The Astronomy and Astrophysics Arising Across Africa (5A) network aims at benefiting from MRSEI funding to strengthen the existing Europe-Africa network for collaborations in astronomy and exploit it to build a strong CNRS-led proposal in response to the next MSCA Staff Exchanges (SE) call in March 2022. In May 2020, we submitted the 5A proposal to the MSCA-RISE-2020 European call. Led by CNRS, the consortium is a network of about 300 European and African researchers. The proposal aimed at strengthening and expanding Africa-Europe collaborations in astronomy in the optical and infrared domains. It addresses 6 of the 17 United Nations Sustainable Development Goals (SDGs), which the EU has committed to implement in its internal and external policies. The network includes 12 partners, 6 in Europe and 6 in Africa, with 2.3M€ of requested funds to achieve 500 secondments and organise 6 thematic schools. In its evaluation, the proposal reached the 70% threshold grade, but was not selected. Following the new SE call rules, we will limit the project to 1.65M€ of requested funds to achieve 360 secondments, focusing on those necessary to achieve the key scientific goals of the project, which we will define with help from the MRSEI funding. Before the submission of the 5A project to the SE call, the network hopes to achieve the following objectives thanks to the MRSEI funding: (i) improve the overall project, by addressing the remarks of the Evaluation Summary Report (shortcomings will be corrected and strengths will be reinforced) and by organising a three-day workshop; (ii) strengthen the visibility of the project and its potential impact by liaising with policy-makers and industrial partners and setting up a strategic Stakeholders’ Board; (iii) get valuable feedback on the proposal from a consultancy agency that will proofread the draft before submission and provide expert recommendations to implement in the final version. MRSEI funding is therefore crucial to improve the chance of success of the proposal and, in the long run, support Europe-Africa strategic collaboration in this field. This will impact both Africa and Europe to the benefit of science and society. As other regions are heavily investing in Africa, Europe will benefit from consolidating scientific links with this continent that already has a strong heritage and potential in astronomy. Moreover, when funded, 5A will be a fundamental asset for French scientific diplomacy in Africa by reinforcing scientific bilateral collaborations between Europe and Africa.

Owing to a high-resolution cathodoluminescence systematic study of carbonaceous chondrites and NASA OSIRIS-REx returned samples, O-Return is a 4 years ANR project aiming at gaining new information on the conditions of formation (e.g. condensation, crystallization, annealing) of refractory inclusions and chondrules, the first solids in the Solar System, and on their astrophysical setting (e.g., shock waves, impacts). Through the different tasks of O-Return that we will emplace, our approach will consist: i) to perform an unprecedented high-resolution cathodoluminescence study of olivines and pyroxenes, the most abundant phases in magnesian (type I) chondrules, and to extend the survey to Amoeboid Olivine Aggregates (AOA), the most common type of refractory inclusions in carbonaceous chondrites. This study will give us an unique inventory of their mode of crystallization and their variability, ii) to synthesize thin films of Mg-rich olivine and pyroxene doped with known CL activator concentrations (Al, Mn, Cr) at the level of a few ppm and to acquire their optical characteristic for serving as new standards, in order to upgrade high-resolution cathodoluminescence imaging to a quantitative mode of detection of trace elements and lattice defects, and iii) to model olivine and pyroxene crystallization conditions/modes in both chondrites and OSIRIS-REx returned materials to gain insights on 1) locations for chondrule/AOA formation in the disk, 2) their putative astrophysical settings, and 3) the dynamical regimes reigning in the protoplanetary disk. To achieve this work, the O-Return project will develop an original and transdisciplinary research merging expertises from both materials and planetary sciences between two renowned laboratories J-L LAGRANGE and Centre of Research on Hetero-Epitaxy and Applications (CRHEA). The originality of this project lies in the use of high-resolution cathodoluminescence, which has never been fully exploited on extraterrestrial objects, and the synthesis of unique standards, which will allow a quantified interpretation of the CL signature of chondrites and OSIRIS-REx returned samples. Owing to this innovative combination, the expectation is to provide a quantum leap improvement in our understanding of the early evolution of the Solar System and Youg Stellar Objects.

Hydrodynamic turbulence is considered as a prototype of systems far from equilibrium. Its phenomenological description relies on Richardson and Kolmogorov’s idea that energy cascades through scales. In many complex flows, Kolmogorov turbulence appears to be valid within a reduced range of scales. Out of this range, energy is carried along scales thanks to different physical processes like the interaction of coherent structures and non-linear waves. This is the case of quantum turbulence, that is observed in superfluids like 3He and 4He, Bose-Einstein condensates (BEC) made of dilute alkaline gases and even in optical non-linear systems with the so-called quantum fluids of light. Quantum turbulence is a non-equilibrium phenomenon that involves processes with a large spatial and temporal scale separation. The most manifest quantum effect in superfluid turbulence is the presence of quantum vortices, whose circulation is quantised. During the last decade, thanks to the development of new experimental technics, quantum vortices have been successfully visualised in superfluids. It is now possible to study vortex dynamics in BEC and superfluid helium. Using particles to sample the flow, the differences between classical and quantum turbulence have been enlightened. However, despite this progress, experimental techniques are not yet able to simultaneously sample and excite all the scales of quantum turbulence. Many fundamental questions are still open in this kind of systems. The goal of this proposal is to study the dynamics of particles in superfluids and their interaction with vortices mainly focussing on the physical phenomena laying at the crossover between classical and quantum regimes. It brings standard tools used in the theoretical description of classical turbulence to the quantum case. For that purpose, it borrows tools from statistical mechanics and non-linear physics while using state-of-the-art techniques in computational fluid dynamics. To that extent simulations of the Gross-Pitaevskii model and the Hall-Vinen-Bekharavich-Khalatinikov model, will be performed. The dynamics of particles will be also integrated in those models. In particular, this proposal aims at determining how well particles sample superfluid vortices and how important is their interaction with the flow. It does not focus in only one type of superfluid system but rather aims at unveiling the universal aspects of quantum turbulence. The team is composed of experts on classical hydrodynamic and quantum turbulence, with strong knowledge on computational and theoretical tools for fluid dynamics. Their different skills ensure a good synergy in the team. This project is timely because of the different experiments carried in Europe and US with superfluid Helium, atomic BECs and quantum fluids of light. The expected theoretical and numerical results will improve the understanding of recent experiments.

How did our Galaxy form? What is its place, and ours, in the cosmic evolution? This ARCHEOGAL ANR project aims at unveiling the Milky Way disc formation process, taking advantage of the privileged position of the P.I in the European Gaia-ESO Survey (GES, a five years project using 300 nights of the ESO Very Large Telescope) and the ESA Gaia mission, whose time-lines overlap perfectly the present project time schedule. Just as the history of life was deduced by examining rocks, Galactic Archaeology expects to unveil the history of the Milky Way by analysing stars. Thanks to the complementary scientific exploitation of GES and Gaia, ARCHEOGAL aims at building up an unprecedentedly extensive and homogeneous cosmic-time evolving chemo-dynamical picture of the Milky Way disc. To this purpose, the project tasks, organised following the GES and Gaia data releases, will analyse the disc physical and chemical properties, linking them to the processes that led the Milky Way to form and evolve as a disc-type galaxy, in the more general context of galaxy evolution. In particular, the project work program is centred on: 1) The GES stellar spectra parameterisation and the scientific validation of the Gaia/RVS stellar parameters. 2) From GES and Gaia chemical element abundances, the analysis of the Galactic disc chemical substructures. 3) From GES spectro-photometric distances, followed by Gaia astrometric data, the study of the structural properties of chemically defined disc populations. 4) Thanks to GES+Gaia radial velocities and Gaia proper motions, the analysis of existent chemo-kinematical and chemo-dynamical correlations. 5) From combined Gaia+GES data, the estimation of precise stellar ages and the reconstruction of chemo-dynamical temporal gradients, to be compared with present scenarios of disc formation. This ANR funding will be crucial to ensure the team's leading position in GES and also to strength the French contribution to the combined GES and Gaia science exploitation.

The detection of gravitational waves (GWs) in 2015 has been labeled as one of the “major scientific discoveries of the 21st century” by most science magazines. GWs have opened a new window on our universe, at the intersection between fundamental physics and astrophysics. The first detection, the merger of two 30 Solar mass black holes, came as an immense surprise to the astrophysical world as all black holes we knew off had masses around 10-15 Solar mass. This discovery immediately raised the questions: “where do merging black holes come from?” Black hole mergers are thought to come from the evolution of isolated massive binary stars and from N-body interactions in dense star clusters but the relative contribution of both formation channels is still unclear. This is because our knowledge of the evolution of massive stars, and their binary interactions is still very partial and the study of clusters is limited by uncertain initial conditions. Because of their different initial conditions and different evolutionary pathways, the binary and cluster merger channels have never been compared in a consistent, systematic fashion. In 2022, the next Virgo/LIGO observations (O4) should yield several hundreds of binary black hole mergers. With this statistical sample, we expect to finally be able to answer to the question of the origins of black hole mergers. Provided accurate models and appropriate statistics are used, the interpretation of GW events has the potential to provide information on massive stars which is unavailable with current electromagnetic observations. The first goal of this ANR project COSMERGE is to determine the importance of each formation channel and the main parameters ruling massive binary evolution. The second goal of COSMERGE is to determine the typical host galaxies and formation times of black hole merger progenitors. Based on our findings about how, when and where GW progenitors form, our final goal will be to make discriminating predictions for detections with the sensitivities of future instruments. The key to the astrophysical interpretation of GW events is the multidisciplinary combination of a robust statistical analysis with state-of-the-art astrophysical models. With COSMERGE, we will infer the main astrophysical parameters leading to black hole mergers using hierarchical Bayesian analysis of the O4 data, based on our newly developed astrophysical prior models. We will use a large scale high resolution cosmological simulation to model star formation both in isolated binaries and massive star clusters, with a novel technique we have been developing over the past years. In combination with various binary population synthesis models and simulations for cluster evolution, we will provide the first self-consistent end-to-end comparison of large scale models of black hole mergers in both clusters and binaries. These will be used as priors for a hierarchical Bayesian analysis of the O4 detections, and lead to a confident determination of the main channels leading to black hole mergers. The COSMERGE project will be lead by Astrid Lamberts, who will hire a postdoctoral researcher and PhD student at the Laboratoire Lagrange in Nice. Astrid Lamberts is one of the only GW astrophysicists in France. With her record for interdisciplinary research projects, the COSMERGE project will build on local expertise and develop GW astrophysics in Nice. This project will strongly improve our understanding of the origin of binary black hole mergers, which is one of the core science objectives of the Virgo and LIGO projects. Its results will be relevant to different astrophysical communities such as massive stellar evolution and global star formation and will also be disseminated within a public audience.