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Novel Benchmark for NER in the Wastewater and Stormwater Domain
No full textInternational audienceEffective wastewater and stormwater management is essential for urban sustainability and environmental protection. Extracting structured knowledge from reports and regulations is challenging due to domainspecific terminology and multilingual contexts. This work focuses on domain-specific Named Entity Recognition (NER) as a first step towards effective relation and information extraction to support decision making. A multilingual benchmark is crucial for evaluating these methods. This study develops a French-Italian domain-specific text corpus for wastewater management. It evaluates state-of-the-art NER methods, including LLM-based approaches, to provide a reliable baseline for future strategies and explores automated annotation projection in view of an extension of the corpus to new languages
Exploring the presence of a fifth force at the Galactic Center
No full textInternational audienceAims. We investigate the presence of a Yukawa-like correction to Newtonian gravity at the Galactic Center, leading to a new upper limit on the intensity of such a correction.Methods. We performed a Markov chain Monte Carlo (MCMC) analysis using the astrometric and spectroscopic data of star S2 collected at the Very Large Telescope by GRAVITY, NACO, and SINFONI instruments, covering the period from 1992 to 2022.Results. The precision of the GRAVITY instrument allows us to derive the most stringent upper limit at the Galactic Center for the intensity of the Yukawa contribution (∝ αe−λr) of |α|< 0.003 for a scale length of λ = 3 ⋅ 1013 m (∼ 200 AU). This is an improvement on all estimates obtained in previous works by roughly one order of magnitude
The Secondary Component of the Extremely Low Mass Ratio Massive Binary HD 165246 Revealed by GHOST
No full textInternational audienceIn the pursuit of understanding the multiplicity of massive stars, the OWN Survey has undertaken spectroscopic monitoring of hundreds of targets over the past 20 yr. This effort has led to the discovery of new single-lined spectroscopic binaries. Characterizing the unseen companions of these systems is crucial to deriving precise stellar parameters, including the mass of each component, and constraining formation models for massive binary systems. In this paper, we aim to physically and evolutionarily characterize the stellar components of the massive binary HD 165246. We analyzed spectra obtained by the OWN Survey and used Kepler's second mission (K2) photometry, from which we determined the physical parameters of the system. Thanks to the high-resolution capabilities of the new echelle spectrograph Gemini/GHOST, we could directly detect spectral features of the secondary component for the first time. A very low mass ratio for the system is confirmed (q ~ 0.16), making this binary one of the few extremely low mass ratio systems known. The primary star has a mass of Ma = 22 ± 1 M⊙ and a radius of Ra = 7.0 ± 0.1 R⊙, while the secondary star has a mass of Mb = 3.4 ± 0.1 M⊙ and a radius of Rb = 2.22 ± 0.02 R⊙. Stellar evolution models indicate that the system has undergone approximately two million years of evolution since its formation. Moreover, the secondary star is identified as a pre-main-sequence object, progressing toward the zero-age main sequence. This paper illustrates the power of high-resolution spectrographs such as GHOST in finding much lower mass, previously unseen stellar components of binary star systems
Deep Rest-UV JWST/NIRSpec Spectroscopy of Early Galaxies: The Demographics of C IV and N-emitters in the Reionization Era
No full textInternational audienceJWST has recently discovered a subset of reionization era galaxies with ionized gas that is metal-poor in oxygen and carbon but heavily enriched in nitrogen. This abundance pattern is almost never seen in lower-redshift galaxies but is commonly observed in globular cluster stars. We have recently demonstrated that this peculiar abundance pattern appears in a compact (≃20 pc) metal-poor galaxy undergoing a strong burst of star formation. This galaxy was originally selected based on strong C IV emission, indicating a hard radiation field rarely seen locally. In this paper, we present JWST/NIRSpec observations of another reionization-era galaxy known to power strong C IV emission, the z = 7.04 gravitationally lensed galaxy A1703-zd6. The emission-line spectrum reveals this is a metal-poor galaxy ( ) dominated by a young stellar population ( Myr) that powers a very hard ionizing spectrum (C IV equivalent width, EW = 19.4 Å, He II EW = 2.2 Å). The interstellar medium is highly enriched in nitrogen ( ) with very high electron densities (8–19 × 104 cm‑3) and extreme ionization conditions rarely seen at lower redshift. We also find intense CIV emission (EW ≳ 20 Å) in two new z ≳ 6 metal-poor galaxies. To put these results in context, we search for UV line emission in a sample of 737 z ≳ 4 galaxies with NIRSpec spectra, establishing that 40%(30%) of systems with [O III]+Hβ EW > 2000 Å have N IV] (C IV) detections with EW > 5 Å(> 10 Å). These results suggest high N/O ratios, and hard ionizing sources appear in a brief phase following a burst of star formation in compact high-density stellar complexes
JADES: measuring reionization properties using Lyman-alpha emission
No full textInternational audienceLy is the transition to the ground state from the first excited state of hydrogen (the most common element). Resonant scattering of this line by neutral hydrogen greatly impedes its emergence from galaxies, so the fraction of galaxies emitting Ly is a tracer of the neutral fraction of the intergalactic medium (IGM), and thus the history of reionization. In previous works, we used early JWST/NIRSpec data from the JWST Advanced Deep Extragalactic Survey (JADES) to classify and characterize Ly emitting galaxies (LAEs). This survey is approaching completion, and the current sample is nearly an order of magnitude larger. From a sample of 795 galaxies in JADES at , we find evidence for Ly emission in 150 sources. We reproduce the previously found correlation between Ly escape fraction () - Ly rest-frame equivalent width () and the negative correlation between Ly velocity offset - . Both and decrease with redshift (), indicating the progression of reionization on a population scale. Our data are used to demonstrate an increasing IGM transmission of Ly from . We measure the completeness-corrected fraction of LAEs () from . An application of these values to the results of previously utilized semi-analytical models suggests a high neutral fraction at (). Using an updated fit to the intrinsic distribution of results in a lower value in agreement with current works (). This sample of LAEs will be paramount for unbiased population studies of galaxies in the EoR
HYPERION: Broad-band X-ray-to-near-infrared emission of quasars in the first billion years of the Universe
No full textInternational audienceAims. We aim to characterize the X-ray-to-optical/near-infrared(NIR) broad-band emission of luminous quasars (QSOs) in the first gigayear (Gyr) of cosmic evolution in order to decipher whether or not they exhibit differences compared to the lower-z QSO population. Our goal is also to provide a reliable and uniform catalog of derivable properties for these objects (from fitting their spectral energy distribution), such as bolometric and monochromatic luminosities, Eddington ratios, dust extinction, and the strength of the hot dust emission. Methods. We gathered all available photometry –from XMM-Newton proprietary data in X-rays to rest-frame NIR wavelengths– for the 18 QSOs in the HYPERION samples (6.0 ≤ z ≤ 7.5). For sources lacking uniform NIR coverage, we conducted NIR observations in the J, H, and K bands. To increase the statistical robustness of our analysis across the UV-to-NIR region, we add 36 additional sources to our sample from the E-XQR-30 sample with 5.7 ≲ z ≲ 6.6. We characterized the X-ray/UV emission of each QSO using average SEDs from luminous Type 1 sources and calculated bolometric and monochromatic luminosities. Finally, we constructed a mean SED extending from the X-rays to the NIR bands. Results. We find that the UV-optical emission of these QSOs can be modeled with templates of z ∼ 2 luminous QSOs. We observe that the bolometric luminosities derived while adopting some bolometric corrections at 3000 Å (BC3000 Å) largely used in the literature are slightly overestimated, by 0.13 dex, as they also include reprocessed IR emission. We estimate a revised value of BC3000 Å = 3.3, which can be used to derive Lbol in z ≥ 6 QSOs. We provide a subsample of 11 QSOs with rest-frame NIR photometry; these show a broad range of hot dust emission strength, with two sources exhibiting low levels of emission. Despite potential observational biases arising from nonuniform photometric coverage and selection biases, we produce an X-ray-to-NIR mean SED for QSOs at z ≳ 6 that is a good match to templates of lower-redshift, luminous QSOs up to the UV–optical range, with a slightly enhanced contribution from hot dust in the NIR
OGLE-2016-BLG-1195Lb: A Sub-Neptune Beyond the Snow Line of an M-dwarf Confirmed by Keck Adaptive Optics
No full textInternational audienceWe present the analysis of high-resolution follow-up observations of OGLE-2016-BLG-1195 using Laser Guide Star Adaptive Optics with Keck, seven years after the event's peak. We resolve the lens, measuring its flux and the relative source-lens proper motion, thus finding the system to be a Mp = 10.08 ± 1.18M⊕ planet orbiting an M-dwarf, ML = 0.62 ± 0.05M⊙, beyond the snow line, with a projected separation of r⊥ = 2.24 ± 0.21 au at DL = 7.45 ± 0.55 kpc. Our results are consistent with the discovery paper, which reports values with 1σ uncertainties based on a single mass–distance constraint from finite source effects. However, both the discovery paper and our follow-up results disagree with the analysis of a different group that also present the planetary signal detection. The latter utilizes Spitzer photometry to measure a parallax signal claiming the system is an Earth-mass planet orbiting an ultracool dwarf. Their parallax signal though is improbable since it suggests a lens star in the disk moving perpendicular to or counter to the Galactic disk rotation. Moreover, microlensing parallaxes can be impacted by systematic errors in the photometry. Therefore, we reanalyze the Spitzer photometry using a pixel level decorrelation model to detrend detector systematics. We find that we cannot confidently recover the same detrended light curve that is likely dominated by systematic errors in the photometric data. The results of this paper act as a cautionary tale that a careful understanding of detector systematics and how they influence astrophysical constraints is crucial
An insight into recent PM<sub>1</sub> aerosol light scattering properties and particle number concentration variabilities at the suburban site ATOLL in Northern France
No full textInternational audienceAerosol particles in the PM1 fraction considerably influence the climate-related effects of aerosols and impact human health despite representing very variable fractions of the total aerosol mass concentration. Aerosol optical measurement techniques (aerosol light scattering) may not be sufficiently effective for detecting all particles in the PM1 fraction, particularly regarding number concentration. The present study investigates temporal variations of aerosol light scattering properties and particle number concentration (PNC) at different size modes in the PM1 fraction at the atmospheric site ATOLL (The Atmospheric Observations in Lille), Northern France from January 2018 to February 2023. The total scattering coefficient σsp decreased annually by 6 % and 8 % at 525 and 635 nm, respectively. Maximum annual changes occur in winter and summer seasons with a decrease above 10 % per year. Although the backscattering coefficient (σbsp) at 525 nm significantly decreased in winter, this did not result in a significant overall decline over time. Despite a decrease in aerosol light scattering, PNC exhibited a notable annual increase in concentration of N20-30 nm and N30-60 nm, which led to an increase in the total N20-800 nm size range. N20-30nm increased by 10 % annually, with the highest increase by 37 % in spring. Both traffic and photooxidative processes influenced PNCs, underscoring the need for a more comprehensive investigation of the detailed particle number size distribution to assess air quality and the health effects of increased ultrafine PNC at urban/suburban sites in Europe
Using an Artificial Neural Network to Assess Several Rainfall Estimation Algorithms Based on X-Band Polarimetric Variables in West Africa
No full textInternational audienceQuantitative precipitation estimation using polarimetric radar in attenuation-prone frequency (X-band) in tropical regions characterized by convective rain systems with high intensities is a major challenge due to strong attenuations that can lead to total signal extinction over short distances. However, some authors have addressed this issue in Benin since 2006 in the framework of the African Monsoon Multidisciplinary Analysis program. Thus, with an experimental setup consisting of an X-band polarimetric weather radar (Xport) and a network of rain gauges, investigations have started on the subject with the aim of improving rainfall estimates. Based on simulated polarimetric variables and using a Multilayer Perceptron artificial neural network, several bi-variable and tri-variable algorithms were assessed in this study. The data used in this study are of two categories: (i) simulated polarimetric variables (Rayleigh reflectivity Z, horizontal attenuation Ah, horizontal reflectivity Zh, differential reflectivity Zdr, and specific differential phase Kdp) and rainfall intensity (R) obtained from Rain Drop Size Distribution (DSD) measurements used for algorithm evaluation (training and testing); (ii) polarimetric variables measured by the Xport radar and rainfall intensity measured by rain gauges used for algorithm validation. The simulations are performed using the T-matrix code, which leverages the scattering properties of spheroidal particles. The DSD measurements taken in northwest Benin were used as input for this code. For each spectrum, the T-matrix code simulates multiple variables. The simulated data (first category) were divided into two parts: one for training and one for testing. Subsequently, the best algorithms were validated with the second category of data. The performance of the algorithms during training, testing, and validation was evaluated using metrics. The best selected algorithms are A1:R(Z,Kdp) and A12:R(Zdr,Kdp) (among the bi-variable); B2:R(Zh,Zdr,Kdp) and B3:R(Ah,Zdr,Kdp) (among the tri-variable). Tri-variable algorithms outperform bi-variable algorithms. Validation with observation data (Xport measurements and rain gauge network) showed that the algorithm B3:R(Ah,Zdr,Kdp) performs better than B2:R(Zh,Zdr,Kdp)
Sea Surface Temperature Forecasting Using Foundational Models: A Novel Approach Assessed in the Caribbean Sea
No full textInternational audienceSea surface temperature (SST) plays a pivotal role in air–sea interactions, with implications for climate, weather, and marine ecosystems, particularly in regions like the Caribbean Sea, where upwelling and dynamic oceanographic processes significantly influence biodiversity and fisheries. This study evaluates the performance of foundational models, Chronos and Lag-Llama, in forecasting SST using 22 years (2002–2023) of high-resolution satellite-derived and in situ data. The Chronos model, leveraging zero-shot learning and tokenization methods, consistently outperformed Lag-Llama across all forecast horizons, demonstrating lower errors and greater stability, especially in regions of moderate SST variability. The Chronos model's ability to forecast extreme upwelling events is assessed, and a description of such events is presented for two regions in the southern Caribbean upwelling system. The Chronos forecast resembles SST variability in upwelling regions for forecast horizons of up to 7 days, providing reliable short-term predictions. Beyond this, the model exhibits increased bias and error, particularly in regions with strong SST gradients and high variability associated with coastal upwelling processes. The findings highlight the advantages of foundational models, including reduced computational demands and adaptability across diverse tasks, while also underscoring their limitations in regions with complex physical oceanographic phenomena. This study establishes a benchmark for SST forecasting using foundational models and emphasizes the need for hybrid approaches integrating physical principles to improve accuracy in dynamic and ecologically critical regions