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Unveiling the evolution of the CO excitation ladder through cross-correlation of CONCERTO-like experiments and galaxy redshift surveys
No full textInternational audienceContext: Rotational CO transitions, while acting as a foreground for [C II] line-intensity mapping (LIM) experiments, trace the physical conditions of cold gas in galaxies at lower redshifts. Studying these transitions is also crucial for improving component-separation methods as LIM sensitivity increases. Aims: Galaxy-evolution models have so far predicted only the total CO LIM signal. We explore the potential of cross-correlating millimeter-wave LIM data with spectroscopic galaxy surveys to constrain individual CO-line contributions, measure the CO-background spectral line energy distribution (SLED), and derive the cosmic molecular gas density, , up to . Methods: We built 12 light cones of from the Simulated Infrared Extragalactic Sky (SIDES) simulation. By analyzing cross-power spectra between different CO transitions and the galaxy density field, we recovered the CO background SLED. Combining it with bias-weighted line intensities yielded . We also assessed the detectability of the CO(4--3) cross-power spectrum with a CONCERTO-like experiment. Results: For a realistic spectroscopic depth, the CO background SLED is accurately recovered up to with uncertainties. Reconstructing from millimeter LIM data requires an excitation correction relative to CO(1--0). Interloper-induced variance does not prevent precise estimation. In the two-star-formation-mode SIDES model, starbursts dominate the SLED at but do not bias estimates from . However, CONCERTO lacks the sensitivity to detect the COgalaxy cross-power on relevant scales, even under ideal conditions
The cosmic web's Lyman- glow at ; varying hydrodynamic models, dust, and wide-field, narrow-band imaging detection
No full textInternational audienceThe diffuse glow of the cosmic web in Lyman- emission has long been predicted, yet remained elusive to direct wide field detection. We present theoretical calculations that, when compared with recent observations made using the Condor Array Telescope in New Mexico reported in Lanzetta et al. 2024, point to its discovery at . Synthetic Lyman- surface brightness maps are constructed from five state-of-the-art hydrodynamic simulations (Illustris-TNG, SIMBA, EAGLE, CROCODILE, and Sherwood), incorporating dust attenuation, star formation, collisional excitation, and recombination physics. Our cosmic web Lyman- surface brightness predictions are consistent with the UV excess detected at high significance in the recent deep, wide field, narrow-band imaging Condor data. The calculations presented here thus demonstrate that diffuse Lyman- emission is observable with current (and next-generation) wide field low surface brightness facilities, opening the path to direct cartographic mapping of the cosmic web. These findings mark a turning point: for the first time, cosmology moves beyond inference from absorption and high-density peaks, into panoramic imaging of the faint intergalactic scaffolding that underpins structure formation in the Universe
Beyond Stage IV: Quasar and Galaxy Clustering and the Fundamental Physics of the 2040s
No full textInternational audienceStage IV galaxy surveys (DESI, 4MOST, MOONS, Euclid) are establishing precision constraints on cosmological parameters through baryon acoustic oscillations and redshift-space distortions, yet fundamental questions on neutrino masses, inflationary physics, and the nature of gravity remain beyond their reach. We present a science case for next-generation wide-field spectroscopic surveys targeting with simultaneous observations of thousands of galaxies, quasars, and emission-line galaxies. Such surveys would deliver transformative advances: (i) cosmological constraints on absolute neutrino masses (), three times more stringent than Stage IV, enabling resolution of the neutrino mass hierarchy; (ii) detection of primordial non-Gaussianity at the level of , probing multi-field inflation; (iii) measurements of structure growth spanning cosmic time to constrain dark energy and test gravitational modifications. Achieving these goals requires revolutionary advances in spectroscopic multiplexing ( simultaneous spectra), sub- redshift precision at scale, and field-level inference techniques exploiting higher-order clustering statistics. We demonstrate that the proposed Wide-field Spectroscopic Telescope concept provides a technically feasible and scientifically compelling path to unlock the physics of neutrinos, inflation, and gravity that will remain inaccessible to Stage IV surveys
Mesozoic magmatism in the Andes of southern Ecuador and northern Peru: Tectonic insights from whole-rock chemistry and zircon petrochronology
No full textInternational audienceThe southern Ecuador–northern Peru region marks the transition between the northern and central Andes. This study reconstructs the Mesozoic magmatic history of this key region by integrating petrography, Usingle bondPb geochronology, whole-rock and zircon geochemistry, and εHf(t) and δ18O zircon isotopic data from plutonic rocks. Our results indicate that much of the Mesozoic magmatism occurred in an extensional arc setting, with magmatic reservoirs progressively incorporating more depleted, mantle material, while crustal contributions diminished through time. Magmatic reservoirs evolved both spatially and temporally, beginning with an extensive Triassic arc dominated by granitoids exhibiting strong crustal signatures at least until 220 Ma. This was followed by mildly enriched signatures associated with a stationary Jurassic to Early Cretaceous arc active between ∼190 and ∼ 126 Ma. Somewhere in between 126 and 104 Ma, the arc underwent a significant westward migration, potentially driven by slab rollback, which coincided with the opening of the Celica–Lancones Basin and the subsequent emplacement of the Late Cretaceous Celica–Lancones arc onto oceanic basement. This migration is consistent with westward shifts observed in central Ecuador and Colombia but contrasts with coeval eastward migration documented in central and southern Peru. In addition, new Usingle bondPb ages challenge current interpretations of a missing Jurassic arc in northern Peru by providing clear evidence that Jurassic magmatism extended at least as far south as 6°S
First baseline study on polymetallic passive biomonitoring of Polycarpa aurata in coral reef ecosystems in Southeast Sulawesi, Indonesia.
No full textInternational audienceThis pioneering study investigates the use of the tunicate Polycarpa aurata for assessing polymetallic pollution inSoutheast Sulawesi, Indonesia. Over the course of one year, encompassing both rainy and dry seasons, potentiallytoxic elements (PTE) such as metal elements were examined in the tunic and soft body of P. aurata. The researchrevealed site-specific variations in element trace concentrations, with a mining site exhibiting elevated levels ofmultiple metals (like As 12.65 μg/g DW, Cd 0.34 μg/g DW, Co 31.17 μg/g DW, Cu 10.88 μg/g DW and Ni173.50 μg/g DW). A correlation was observed between metal concentrations in P. aurata and those in sedimentand suspended particles. Comparing the 2 tissues analysed (soft body and tunic), we note that certain metalelements, including arsenic (BSAF 8,99), cadmium (6,38), copper (2,84), and zinc (5,28), accumulated preferentiallyin the soft body of P. aurata, while nickel accumulation was minimal compared to sediment levels (BSAFNi 1,12). This study establishes a baseline for passive biomonitoring of Indonesian coral reefs, demonstrating thatascidians like P. aurata are effective candidates for monitoring metal pollution in these marine environments. Thefindings contribute to addressing contemporary environmental challenges by highlighting the potential of marineorganisms in chemical monitoring and biomonitoring programs for pollutant identification and environmentalquality assessment
ArchesWeather: An efficient AI weather forecasting model at 1.5° resolution
No full textInternational audienceOne of the guiding principles for designing AI-based weather forecasting systems is to embed physical constraints as inductive priors in the neural network architecture. A popular prior is locality, where the atmospheric data is processed with local neural interactions, like 3D convolutions or 3D local attention windows as in Pangu-Weather. On the other hand, some works have shown great success in weather forecasting without this locality principle, at the cost of a much higher parameter count. In this paper, we show that the 3D local processing in Pangu-Weather is computationally sub-optimal. We design ArchesWeather, a transformer model that combines 2D attention with a column-wise attention-based feature interaction module, and demonstrate that this design improves forecasting skill. ArchesWeather is trained at 1.5° resolution and 24h lead time, with a training budget of a few GPU-days and a lower inference cost than competing methods. An ensemble of four of our models shows better RMSE scores than the IFS HRES and is competitive with the 1.4° 50-members NeuralGCM ensemble for one to three days ahead forecasting. Our code and models are publicly available at https://github.com/gcouairon/ArchesWeather
Diet composition and trophic ecology of two Antarctic storm-petrel species
No full textInternational audienceAvailability and quality of food shape the distribution and movements of animal populations. In sympatric species, sharing limited resources, coexistence is typically achieved through niche segregation. However, information on dietary niches is lacking particularly for small and elusive seabirds, which often forage in remote oceanic areas. In this study, we aimed to characterize the trophic ecology of two highly pelagic seabird species, Wilson’s storm-petrel Oceanites oceanicus and Black-bellied storm-petrel Fregetta tropica, breeding sympatrically on King George Island, maritime Antarctica, using a combination of methods. Prey species, assayed via metabarcoding of faecal and regurgitate samples, were dominated by teleost fish, primarily lanternfish (Myctophidae), and zooplanktonic crustaceans, mainly krill (Euphausiidae), but also included other prey with lower frequencies of occurrence, such as salps and amphipods. We used carbon and nitrogen bulk stable isotopes and compound-specific isotope analyses of amino acids of blood samples to derive isotopic niches and trophic positions, showing that Black-bellied storm-petrels prey on a slightly higher trophic position than Wilson’s storm petrels(3.7 and 3.5, respectively). Combining results of stable isotope and molecular diet analysis, indicate a diet richer in fish for Black-bellied storm-petrels and thus a potential niche segregation not in regards of general prey spectrum but proportion of specific prey types (prey composition). Additionally, intraspecific segregation in prey spectrum was observed in Wilson’s storm-petrels concerning their breeding stage (incubation vs. chick-rearing), suggesting selective chick provisioning. Future studies should investigate a potential interspecific spatial segregation in foraging areas
Cosmological neutrino mass: a frequentist overview in light of DESI
No full textInternational audienceWe derive constraints on the neutrino mass using a variety of recent cosmological datasets, including DESI BAO, the full-shape analysis of the DESI matter power spectrum and the one-dimensional power spectrum of the Lyman- forest (P1D) from eBOSS quasars as well as the cosmic microwave background (CMB). The constraints are obtained in the frequentist formalism by constructing profile likelihoods and applying the Feldman-Cousins prescription to compute confidence intervals. This method avoids potential prior and volume effects that may arise in a comparable Bayesian analysis. Parabolic fits to the profiles allow one to distinguish changes in the upper limits from variations in the constraining power of the different data combinations. We find that all profiles in the CDM model are cut off by the bound, meaning that the corresponding parabolas reach their minimum in the unphysical sector. The most stringent 95% C.L. upper limit is obtained by the combination of DESI DR2 BAO, Planck PR4 and CMB lensing at 53 meV, below the minimum of 59 meV set by the normal ordering. Extending CDM to non-zero curvature and CDM relaxes the constraints past 59 meV again, but only CDM exhibits profiles with a minimum at a positive value. Using a combination of DESI DR1 full-shape, BBN and eBOSS Lyman- P1D, we successfully constrain the neutrino mass independently of the CMB. This combination yields meV (95% C.L.). The addition of DESI full-shape or Lyman- P1D to CMB and DESI BAO results in small but noticeable improvement of the constraining power of the data. Lyman- free-streaming measurements especially improve the constraint. Since they are based on eBOSS data, this sets a promising precedent for upcoming DESI data
The role of hydrogen sulfide and trisulfur radical ion in molybdenum transport by hydrothermal fluids: implications for porphyry-epithermal Cu-Au-Mo deposits
No full textInternational audienceKnowledge of the chemical speciation of molybdenum in fluids under hydrothermal conditions is key to understanding the formation of porphyry Cu-Au-Mo deposits, which are the primary economic source of copper, molybdenum and rhenium. However, the chemical identity and thermodynamic stability of aqueous complexes of molybdenum and the role of different ligands on Mo metal transport yet remain inconsistent and incomplete, in particular for sulfur-bearing fluids typical of such environments. We have experimentally studied the role of hydrogen sulfide (H 2 S and HS -) and the trisulfur radical ion (S 3 •-) in the transport of molybdenum by hydrothermal fluids at 300 °C and 500 bar as a function of pH, redox conditions as well as sulfur speciation and concentration. We combined solubility measurements of molybdenite in hydrothermal reactors using fluid quenching or sampling, with in situ synchrotron X-ray absorption spectroscopy experiments and thermodynamic and molecular modeling. Our solubility and spectroscopic dataset is consistent with the formation of the tetrathiomolybdate complex, MoS 4 2-, in reduced, H 2 S/HS --dominated fluids of neutralto-alkaline pH. In contrast, a mixed-ligand complex with three sulfide ions and one trisulfur radical ion, MoS 3 (S 3 ) -, prevails in more oxidized and more acidic fluids at the sulfide-sulfate transition where S 3 •-is far more abundant. In both complexes, Mo is nominally hexavalent and in a first-shell tetrahedral coordination with sulfur atoms. The derived equilibrium constants of the formal solubility reactions (log 10 K):MoS 2(s) + 2 H 2 S 0 (aq) + 0.5 O 2(g) = MoS 4 2-+ 2 H + + H 2 O (liq) and MoS 2(s) + H 2 S 0 (aq) + S 3 •-+ 0.5 O 2(g) = MoS 3 (S 3 ) -+ H 2 O (liq) , at 300 °C and 500 bar are 0.5±0.4 and 14.6±0.4, respectively. The solubility of MoS 2(s) predicted using these constants aligns well with Mo concentrations measured in natural fluid inclusions in quartz that record S-rich fluids from porphyry-epithermal systems. In contrast, other types of Mo complexes invoked so far (molybdates, alkali ion pairs, oxy-chlorides or oxysulfides) are negligible at such conditions. Thus, trisulfur radical ion complexes may be important carriers of Mo in hydrothermal fluids and would require further systematic investigation across a wide range of temperature and pressure.</p