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Spectroscopic characterization of a remarkable temporally varying, triple-lensed quasar at z=2.67
No full textInternational audienceGravitationally lensed quasars are viable cosmic tools for constraining a diversity of fundamental astrophysical phenomena; They enable identification of faint, low-mass supermassive black holes, provide unique constraints on the intervening intergalactic or interstellar medium in their sightlines, and can be used to determine key cosmological quantities such as the Hubble constant, . However, they are rare phenomena, and it has proven difficult to define efficient, unbiased selection methods. In this study, we report the independent spectroscopic identification of a remarkable triple-lensed quasar at , identified based on astrometric measurements from the {\em Gaia} mission, previously identified in Pan-STARRS. Furthermore, a larger spectroscopic follow-up survey of {\em Gaia}-detected candidate lensed quasars. We characterize in detail the three mirror images of the quasar and their spatial and temporal spectroscopic coverage, with focus on the emission-line properties which shows variation across sigthlines and temporal evolution over the months spectroscopic campaign. We construct a lens model of the foreground source from a combination of the multiple spectra and deep optical imaging, providing a robust halo mass of . Based on the lens model, the time delay between each sightline is translated into an intrinsic quasar time, allowing us to construct a quasar timeseries over months with monthly cadence. Over months timescales the broad emission lines vary in both velocity offset and equivalent width (EW) as well as an overall increase in ionization. This exemplary triple-lensed quasars demonstrates the viability of identifying such rare lens configurations based purely on the astrometric measurements from the {\em Gaia} mission, which we here provide optimized selection criteria for, for future studies
On the space of subgroups of Baumslag-Solitar groups II : High transitivity
No full textA continuation of "On the space of subgroups of Baumslag-Solitar groups I: perfect kernel and phenotype", by Alessandro Carderi, Damien Gaboriau, François Le Maîitre, Yves Stalder (hal-03829832). 44 pages, 1 figureInternational audienceWe continue our study of the perfect kernel of the space of transitive actions of Baumslag-Solitar groups by investigating high transitivity. We show that actions of finite phenotype are never highly transitive, except when the phenotype is 1, in which case high transitivity is actually generic. In infinite phenotype, high transitivity is generic, except when |m|=|n| where it is empty. We also reinforce the dynamical properties of the action by conjugation on the perfect kernel that we had established in our first paper, replacing topological transitivity by high topological transitivity
La critique de la doctrine de l'État chrétien chez Ernst-Wolgang Böckenförde
No full textInternational audienceFervent catholique mais aussi grand défenseur de l'État, le juriste allemand Ernst-Wolgang Böckenförde a développé une importante réflexion sur les rapports entre politique et religion à l'heure de leur réarticulation dans le contexte moderne de la sécularisation. Conscient de l'extrême fragilité de l'État sécularisé, il appelle l'Église à se réconcilier avec son ancien adversaire. En retour, la religion doit se voir reconna\ⁱtre dans son rôle de la régulation de la liberté et de structuration de la société
Overexpression of the maize 9-lipoxygenase gene ZmLOX4 confers resistance to Fusarium verticillioides via the oxylipin and jasmonic acid-mediated pathways
No full textInternational audienceAbstract Fusarium verticillioides is a prominent pathogen in cereals that reduces crop yields and poses a threat to food safety by producing the secondary metabolites fumonisins. Maize lipoxygenases (ZmLOXs) genes are involved in the biosynthesis of oxylipins that function as signals in regulating defense. Previously, we showed that ZmLOX4 gene mutagenesis was associated with susceptibility to F. verticillioides in kernels, seedlings and ears altering ZmLOX transcript profiles as well as LOX enzymatic activity. In the current study, we show that ZmLOX4 overexpression results in enhanced pathogen and fumonisin contamination resistance, substantiating its role in defense and making ZmLOX4 a good target to confer disease resistance. Transcriptomic and lipidomic analyses reveal that ZmLOX4 overexpression up-regulates 9-LOX gene expression and boosts the 9-oxylipin production under fungal infection. The increased expression of jasmonic acid-related genes is also observed, but is reinforced when ZmLOX4 is overexpressed, correlating with wider accumulation of jasmonic acid-related metabolites. The ZmLOX4 gene has potential applications in engineering cropping plants to increase immunity to F. verticillioides
Holocene climatic changes in the Kerguelen archipelago (South Indian Ocean) based on marine and lacustrine palaeoclimatic archives
No full textInternational audienceClimatic variability in the Southern Hemisphere is largely controlled by the latitudinal position of the Southern Hemisphere Westerly Winds (SHW), whose migration influences precipitation, temperature, and Antarctic upwelling. This study presents the results of analyses of two lacustrine sediment cores from Lake Armor, located on the subantarctic Kerguelen Islands (49 • 15′S, 69 • 10′E), within the SHW belt. Lipid biomarkers (Glycerol Dialkyl Glycerol Tetraethers, n-alkanes, and their hydrogen isotopes) were used to reconstruct mean annual air temperature above freezing (MAF) and humidity conditions. These records are compared with a high-resolution diatom-based summer sea surface temperature (SST) reconstruction from marine core MD11-3353, situated 150 km southwest of Lake Armor. In the late glacial and Early Holocene, our results reveal a period of warm air temperature, comparable to current values and very warm sea surface temperature, 5°C above the current values. Around 9000 cal a BP, an abrupt transition occurred, marked by a cooling of 5°C in SST and 1.5°C in MAF, interpreted as a northward migration of the SHW and associated oceanic fronts. The Mid-to-Late Holocene period is characterized by pronounced MAF variability, including a notably warm interval between 3000 and 2000 cal a BP, when n-alkane dD suggests the prevalence of wetter conditions. Since ~250 cal a BP, a southward migration of the SHW has produced a 2.5°C rise in MAF. Our findings are overall consistent with previous studies from the Indian Ocean, but permit us to go a step further as by comparing SSTs and air temperatures. This suggests that SST is not a reliable predictor of air temperature on the Kerguelen Islands, particularly during the Early Holocene. We hence argue that Kerguelen air temperature is predominantly controlled by the position of westerly winds, as an indicator of reorganisations in air mass trajectories
The Caravan Roads and Way Stations in North-West Arabia (CaRoWS) Project. Report on the 2025 Season.
No full textThis is the report of the 2025 fieldwork season undertaken by the CaRoWS project in the Saudi Arabian Ḥismā. It contains several chapters : on the Greek, Early Islamic, Ancient North Arabian and Nabataean as well Developing Arabic inscriptions. They are preceded by an introduction and followed by a general commentary. It contains also appendices, among which maps, a list of sites and a catalogue of the new Nabataean and Nabataeo-Arabic inscriptions. 33 plates illustrate the report.Ceci est le rapport de la campagne 2025 du projet CaRoWS dans la Ḥismā saoudienne. Il comprend plusieurs chapitres consacrés aux inscriptions grecques, arabes, nord-arabiques anciennes, nabatéennes et nabatéo-arabes. Il comprend également une introduction et un commentaire général.Le rapport contient aussi des annexes, parmi lesquelles des cartes, une liste des sites et un catalogue des nouvelles inscriptions nabatéennes et nabatéo-arabes. L'ensemble est par ailleurs illustré de 33 planches
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
Tacq -Context Aware Tactic Recommendation for Rocq
No full textInternational audienceDespite recent impressive achievements of Large Language Models (LLMs) in formal mathematics using proof assistants, the state-of-the-art has mostly focused on mathematics competitions where problems typically involve simple and well-understood concepts. This is unfortunately far from current practice in formal mathematics, where experts must navigate large libraries of lemmas and manipulate complex constructions.In this paper, we focus on the problem of next tactic recommendation for Rocq. A key issue is to prompt the model with enough context to understand the current goal when the proof relies on large libraries with numerous dependencies and where specialized notations are pervasive. We present a tool that can extract notations and dependencies from the current goal and annotate them with natural language docstrings. We show that such augmented contexts improve the ability of state-of-the-art models to generate valid tactics on the challenging MathComp library.</p