Ven 10 Dec 14H00 Durée - 01H00

Online (,

Search for an Anomalous Excess in Neutrino-Induced Interactions in the MicroBooNE Liquid Argon Time Projection Chamber

The MicroBooNE experiment was designed primarily to explore the nature of the previously observed low-energy excess in electron neutrino candidates in the MiniBooNE experiment located in the Booster Neutrino Beamline at Fermi National Accelerator Laboratory. Using an 85-ton active volume Liquid Argon Time Projection Chamber (LArTPC) with its excellent electron versus photon separation capability, the MicroBooNE experiment searches for an anomalous excess with an electromagnetic signature in several neutrino-induced interaction channels. In this talk, I will report the latest search results based on data taken from February 2016 to July 2018 in several exclusive and inclusive charged-current electron neutrino-induced interaction channels as well as a neutral-current Δ radiative decay channel.

Qian Xin | Brookhaven National Lab

Ven 03 Dec 14H00 Durée - 01H00

Amphi Dirac,

Galaxy Cluster Cosmology: Understanding systematic effects with multi-wavelength observations at high-angular resolution

Upcoming cosmological surveys such as Euclid, LSST, and CMB-S4 will have both the sensitivity and the area to push cluster detection to z > 2. The resulting cluster catalogs will contain of the order of 100,000 detections, which is two orders of magnitudes more than the number of clusters detected by the Planck satellite. As the largest gravitationally bound systems in the universe, galaxy clusters provide a low-redshift cosmological probe that is complementary to BAO, SN Ia, and CMB. Thus, it will be essential to use these objects to alleviate inherent degeneracies between cosmological parameters estimated with each individual probe, to minimise the impact of systematic effects, and to unveil potential new tensions with the standard cosmological model that are hitherto not significant. This will only be feasible if all sources of systematic uncertainties associated with cluster cosmological constraints are characterized in details. In particular, the mass-observable scaling relation, that links the observable considered in a given survey to the total mass of galaxy clusters, as well as the halo mass function, that traces the abundance of halos as a function of mass and redshift, are both key ingredients driving the precision and accuracy of the final cosmological contours. High-angular resolution millimetre and X-ray follow-up studies of clusters detected in cosmological surveys enable investigating the Intra-Cluster Medium (ICM) properties at high redshift and greatly improve our understanding of cluster formation. Such studies are fundamental to precisely calibrate the mass-observable scaling relation and the sub-grid models considered in the numerical simulations that infer the halo mass function. I will present results obtained in the context of the NIKA2 galaxy cluster program aiming at calibrating the mass-observable scaling relation at high redshift for future millimetre surveys such as CMB-S4. I will then highlight the importance of observational contraints from cluster analyses at high redshift in order to calibrate ICM models in numerical simulations. To this end, I will describe recent results from two on-going programs realised within the South Pole Telescope and MaDCoWS collaborations.

Ruppin Florian | IP2I

Florian Ruppin a réalisé un doctorat au LPSC (Grenoble) au sein de la collaboration internationale NIKA2 de 2015 à 2018. Durant cette période, ses activités se sont inscrites dans la thématique de la cosmologie via l’observation d’amas de galaxies par effet Sunyaev-Zel’dovich (SZ). Elles ont porté sur des sujets allant des observations SZ effectuées avec la caméra NIKA2 installée au télescope de 30 mètres de l’Institut de Radioastronomie Millimétrique (IRAM) jusqu’à l’estimation des paramètres cosmologiques Planck en passant par l’analyse des données brutes de NIKA2 et des cartes SZ réalisées. Il a ensuite effectué un post-doctorat de trois ans au Massachusetts Institute of Technology (MIT) et a rejoint les collaborations South Pole Telescope (SPT) et MaDCoWS. Ses travaux au MIT ont permis d’estimer les effets systématiques affectant les contraintes cosmologiques issues de l’analyse de catalogues d’amas de galaxies via une combinaison des données X mesurées par le satellite Chandra, des données optique/IR du satellite Spitzer, des données SZ mesurées par SPT, NIKA2 et MUSTANG-2 et des données radio obtenues par ATCA. Il est membre du core-team NIKA2, membre du comité d’allocation du temps du satellite Chandra et responsable scientifique (PI) de plusieurs programmes d’observation à l’IRAM et à la NASA. Il a rejoint l’IP2I en septembre 2021 afin d’apporter son expertise au sein de la collaboration Euclid. Son objectif est d’étudier les modèles de gravitation modifiée via la combinaison des amas de galaxies et des distorsions espace-redshift détectés par Euclid.