong axes are: bolometry in the millimeter and submillimeter domains, cryogenic microelectronics, photodetection (characterization of photomultipliers, scintillators for high energies), laser stabilization.

Data processing also receives special attention within the laboratory. The APC laboratory opened in September 2010 a space data processing center, the François Arago Center, to support space missions requiring complex data processing. The Center, closely connected to the CNRS computing center in Lyon (CC-IN2P3), provides a number of services to its users, such as access to computers, analysis routines, storage servers, distribution of new analysis software, and above all, a team of experts in computer science and data science.

Technical services. The technical services of the APC (mechanics, electronics, experimental techniques and computer science) allow the laboratory to participate in the design of new experiments, in the prototyping, in the follow-up of the construction, in the processing and in the exploitation of the data. Each project of the laboratory is allocated resources that allow it to fulfill the commitments made by the laboratory. A certain number of heavy equipment are also used by the laboratory teams or some external teams: clean rooms (optics, system integration), machining center, space simulator, low noise and low frequency electronics test room, photodetection laboratory.

The APC laboratory is particularly involved in a number of space missions (50% of its technical forces are dedicated to this). This imposes a quality approach and a particular attention to project management. Over the last few years, the laboratory has set up a quality and project support unit which monitors quality in the laboratory and provides support for laboratory projects in terms of product assurance analysis methods. In addition, all the space activities of the APC contribute to the know-how of the University of Paris in this field, competences which must be joined together within a space pole gathering the activities of training and research relating to space, in all the laboratories and the UFR of the University.

Teaching and diffusion of knowledge. The laboratory is particularly attentive to its mission of diffusion of knowledge: to make known the scientific fields approached, the outstanding results, but also the technical achievements and more generally the way in which the laboratory lives from day to day. All the teachers-researchers of the laboratory and some researchers participate in the teaching of the University of Paris. The laboratory also wishes to involve students in its various activities, through internships (about 100 per year) or theses. The laboratory's website is aimed at a wide range of audiences: the scientific community, but also the general public interested in scientific and technical advances, students of all levels, professors and journalists.

International relations

The APC laboratory is finally involved in an important network of international collaborations:

  • experiments located on four continents
  • space missions in liaison with the major space agencies, in particular CNES and the European Space Agency (ESA), but also NASA and the Japanese and Chinese agencies,
  • a privileged partnership with the major astroparticle physics laboratories including the International Associated Laboratory (LIA) with KIPAC of Stanford, the Pierre Binetruy Center, an International Research Lab (IRL) in association with the University of Berkeley, the LIA ALFA in Argentina, the LIA LEPLB with Kurchatov and collaborations with the Kavli-IPMU in Japan

This translates into rich programs of meetings and exchanges such as the annual cycle of conferences "Cosmological Frontiers in Fundamental Physics" with the Perimeter Institute (Waterloo, Canada) and the Solvay Institutes (Brussels), or the participation in the international PhD program IDAPP with a group of Italian universities.