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Plans de gestion des données : recommandations pour une gestion responsable et ouverte des données
No full textLe plan de gestion des données (PGD) s'est imposé en quelques années comme un élément structurant dupaysage de la recherche française et européenne. Exigé par l'Agence nationale de la recherche depuis 2019et obligatoire par défaut pour Horizon Europe depuis 2016, il constitue aujourd'hui un instrument centralde la gestion responsable et ouverte des données, essentielle à la qualité et à la reproductibilité de larecherche. Le PGD répond à une double ambition : garantir la rigueur scientifique tout en favorisant lepartage des données selon les principes FAIR.Pour autant, l’appropriation effective du PGD par les communautés scientifiques demeure limitée. Desenquêtes récentes mettent en évidence une méconnaissance persistante du PGD, ainsi que l’existence defreins récurrents (manque de temps, charge de travail supplémentaire, inquiétudes liées à la réutilisationdes données ou déficit de compétences dédiées…). Dans ce contexte, le PGD est encore fréquemmentenvisagé comme une obligation réglementaire davantage que comme un outil au service de la conduitescientifique.Ce décalage entre exigences institutionnelles et usages effectifs se traduit par une perception dominantedu PGD comme contrainte administrative, produit pour satisfaire à une obligation réglementaire plutôtque pour accompagner le processus scientifique. Il en résulte des pratiques hétérogènes, des modèles etoutils fragmentés, ainsi que des coûts de production et de mise à jour difficiles à rationaliser. Il interrogeplus largement la capacité du PGD à s’inscrire durablement dans les pratiques de recherche et à produireune réelle valeur ajoutée pour les équipes.La problématique centrale devient alors la suivante : comment concevoir et déployer des PGD qui, tout enrépondant aux exigences des financeurs et aux principes FAIR, constituent des outils opérationnels,durables et utiles pour les équipes de recherche, contribuant à réduire la charge administrative, à améliorerla qualité des données et à renforcer l’interopérabilité au sein de l’écosystème de la recherche ?Face à ces constats, l’évolution vers des PGD interopérables et machine actionable ouvre de nouvellesperspectives. En facilitant l’automatisation de certaines tâches, l’intégration aux systèmes d’informationexistants et la circulation des métadonnées, ces approches permettent d’envisager le PGD comme unvéritable outil d’aide à la décision, d’anticipation stratégique et d’optimisation des pratiques de recherche.Le présent document s'articule autour de trois parties principales :• Pourquoi adopter un plan de gestion des données ? Cette partie présente les bénéfices concrets pourles équipes de recherche : amélioration de la qualité scientifique, facilitation des collaborations etanticipation stratégique des besoins.• Recommandations pour l'élaboration de plans de gestion des données : Les recommandations sontstructurées selon trois niveaux d'action : le PGD de projet, le PGD de structure ou de plateforme, et lagestion des données à l'échelle institutionnelle.• Annexes : Des scénarios prospectifs illustrant l'usage des PGD dans divers contextes disciplinaires ontété élaborés en complément et sont présentés dans un document distinct
SimSDP, a Rapid Prototyping tool for Radio Astronomy: From NenuFAR Experiments to SKAO-Scale Simulation
No full textInternational audienceSimSDP is a rapid prototyping tool designed to provide early estimates of the computation times and energy consumption of SKAO's future SDP processor pipeline. This paper extends a previous proof-of-concept by: (1) exploring further parallelism through dataflow modeling of spectral parallelism with joint or distributed deconvolution, (2) simulating pipeline behavior on multi-core multi-node CPU architectures for multiscale data, (3) deploying parametric prototype pipelines using real-world data from the NenuFAR instrument. Experimental results show that SimSDP effectively supports design-space exploration by simulating three radio-interferometric imaging algorithms on HPC systems, with simulation uncertainty below 10%
GRB 241105A: a test case for GRB classification and rapid r -process nucleosynthesis channels
No full textInternational audienceABSTRACT Gamma-ray bursts (GRBs) offer a powerful window to probe the progenitor systems responsible for the formation of heavy elements through the rapid neutron capture (r-) process, thanks to their exceptional luminosity, which allows them to be observed across vast cosmic distances. GRB 241105A, observed at a redshift of , features a short initial spike (1.5 s) and a prolonged weak emission lasting about 64 s, positioning it as a candidate for a compact binary merger and potentially marking it as the most distant merger-driven GRB observed to date. However, the emerging ambiguity in GRB classification necessitates further investigation into the burst’s true nature. Prompt emission analyses, such as hardness ratio, spectral lag, and minimum variability time-scales, yield mixed classifications, while machine-learning-based clustering places GRB 241105A near both long-duration mergers and collapsar GRBs. We conducted observations using the James Webb Space Telescope (JWST) to search for a potential supernova counterpart. Although no conclusive evidence was found for a supernova, the host galaxy’s properties derived from the JWST observations suggest active star formation with low metallicity, and a sub-kpc offset of the afterglow from the host, which appears broadly consistent with a collapsar origin. Nevertheless, a compact binary merger origin cannot be ruled out, as the burst may plausibly arise from a fast progenitor channel. This would have important implications for heavy element enrichment in the early Universe
Quadrupole signature as a kinematic diagnostic to constrain bar properties: Implications for the Milky Way
No full textInternational audienceThe presence of a ‘butterfly’ or a quadrupole structure in the stellar mean radial velocity (⟨ V R ⟩) field of the Milky Way is well known from the Gaia and the APOGEE surveys. Past studies have indicated that a stellar bar can excite such a quadrupole feature in the ⟨ V R ⟩ distribution. However, a systematic study investigating the co-evolution of bar and quadrupole structure is largely missing. Furthermore, the question of whether this quadrupole structure in ⟨ V R ⟩ can be used as a robust kinematic diagnostic to constrain bar properties, particularly for the Milky Way, is still beyond our grasp. Here, we investigate the bar-induced quadrupole feature using a suite of isolated N -body models forming prominent bars and a sample of Milky Way-like barred galaxies from the TNG50 cosmological simulation. We demonstrate that the properties of the quadrupole (strength, length, and orientation) are strongly correlated with the bar properties, regardless of the choice of the thin- or thick-disc stars; thereby making the quadrupole feature an excellent kinematic diagnostic for constraining the bar properties. In the presence of spirals, the estimator that takes into account the phase-angle of m = 4 Fourier moment serves as a more appropriate estimator for measuring the length of the quadrupole. Furthermore, we constructed a novel Gaia -like mock dataset from a simulated bar model, while incorporating the dust extinction and the broad trends of observational errors of the Gaia survey. The quadrupole properties (strength and length) estimated from those Gaia -like mock data are larger (∼35 − 45 per cent) when compared to their true values. We showed that the majority of this effect is due to the uncertainty in the parallax measurement. This demonstrates that the quadrupole structure in Gaia data is likely a result of dominant Gaia parallax errors and biases, almost masking the true inherent signature of the MW bar
The π-IR survey: A 10,000 deg 2 Far-IR legacy survey with PRIMAger
No full textInternational audienceThe π-IR survey is a community-driven, legacy-scale far-infrared mapping program designed to cover approximately π steradians (~25%) of the sky using the PRIMAger instrument aboard the PRIMA mission. Operating across 24–260 µm, PRIMAger combines hyperspectral imaging, polarimetry, and exceptional mapping speed to deliver a transformative dataset for extragalactic and cosmological science. The survey will provide confusion-limited photometry in PHI (R ~ 8) and confusion-limited photometry in PPI (R ~ 4), and polarimetry enabling detailed investigations of galaxy evolution, dust-obscured star formation, interstellar dust, and large-scale structure out to redshift z ~ 4. Leveraging PRIMAger’s high survey efficiency, π-IR will cover wide with both spectral and polarimetric modes. It will detect over 16 million galaxies, offering the statistical power needed to study cosmic environments and structure formation across time. The survey is designed to work in concert with NASA’s Roman Space Telescope and ESA’s Euclid mission, providing far-infrared counterparts to their high-resolution near-infrared imaging and spectroscopy. This synergy will enable robust multi-wavelength studies of stellar mass assembly, dust physics, and the evolution of galaxies at cosmic noon and beyond. While extragalactic and cosmological science are the core drivers, the π-IR dataset will also support diverse astrophysical investigations, including Solar System small bodies and proto-planetary disks. Crucially, the π-IR survey is structured as an open, community-oriented initiative: all raw and value-added data products will be released to the public immediately, maximizing accessibility, scientific return, and engagement across the astronomical community
The Ionosphere of Uranus as Revealed by JWST
No full textInternational audienceAbstract The first spectroscopic observations of Uranus by the James Webb Space Telescope were obtained in January 2023. Using these observations, we explored the physical properties of the planet's ionosphere through the analysis of near‐infrared spectra. We found that both the northern and southern aurora were present; confirmed by localized column density enhancements. The median ionospheric temperature across the disk was 415 13 K, which is at least 300 K lower than measured by Voyager 2 in 1986, making these the lowest temperatures ever recorded. Surprisingly, auroral temperatures are not elevated in the south, and are only enhanced by tens of Kelvin in the north, indicative of limited heating or very efficient transport away from the auroral regions. Significant non‐auroral ionospheric structure is observed, including a dark band aligned with the magnetic dip equator, revealing the first imprints of Uranus's magnetic field on its ionosphere
Rotation periods of asteroids serendipitously observed by the NASA/ Kepler K2 mission
No full textInternational audienceContext . Understanding the rotational periods of asteroids is crucial for gaining insights into their internal structures, compositions, and collisional histories. NASA’s Kepler Space Telescope, during its K2 extension (2014-2018), serendipitously observed numerous asteroids while surveying the ecliptic plane, providing a unique photometric dataset. Aims . By analyzing photometric data from the K2 mission, we aimed to determine the rotational periods of asteroids that crossed Kepler ’s field of view, focusing on objects with an apparent magnitude of 19 or brighter that appeared in the Kepler target pixel files at least ten times. Methods . We developed an algorithm to identify asteroid crossings in the Kepler data and extract photometric light curves. The Lomb–Scargle periodogram method was employed to determine the rotational periods from the extracted light curves due to its robustness in handling unevenly sampled data. Noise and systematic errors were mitigated through photometric corrections using co-trending basis vectors. Results . We extracted and analyzed 4,596 light curves from 2,418 asteroids observed during the Kepler /K2 mission. This allowed us to compute rotation periods for 559 asteroids. We found that 375 of these asteroids had previously known periods. The rotation periods determined for 295 of the asteroids in this study agree with existing asteroid rotation periods from the literature, validating our approach. We report new rotation periods and their light curve amplitudes for 184 asteroids, expanding the catalog of known asteroid rotation periods. Conclusions . The analysis of rotation periods from the Kepler K2 mission data has provided valuable insights into the physical characteristics of main-belt asteroids. Our results are consistent with existing data and expand the catalog of known asteroid rotation periods. These findings contribute to our understanding of asteroid dynamics and will aid future research in planetary science and asteroid exploration
Spectral Hole Burning in Eu:YSO for Low-frequency Acceleration Sensing
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An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345
No full textInternational audienceA crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential vital link needs testing by characterizing exoplanets around chemically-diverse stars. We present the discovery of two planets orbiting the metal-poor, kinematic thick-disc K-dwarf TOI-2345. TOI-2345 b is a super-Earth with a period of 1.05 d and TOI-2345 c is a sub-Neptune with a period of 21 d. In addition to the target being observed in four TESS sectors, we obtained five CHEOPS visits and 26 radial velocities from HARPS. By conducting a joint analysis of all the data, we find TOI-2345 b to have a radius of 1 . 504+ 0 . 047 -0 . 044 R ⊕ and a mass of 3 . 49 ± 0 . 85 M ⊕ ; and TOI-2345 c to have a radius of 2 . 451+ 0 . 045 -0 . 046 R ⊕ and a mass of 7 . 27+ 2 . 27 -2 . 45 M ⊕ . To explore chemical links between these planets and their host star, we model their interior structures newly accounting for devolatized stellar abundances. TOI-2345 adds to the limited sample of well-characterized planetary systems around thick disc stars. This system challenges theories of formation and populations of planets around thick disc stars with its Ultra-Short Period super-Earth and the wide period distribution of these two planets spanning the radius valley.</div