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SLICE -- Combining Strong Lensing and X-ray in AC 114. Insights into the Merger Scenario
No full textInternational audienceAC114 is a historically significant galaxy cluster, being one of the first strong lensing clusters detected from the ground in the early 1990s, prior to the launch of the HST. Despite this early prominence, no detailed lensing analyses have been carried out for more than fifteen years. We here study this cluster using JWST imaging obtained as part of the SLICE program, complemented by archival HST and X-ray observations. JWST data reveal ten new multiply imaged systems and enable the identification of conjugate substructures in several of the sixteen systems, significantly increasing the number of strong lensing constraints. Using these data, we construct a parametric mass model with Lenstool and extend it by explicitly incorporating the Chandra data in a combined strong lensing+X-ray fit. Our best-fit model reproduces the multiple images with an RMS of 0.4" while simultaneously matching the X-ray data. The dark matter distribution is unimodal and centered on the brightest cluster galaxy, with a large core radius of 83+-5kpc, consistent with values reported in other strong lensing clusters. The strong lensing constraints require the inclusion of an external shear component which position angle points unambiguously towards a nearby (~1Mpc), well defined mass concentration at the same redshift in the North-West, for which we propose the naming AC114b. The spatial coverage of the XMM-Newton data encompasses the whole structure, allowing us to probe the X-ray properties of the companion cluster and the thermodynamics of AC114, providing evidence for a major merger, in line with previous signatures seen in Chandra, radio and optical spectroscopic data. Our results shed new light on the merging scenario, revealing a major merger caught in a late post-collisional phase, where AC114 is the dominant system and Ac114b has likely been stripped of its hot gas
Locating Centers of Clusters of Galaxies with Quadruple Images: Witt's Hyperbola and a New Figure of Merit
No full textInternational audienceFor any elliptical potential with an external parallel shear, Witt has proven that the gravitational center lies on a rectangular hyperbola derived from the image positions of a single quadruply lensed object. Moreover, it is predicted that for an isothermal elliptical potential the source position both lies on Witt's Hyperbola and coincides with the center of Wynne's Ellipse (fitted through the four images). Thus, by fitting Witt's Hyperbolae to several quartets of images - ten are known in Abell 1689 - the points of intersection provide an estimate for the center for the assumed isothermal elliptical potential. We introduce a new figure of merit defined by the offset of the center of Wynne's Ellipse from Witt's Hyperbola. This offset quantifies deviations from an ideal elliptical isothermal potential and serves as a discriminant to exclude poorly fitted quadruples and assign greater weight to intersections of hyperbolae of better fitting systems. Applying the method to 10 quads (after excluding 7 poorly fitted quads) in Abell 1689, we find the potential is centered within 11" of the BCG, X-ray center, flexion-based center and the center found from a total strong lensing analysis. The Wynne-Witt framework thus delivers a fast, analytic, and self-consistency-checked estimator for centers in clusters with multiple quads
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
Large-scale genome-wide association study of 398,238 women unveils seven novel loci associated with high-grade serous epithelial ovarian cancer risk
No full textInternational audienceABSTRACT Background Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of BRCA1 / BRCA2 (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS). Methods We analyzed >22 million variants for 398,238 women. Associations were assessed separately by consortium and meta-analysed. OCAC and CIMBA data were used to develop PGS which were trained on FinnGen data and validated in UKBB and BioBank Japan Results Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was finding that TP53 3’-UTR SNP rs78378222 was associated with HGSOC (per T allele relative risk (RR)=1.44, 95%CI:1.28-1.62, P=1.76×10 -9 ). The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95%CI:1.37-1.54) per standard deviation in the UKBB validation (AUROC curve=0.61, 95%CI:0.59-0.62). Conclusions This study represents the largest GWAS for HGSOC to date. The results highlight that improvements in imputation reference panels and increased sample sizes can identify HGSOC associated variants that previously went undetected, resulting in improved PGS. The use of updated PGS in cancer risk prediction algorithms will then improve personalized risk prediction for HGSOC
Measuring cosmic dipole with the GRB luminosity-time relation
No full textInternational audienceWe present a new analysis of cosmic dipole anisotropy using gamma-ray bursts (GRBs) as high-redshift standardizable candles. GRBs are ideal probes for testing the cosmological principle thanks to their high luminosity, wide redshift range, and nearly isotropic sky coverage. For the first time, we employ the luminosity-time (L-T) relation, known in the literature as the bidimensional X-ray Dainotti relation, corrected for redshift evolution, to standardize a sample of 176 long GRBs detected by \textit{Swift}. We test for dipolar modulations in the GRB Hubble diagram using both the Dipole Fit Method and a new approach introduced here, the Anisotropic Residual Analysis Method. Both methods yield consistent results: a dipole amplitude of pointing towards (RA, DEC) (equatorial coordinates). As shown in the Appendix, this corresponds to a boost velocity of the observer with respect to the GRB rest-frame in the antipodal direction from the dipole direction. Extensive isotropy tests and 20,000 Monte Carlo simulations confirm that the detected signal cannot be explained by chance alignments or by the angular distribution of the GRB sample. We also show how, by incorporating a dipole term, residual correlations are eliminated, showing that the dipole model provides a better fit than standard isotropic CDM
Biofouling in milli-labyrinth channels of drip irrigation systems using reclaimed wastewater: A review of optical methods and numerical modelling
No full textInternational audienceDrip irrigation systems are known for their high water-use efficiency due to the combination of using milli-labyrinth channels to optimise flow distribution and reusing reclaimed wastewater. However, clogging andbiofouling remain significant challenges that affect system performance and lifespan. This review provides acomprehensive overview of biofouling in drip irrigation systems, with a focus on how hydrodynamic conditionsand nutrient availability in reclaimed wastewater influence the attachment, growth, detachment, and decayof biofilm. The ability of advanced optical techniques, including particle tracking velocimetry, industrialcomputed tomography, and optical coherence tomography to visualise, measure, and analyse biofoulingprocesses in drip irrigation systems is discussed, along with their strengths and limitations. Additionally, theability of current biofilm modelling approaches, including both continuum and discrete methods, to simulatenutrient transport, microbial activity, and biofilm–fluid interactions are discussed. By combining insights fromexperimental data and computational models, this review also identifies key research gaps and presents a newframework for applying biofilm modelling to drip irrigation systems. Future research directions are suggestedto improve our understanding of drip irrigation biofouling and to predict it, to optimise emitter design, andincrease the overall reliability and sustainability of drip irrigation system
Assessing the persistence of semi-natural species-rich grasslands under changes in grazing practices: Insights for grassland restoration
No full textInternational audienceGrazing practices are well-known to shape plant populations and communities in semi-natural grasslands and the conservation and restoration of these ecosystems relies heavily on maintaining traditional extensive grazing systems, which have persisted for centuries or even millennia. However the changes of grazing practices in relation to climate change and socio-economic factors can result in biodiversity loss, shifts in vegetation composition, soil degradation, and declines in ecosystem services and habitat quality. This study aimed to understand the medium-term (3-16 years) effects of changes in grazing practices by comparing two sheep grazing methods in semi-natural rangelands of Southern France: millennia-old traditional herding with shepherds and herding dogs, and the recent practice of fenced free grazing, which emerged at the beginning of the 21st century. Surveys were conducted at six paired study sites over three years, assessing vegetation, mesological data, and plant traits. While the five vegetation zones created by traditional herding remain identifiable, the transition to fenced grazing has induced, for the first time in these grasslands, a mid-term homogenization of plant communities, marked by the spread of xero-mesophilous species and the disappearance of the historical grazingintensity gradient. These findings highlight the ecological implications of altered grazing regimes, such as fenced grazing, for biodiversity conservation of rangelands with millennia-long grazing history, ecosystem functionality, and long-term persistence of high heritage value grasslands. They provide critical insights into designing adaptive and sustainable restoration strategies for degraded grasslands under changing environmental and socio-economic conditions
Evaluating solid-state neutron detectors for measuring 14 MeV neutrons at high temperatures
No full textInternational audienceSilicon Carbide 4H Polytype (4H-SiC) and Diamond wide bandgap semiconductors are promising detector materials for fusion environments. Threshold energy nuclear reactions provide information on the energy of impinging fast neutrons and the combination of low intrinsic carrier concentration with high thermal conductivity makes these semiconductors suitable for high-temperature applications, especially for neutron monitoring in tritium production through ITER breeding blankets. While the carrier properties of SiC and Diamond offer interesting charge collection dynamics from room temperature up to 200 °C, the stability of their detection performance at high temperatures above 200 °C remains to be confirmed. To investigate this, we conducted a measurement campaign in a fast neutron field representative of fusion reactors at the GENESIS (Generator of Neutrons for Science and IrradiationS) research platform of LPSC (Laboratoire de Physique Subatomique et de Cosmologie) laboratory in Grenoble, France. Both 4H-SiC and Diamond sensors were irradiated with 14 MeV fast neutrons from a D-T neutron generator while encapsulated in a heating device, recording current signals from room temperature up to 500 °C. Using a direct measurement method of charge carrier collection dynamics as a function of applied bias voltage and temperature by pulse shape analysis provided information on velocity drift and collected charge. The results offer a first representative study of charge carrier mobility behavior with increasing temperature up to 500 °C. The stability of performance in terms of CCE (charge collection efficiency) has been demonstrated for SiC from room temperature up to 500 °C, while Diamond experiences a CCE drop of 60% between 200 °C and 300 °C
Pottery chaînes opératoires at Incoronata. Local/regional production and imports (9th to 7th centuries BC)
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La représentation du végétal dans le cinéma documentaire autochtone.
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