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An Electron Plasma Camera for the Plasma Observatory ESA mission
No full textInternational audienceMeasuring both the energy spectrum and the 3D distribution of charged particles at high temporal resolution is one of the main challenges in space plasma instrumentation. The conventional solution to date has been to use multiple sensors that couple the native quasi-2D instantaneous field of view of the electrostatic top-hat analyser with a scanning electrostatic deflection system.For the Plasma Observatory ESA mission, we proposed an alternate strategy that reduces the level of resources required for rapid plasma measurements at sub-ion scale in the magnetospheric environment. The Electron Plasma Camera (EPC) is based on the donut-shaped electrostatic analyser topology that do not require any electrostatic scanning to provide a hemispheric field-of-view of the surrounding plasma.This optics is manufactured through the selective metallization of a high-resolution 3D printed polymer. It is coupled to a 256-pixel imaging detection system that uses the detection technology that was demonstrated on the Solar Orbiter mission. EPC’s fully integrated front-end electronics takes advantage of the high-geometric factor of its electrostatic optics to enable the capture of high temporal resolution images of electron phase space. We present the expected capability of the instrument in the key science regions the Plasma Observatory mission will encounter, and some of the major science questions related to multi-scale phenomena the Plasma Observatory mission will address with its unique data set
Euclid preparation. Cosmology Likelihood for Observables in Euclid (CLOE). 3. Inference and Forecasts
No full textInternational audienceThe Euclid mission aims to measure the positions, shapes, and redshifts of over a billion galaxies to provide unprecedented constraints on the nature of dark matter and dark energy. Achieving this goal requires a continuous reassessment of the mission's scientific performance, particularly in terms of its ability to constrain cosmological parameters, as our understanding of how to model large-scale structure observables improves. In this study, we present the first scientific forecasts using CLOE (Cosmology Likelihood for Observables in Euclid), a dedicated Euclid cosmological pipeline developed to support this endeavour. Using advanced Bayesian inference techniques applied to synthetic Euclid-like data, we sample the posterior distribution of cosmological and nuisance parameters across a variety of cosmological models and Euclid primary probes: cosmic shear, angular photometric galaxy clustering, galaxy-galaxy lensing, and spectroscopic galaxy clustering. We validate the capability of CLOE to produce reliable cosmological forecasts, showcasing Euclid's potential to achieve a figure of merit for the dark energy parameters and exceeding 400 when combining all primary probes. Furthermore, we illustrate the behaviour of the posterior probability distribution of the parameters of interest given different priors and scale cuts. Finally, we emphasise the importance of addressing computational challenges, proposing further exploration of innovative data science techniques to efficiently navigate the Euclid high-dimensional parameter space in upcoming cosmological data releases
Euclid preparation: Towards a DR1 application of higher-order weak lensing statistics
No full textInternational audienceThis is the second paper in the HOWLS (higher-order weak lensing statistics) series exploring the usage of non-Gaussian statistics for cosmology inference within \textit{Euclid}. With respect to our first paper, we develop a full tomographic analysis based on realistic photometric redshifts which allows us to derive Fisher forecasts in the (, ) plane for a \textit{Euclid}-like data release 1 (DR1) setup. We find that the 5 higher-order statistics (HOSs) that satisfy the Gaussian likelihood assumption of the Fisher formalism (1-point probability distribution function, 1-norm, peak counts, Minkowski functionals, and Betti numbers) each outperform the shear 2-point correlation functions by a factor on the forecasts, with only marginal improvement when used in combination with 2-point estimators, suggesting that every HOS is able to retrieve both the non-Gaussian and Gaussian information of the matter density field. The similar performance of the different estimators\inlinecomment{, with a slight preference for Minkowski functionals and 1-point probability distribution function,} is explained by a homogeneous use of multi-scale and tomographic information, optimized to lower computational costs. These results hold for the mass mapping techniques of the \textit{Euclid} pipeline: aperture mass, Kaiser--Squires, and Kaiser--Squires plus, and are unaffected by the application of realistic star masks. Finally, we explore the use of HOSs with the Bernardeau--Nishimichi--Taruya (BNT) nulling scheme approach, finding promising results towards applying physical scale cuts to HOSs
Identification of low-energy kaons in the ProtoDUNE-SP detector
No full textInternational audienceThe Deep Underground Neutrino Experiment (DUNE) is a next-generation neutrino experiment with a rich physics program that includes searches for the hypothetical phenomenon of proton decay. Utilizing liquid-argon time-projection chamber technology, DUNE is expected to achieve world-leading sensitivity in the proton decay channels that involve charged kaons in their final states. The first DUNE demonstrator, ProtoDUNE Single-Phase, was a 0.77 kt detector that operated from 2018 to 2020 at the CERN Neutrino Platform, exposed to a mixed hadron and electron test-beam with momenta ranging from 0.3 to 7 GeV/c. We present a selection of low-energy kaons among the secondary particles produced in hadronic reactions, using data from the 6 and 7 GeV/c beam runs. The selection efficiency is 1% and the sample purity 92%. The initial energies of the selected kaon candidates encompass the expected energy range of kaons originating from proton decay events in DUNE (below 200 MeV). In addition, we demonstrate the capability of this detector technology to discriminate between kaons and other particles such as protons and muons, and provide a comprehensive description of their energy loss in liquid argon, which shows good agreement with the simulation. These results pave the way for future proton decay searches at DUNE
Euclid Quick Data Release (Q1) First study of red quasars selection
No full textInternational audienceRed quasars constitute an important but elusive phase in the evolution of supermassive black holes, where dust obscuration can significantly alter their observed properties. They have broad emission lines, like other quasars, but their optical continuum emission is significantly reddened, which is why they were traditionally identified based on near- and mid-infrared selection criteria. This work showcases the capability of the \Euclid space telescope to find a large sample of red quasars, using \Euclid near infrared (NIR) photometry. We first conduct a forecast analysis, comparing a synthetic catalogue of red QSOs with COSMOS2020. Using template fitting, we reconstruct \Euclid-like photometry for the COSMOS sources and identify a sample of candidates in a multidimensional colour-colour space achieving completeness for mock red QSOs with contaminants. To refine our selection function, we implement a probabilistic Random Forest classifier, and use UMAP visualisation to disentangle non-linear features in colour-space, reaching completeness and purity. A preliminary analysis of the candidates in the \Euclid Deep Field Fornax (EDF-F) shows that, compared to VISTA+DECAm-based colour selection criteria, \Euclid's superior depth, resolution and optical-to-NIR coverage improves the identification of the reddest, most obscured sources. Notably, the \Euclid exquisite resolution in the filter unveils the presence of a candidate dual quasar system, highlighting the potential for this mission to contribute to future studies on the population of dual AGN. The resulting catalogue of candidates, including more the 150 000 sources, provides a first census of red quasars in \Euclid Q1 and sets the groundwork for future studies in the Euclid Wide Survey (EWS), including spectral follow-up analyses and host morphology characterisation
The Venus Emissivity Mapper (VEM): instrument science performance requirements derived from VERITAS and EnVision
No full textInternational audienceWe present the Venus Emissivity Mapper (VEM) onboard NASAs Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy (VERITAS) and ESAs (EnVision) Venus orbiter missions. The VEM instrument (on EnVision called VenSpec-M), is a multispectral imager for mapping of the Venus surface and its lower atmosphere. This is realized by observation through narrow-band atmospheric windows present in the near-infrared spectral region around 1 μm. For the first time, VEM will provide a global Venus coverage of > 70% with a high signal-to-noise ratio on the order of 100 to detect thermal emissions like volcanic activity, surface rock composition, water abundance and cloud formation. Since VEM for VERITAS and VenSpec-M for EnVision are being developed almost simultaneously, the instrument development approach can be made very efficient. By tailoring the science level, interface and environmental requirements of both missions to a joint requirements baseline, a single instrument design can be established. Focusing on the science requirement breakdown, this paper presents the key scientific requirements derived from VERITAS and EnVision and how they translate into verifiable technical instrument requirements. The VEM/VenSpec-M project is in its preliminary design phase. The instrument preliminary design review (PDR) is planned in 2025 for VERITAS and EnVision. Two flight models (FMs) are currently scheduled for delivery to the VERITAS S/C in 2028 and one FM to the EnVision S/C in 2029. First VEM/VenSpec-M data obtained from Venus orbit is expected after launch of the two missions currently scheduled in 2031
Improving Morphological Networks for Learning Image-to-Image Transforms
No full textInternational audienceReplacing convolution with morphological operations in trainable layers has received significant attention lately. Among the various strategies that have emerged, smooth morphological layers have shown strong potential and flexibility, as a single layer can behave either like a (pseudo-)erosion or a (pseudo-)dilation depending on the sign and value of its trainable control parameter. In this work, we build upon the so-called SMorph layer by introducing a harmonized formulation that addresses previously identified asymptotic limitations when learning grayscale erosion and dilation. We also investigate and compare two strategies (a novel penalty term in the training loss and shared-weight layers) to improve the learning of grayscale opening and closing operations in two-layer networks. Finally, we evaluate the performance of this improved SMorph layer on a salt-and-pepper denoising task in a four-layer network architecture, and compare it with other morphological and convolutional networks
A JWST/MIRI view of κ Andromedae b: Refining its mass, age, and physical parameters
No full textInternational audienceContext. κ And b is a substellar companion with a mass near the planet–brown dwarf boundary orbiting a B9IV star at ~50–100 au. Estimates of its age and mass vary, which has fueled a decade-long debate. Additionally, the atmospheric parameters (Teff 1650–2050 K and log(g) 3.5–5.5 dex) remain poorly constrained. The differences in atmospheric models and inhomogeneous datasets contribute to the varied interpretations.Aims. We aim to refine the characterization of κ And b by using mid-infrared data to capture its full bolometric emission. Combined with near-infrared (NIR) measurements, we aim to constrain Teff, log(g), and the radius to narrow down the uncertainties in age and mass.Methods. We obtained JWST/MIRI coronagraphic data in the F1065C, F1140C, and F1550C filters and recalibrated existing NIR photometry using an updated ATLAS stellar model. We used MIRI color–magnitude diagrams to probe the likelihood of species (e.g., CH4, NH3, and silicates). We compared the H and F1140C colors and magnitudes of the companion to isochrones to constrain the age and mass. We then modeled its spectral energy distribution with atmospheric models to refine the estimates of Teff, radius, and log(g) and to constrain age and mass using evolutionary models.Results. Cloudy atmosphere models fit the spectral energy distribution of κ And b best. This is consistent with its L0/L2 spectral type and its position near silicate-atmosphere field objects in the MIRI color–magnitude diagram. We derived an age of 47 ± 7 Myr and a mass of 17.3 ± 1.8 MJup by weight-mean combining the models. Atmospheric modeling yielded Teff = 1791 ± 68 K and a radius of 1.42 ± 0.06 RJup. This improves the precision by ~30% over previous estimates. log(g) was constrained to 4.35 ± 0.07 dex, which is an improvement in the precision by ~70% relative to the most precise literature value of 4.75 ± 0.25 dex.Conclusions. Our new mass estimate places κ And b slightly above the planet–brown dwarf boundary determined by the deuterium-burning limit. Our age estimate is ~75% more precise than previous values and aligns the object with the Columba association (42 Myr). The derived Teff suggests silicate clouds, but this needs to be confirmed spectroscopically. MIRI data were crucial to refine the radius and temperature, which led to stronger constraints on the age and mass (both dependent on the model) and improved the overall characterization of κ And b
Goals and Structure of Envision’s VenSpec Ground-Based Observations Working Group
No full textInternational audienceEnVision is an ESA mission to Venus that will orbit Venus in 2034 and aims to provide a holistic view of Earth’s sister planet from its inner core to its upper atmosphere [1]. The mission is developed in partnership with NASA and has science goals that address the study of the planet’s geologic history, its current geologic and atmospheric active processes and the evolution of its interior, surface and climate as a coupled system. To address these goals, EnVision will be placed in a low altitude polar orbit that will allow the mission instruments to acquire data of the planet, its surface and atmosphere at exquisite spatial and spectral resolution. EnVision’s instruments include a suite of three spectrometers grouped together in the VenSpec suite [2]: VenSpec-U (190-380 nm) [3], VenSpec-H (1.16-2.48 µm) [4] and VenSpec-M (0.79-1.51 µm) [2]. The VenSpec suite will map trace gases and atmospheric chemistry, search for volcanic gas plumes above and below the clouds, map surface emissivity and composition and will investigate Venus atmosphere and surface emissivity and composition.The Venus Ground-Based Observations Working Group has been established in support of EnVision and its VenSpec instrument with the objective of enhancing the scientific return of the mission through coordinated Earth-based observations. The goals of the Working Group are: (1) To provide spectroscopic data that will be useful to test observation strategies and retrieval pipelines with the VenSpec instrument, across the whole range of available wavelengths that can be used to characterize Venus atmosphere and it surface. (2) To coordinate the monitoring of Venus atmosphere, its dynamics and its variability providing knowledge about the evolution of atmospheric features and the global characterization of the atmosphere in the decade since Akatsuki to EnVision. (3) To support and prepare for Venus observations during Envision’s science phase in 2035 and onwards, providing context to the observations that will be acquired by Envision and its VenSpec instrument. Examples of current and planned Venus observations and monitoring include observing campaigns with ground-based telescopes such as the Canadian France Hawaiian Telescope (CFHT), NASA’s IRTF or ALMA among others. Members of the WG also run frequent observing campaigns at Calar Alto Observatory and plans for long-term monitoring of Venus with Earth-Orbit CubeSats [5]; and contributions from amateur astronomers providing spatially resolved observations of Venus clouds and surface.We here explain the structure of the working group, the open channels for information sharing, and the potential time lines for observing campaigns. This presentation is an open call to the community to provide Venus observational data and to join the Working Group
Determination of the Abundance of Mercury from the Hg ii Line at 5677.10 Å. XXV. HD 32964 B (66 Eri B)
No full textInternational audienceThe weak line of Hg ii located at 5677.10 Å is not detected in a series of ESPaDOnS I profiles of the bright HgMn SB2 star HD 32964 (66 Eri). This non-detection sets a limit on the abundance of mercury below which this line ceases to be useful. Line synthesis is used to measure the abundances of twenty elements in one component of the system, 66 Eri B, the HgMn star. The following excesses/deficiencies are found: helium (–0.70 dex), carbon (–0.52), oxygen (–0.70), neon (–0.30), magnesium (–0.40), silicon (–0.70), phosphorus (0.00), calcium (–0.85), scandium (–0.48), titanium (+0.36), chromium (+0.52), manganese (+0.52), iron (–0.70), gallium (0.00), strontium (–0.09), ytrium (+2.00), zirconium (0.00), xenon (0.00), baryum (+1.60) and mercury (+4.73). The status of 66 Eri B as a HgMn star is reinforced