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Le handicap, une priorité pour toutes et tous
No full textLe handicap concerne tout le monde ! Il appelle à la solidarité et à un combat pour l’égalité. La question est un révélateur des conditions de travail ordinaires et un possible vecteur d’amélioration des modalités de recrutement ou d’évaluation. Elle engage une conception de la société et des choix éthiques et politiques pour la recherche et ses institutions. Il y a cinquante ans, Simone Veil portait une loi d’orientation majeure en faveur des personnes handicapées, en particulier pour le droit au travail en milieu ordinaire. En 2005 était votée une grande loi sur le handicap. Vingt ans plus tard, malgré les progrès, la situation des personnes handicapées reste souvent invivable. Les mentalités ont changé, mais la loi de 2005 est mal appliquée et une disposition législative de 2019 est scandaleusement écartée. Le syndicat SNCS-FSU a fait du handicap une priorité, qu’il compte faire adopter avec le SNESUP-FSU par tous les établissements de recherche et d’enseignement supérieur. À l’occasion des 20 ans de la loi de 2005 et des 50 ans de la loi de 1975, ensemble ils proposent un dossier spécial sur le handicap. Ce dossier est porté par la section nationale Handicap du SNCS-FSU, avec la contribution du SNESUP-FSU. Une vingtaine de textes formulent des propositions qui s’appuient sur des enquêtes historiques ou sociologiques, statistiques ou juridiques, et qui sont portées par des perspectives philosophiques, anthropologiques ou épistémologiques. Un premier groupe de textes présente la valeur universelle des questions liées au handicap, l’évolution des pratiques et des imaginaires, une synthèse des lois en cours et le combat pour la prise en compte du handicap mené par la section nationale Handicap du SNCS. Un deuxième ensemble porte sur le handicap dans les établissements de recherche et d’enseignement supérieur. Il dresse un état des lieux. Il souligne le validisme des institutions et les enjeux d’une réflexion sur les temporalités de la recherche ou les critères de l’excellence. Il fait des propositions pour les recrutements, les processus sélectifs et l’aide aux aidants. Il rend compte d’une enquête importante sur le handicap dans la recherche publique. Une dernière série de textes expose des recherches sur ou à partir du handicap : une perspective de sciences sociales, la présentation d’un institut de recherche et formation, une réflexion sur les manières d’apprendre du handicap, un débat sur les bienfaits ou les effets pervers de l’usage des techniques. Ce dossier est aussi une lettre ouverte aux institutions et établissements qui sont invités à agir en urgence pour mettre fin aux discriminations et à être à la hauteur des enjeux : le fonctionnement et les finalités mêmes de la recherche publique
The Galaxy Activity, Torus, and Outflow Survey (GATOS). VI. Black hole mass estimation using machine learning
No full textInternational audienceThe detailed feeding and feedback mechanisms of active galactic nuclei (AGNs) are not yet well known. For low-luminosity AGNs, obscured AGNs, and late-type galaxies, the masses of their central black holes (BH) are difficult to determine precisely. Our goal with the GATOS sample is to study the circum-nuclear regions and, in the present work, to better determine their BH mass, with more precise and accurate estimations than those obtained from scaling relations. We used the high spatial resolution of ALMA to resolve the CO(3–2) emission within ∼100 pc around the supermassive black hole (SMBH) of seven GATOS galaxies and try to estimate their BH mass when enough gas is present in the nuclear regions. We studied the seven bright ( L AGN (14 − 150 keV)≥10 42 erg/s) and nearby (< 28 Mpc) galaxies from the GATOS core sample. For the sake of comparison, we first searched the literature for previous BH mass estimations. We also made additional estimations using the M BH – σ relation and the fundamental plane of BH activity. We developed a new method using supervised machine learning to estimate the BH mass either from position-velocity diagrams or from first-moment maps computed from ALMA CO(3–2) observations. We used numerical simulations with a large range of parameters to create the training, validation, and test sets. Seven galaxies had sufficient gas detected, thus, we were able to make a BH estimation from the ALMA data: NGC 4388, NGC 5506, NGC 5643, NGC 6300, NGC 7314, NGC 7465, and NGC 7582. Our BH masses range from 6.39 to 7.18 log( M BH / M ⊙ ) and are consistent with the previous estimations. In addition, our machine learning method has the advantage of providing a robust estimation of errors with confidence intervals. The method has also more growth potential than scaling relations. This work represents the first step toward an automatized method for estimating M BH using machine learning
Unveiling the bulge–disc structure, AGN feedback, and baryon landscape in a massive spiral galaxy with Mpc-scale radio jets
No full textInternational audienceWe study the bulge–disc components and stellar mass distribution in the fast-rotating, highly massive spiral galaxy 2MASX J23453268−0449256, which is distinguished by extraordinary radio jets extending to Mpc scales. Using high-resolution multiwavelength Hubble Space Telescope (HST) observations and multiparameter panchromatic spectral energy distribution (SED) fitting, we derive estimates of key properties, such as the star formation rate, total baryonic mass in stars, and the characteristics of warm dust. Our findings, validated at a spatial resolution of approximately 100 pc, reveal a pseudo-bulge rather than a classical bulge, as well as a small nuclear bar and resonant ring, challenging traditional models of galaxy formation. Furthermore, the absence of tidal debris and the highly symmetric spiral arms within a rotationally supported stellar disc suggest a peaceful co-evolution of the galactic disc and its central supermassive black hole (SMBH). Notably, the galaxy exhibits suppressed star formation in its central region, which may be influenced by feedback from the central accreting SMBH, producing powerful radio jets. Detailed multiwavelength studies of potential star-forming gas show that while hot X-ray gas cools in the galaxy’s halo, new stars do not form in the centre, likely due to this feedback. This study raises important questions about the efficient fuelling and sustained collimated jet activity in J2345−0449, highlighting the need for a better understanding of the central black hole’s properties. The exceptional rarity of galaxies like 2MASX J23453268−0449256 presents intriguing challenges in uncovering the physical processes behind their unique characteristics
Euclid Structural-Thermal-Optical Performance
No full textInternational audienceThe Euclid system performance is defined in terms of image quality metrics tuned to the weak gravitational lensing (WL) cosmological probe. WL induces stringent requirements on the shape and stability of the VIS instrument system point spread function (PSF). The PSF is affected by error contributions from the telescope, the focal plane and image motion, and is controlled by a global error budget with error allocations to each contributor. Aims. During spacecraft development, we verified through a structural-thermal-optical performance (STOP) analysis that the built and verified telescope with its spacecraft interface meets the in-orbit steady-state and transient image quality requirements. Methods. For the purposes of the STOP analysis, a detailed finite-element mathematical model was set up and a standard set of test cases, both steady-state and transient, was defined, comprising combinations of worst-case boundary conditions. Results. The STOP analysis addressed the interaction of all spacecraft components in transmitting temperature-induced loads that lead to optical train deformation. The results of the prelaunch analysis demonstrated that temperature-induced optical perturbations will be well below the allowable limits for all permitted observing conditions. During the first year in orbit, we used the STOP analysis predictions to help interpret the measured performance as a function of environmental variables. Unpredicted disturbances were discovered and unexpected sensitivities were revealed. In-orbit temperature variations are small (<300 mK) and so are their effects on the telescope structure, but they are detected in the time histories of the image quality metrics and are a non-negligible factor in the PSF stability budget demanded by the WL science. Taking everything into account, our analysis confirms the excellent overall performance of the telescope
First joint absorption and T-based metallicity measured in a GRB host galaxy at using JWST/NIRSpec
No full textInternational audienceWe present the first gamma-ray burst (GRB) host galaxy with a measured absorption line and electron temperature (T) based metallicity, using the temperature sensitive [OIII]4363 auroral line detected in the JWST/NIRSpec spectrum of the host of GRB 050505 at redshift . We find that the metallicity of the cold interstellar gas, derived from the absorption lines in the GRB afterglow, of 12 + log(O/H) is in reasonable agreement with the temperature-based emission line metallicity in the warm gas of the GRB host galaxy, which has values of 12 + log(O/H) = 7.800.19 and 7.960.21 for two common indicators. When using strong emission line diagnostics appropriate for high-z galaxies and sensitive to ionisation parameter, we find good agreement between the strong emission line metallicity and the other two methods. Our results imply that, for the host of GRB050505, mixing between the warm and the cold ISM along the line of sight to the GRB is efficient, and that GRB afterglow absorption lines can be a reliable tracer of the metallicity of the galaxy. If confirmed with a large sample, this suggest that metallicities determined via GRB afterglow spectroscopy can be used to trace cosmic chemical evolution to the earliest cosmic epochs and in galaxies far too faint for emission line spectroscopy, even for JWST
Cryogenic characterization of FBK NUV-HD-Cryo 3T SiPM sensors for the DUNE photon detection system
No full textInternational audienceThe Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino experiment based in the USA and composed of a Near Detector (ND) complex at Fermi National Laboratory (FNAL), and a Far Detector (FD) complex located at the Sanford Underground Research Facility (SURF) 1300 km distant. DUNE will study neutrino oscillations looking for unresolved issues of the Standard Model of particle physics (SM) such as CP violation in the leptonic sector, neutrino mass ordering and others, starting from the early 2030s. The FD, with a mass of 17 kt, that will exploit both ionization and scintillation signals to detect neutrino interactions with Argon. Scintillating photons in LAr will be detected by the photon detection system (PDS) based on light collectors coupled to Silicon Photomultipliers (SiPMs). During a test campaign, different laboratories of the collaboration performed an investigation of the best SiPM candidates that fulfill the DUNE FD requirements. We identified two models of SiPM, produced by Hamamatsu Photonics K.K. (HPK) and Fondazione Bruno Kessler (FBK), respectively. In this paper, we focus on the FBK selected model showing its main features. We will describe the characterization protocol, the results at both room and cryogenic temperatures and the photon detection efficiency measurements
Precision Measurements of Higgs Hadronic Decay Modes at the FCC-ee
No full textInternational audienceThe expected precision at the FCC-ee on the product of Higgs boson production cross sections times branching ratios of hadronic decays is presented. This study provides the first comprehensive determination of all major hadronic Higgs decay modes in a combined fit at future colliders, using both Higgs-strahlung () and Vector boson fusion () production processes, with a full treatment of interference effects in the final state. It assumes four identical IDEA detectors collecting collisions at and GeV. The combination of all channels across both energies, with full covariance between production and decay modes, yields a production cross-section times branching-ratio precision at the percent to per-mil level for the dominant hadronic final states (). These results provide a comprehensive input to the determination of Higgs coupling projections at the FCC-ee, and they establish for the first time sensitivity to the rare decay , demonstrating that FCC-ee has the potential to provide evidence of the strange-quark Yukawa coupling
A Self-Consistent Model of the Ultra High-Energy Gamma-Ray Emission of Pulsar Wind Nebulae: Insights from LHAASO and ATNF Catalogs
No full textInternational audiencePulsar wind nebulae (PWNe) are the dominant Ultra-high-energy (UHE) gamma-ray sources in the LHAASO catalog suggesting that they are the dominant leptonic PeVatrons in our Galaxy. Despite this, still very little is known about their UHE gamma-ray emission, their number in the Galaxy, or their contribution to the gamma-ray emission of our Galaxy. In this work, we propose a self-consistent data-driven model of the UHE gamma-ray emission of PWNe based on the ATNF and LHAASO catalogs. More specifically, we build a model of the UHE gamma-ray emission of PWNe that preserves the statistical relationships in the ATNF catalog and reproduces the number of PWNe detected in the LHAASO catalog. To cope with the limited data available in the LHAASO catalog when performing fits on gamma-ray data, we introduce the concept of censored regression that allows to also use the information provided by unresolved sources. Using our model, we find that reproducing the number of PWNe detected by LHAASO requires either fractions of misaligned pulsars smaller () than usually found in the literature, or that some of the associations of PWNe to ATNF pulsars made by LHAASO may not be true. In both cases, we find that in order to reach self-consistency between radio and gamma-ray data, it is necessary that the majority of the unidentified sources in the LHAASO catalog are PWNe associated to an unseen pulsar. Moreover, using our model we also find that the contribution of unresolved PWNe to the total (diffuse) gamma-ray background measured by LHAASO in the range is always smaller than (). We conclude that PWNe mostly contribute to the source component of the UHE gamma-ray sky, while having almost no imprint on its diffuse component
A few ideas to promote inclusion
No full textNational audiencePromoting diversity, equity, inclusion and accessibility (DEIA) is both a legal and professional responsibility in French research institutions. This paper presents practical strategies to foster inclusive work environments within French research units. We summarize the regulatory context, key findings from the INSU-AA prospective on discrimination, and fundamental principles for promoting equity. We discuss approaches to mitigate implicit biases across all career stages, from early education to retirement, and outline strategies for equitable recruitment and career advancement. Concrete initiatives in one of our units (LESIA/LIRA) are described, including internal communications, exhibitions, and accessible pedagogical activities. The creation of a dedicated commission within the unit council ensures coordinated DEIA efforts, legitimized by institutional support and methodical planning. By sharing these experiences, we provide actionable guidance for research units seeking to advance DEIA in science
Mouvement relativiste des particules chargées dans un champ électrique, partie 2 : application aux premiers accélérateurs linéaires de particules, Van de Graaff et Linac (1935-1950)
No full textNouvel article faisant suite à la première partie (les rayons cosmiques en tant que premiers outils de physique nucléaire avant 1950) qui est en ligne ici: https://cnrs.hal.science/hal-05329933v1Nous avons présenté dans un précédent article (https://cnrs.hal.science/hal-05329933v1) quel fut l'usage des rayons (particules) cosmiques en tant qu'outil de physique nucléaire jusqu'en 1955, ayant permis d'étudier grâce aux chambres de Wilson plongées dans un champ magnétique, les particules produites par collision ou désintégration atmosphérique. Nous abordons dans cette seconde partie de niveau L2/L3 les mouvements relativistes des particules chargées dans un champ électrique avec application aux premiers accélérateurs linéaires apparus au même moment (Van de Graaff, Linac), mais de moindre énergie que les cosmiques, développés avant la création des grandes installations internationales telles celles du CERN après 1955 (non abordées ici)