The James Webb Space Telescope (JWST) is revolutionizing our understanding of galaxy formation and evolution in the early Universe. In this seminar, I will discuss how JWST has reshaped our view of the first billion years of cosmic history, from the emergence of the earliest galaxies to their role in cosmic reionization. In particular, I will highlight the crucial contribution of large-area surveys like COSMOS-Web in detecting rare and distant objects, mitigating cosmic variance, and establishing connections between galaxy properties and their environment. Finally, I will provide an overview of the latest insights enabled by JWST in the COSMOS field.
GECO
LAM seminar: Raphaël Mignon-Risse – Supermassive binary black holes
Despite the re-birth of multi-messenger astronomy, no unambiguous electromagnetic (EM) counterpart to stellar-mass binary black hole (BBH) pre-/post-merger has been reported. In 2035+, LISA will be launched and will detect the gravitational waves from supermassive BBHs, expected to be gas-rich and therefore EM-loud — and even multi-messenger — systems. Detecting the EM pre-merger counterpart (e.g. with NewAthena in X-rays, V. Rubin Observatory in optical) would allow for optimal follow-up, while an EM-GW detection would be precious for several fundamental questions of astrophysics or cosmology. However, uncertainties remain: on the one hand, no supermassive BBH detection has been confirmed yet, despite a growing list of candidates. On the other hand, the accretion properties onto supermassive BBHs and their EM signatures are not firmly identified because few numerical codes are able to model accretion and emission around BBHs in General Relativity (GR).
After an introductory part, I will present e-NOVAs (“extended Numerical Observatory for Violent Accreting systems”), the first European GR magneto-hydrodynamical+GR ray-tracing code incorporating an analytical BBH spacetime. I will show the latest results obtained with e-NOVAs (and comparable tools worldwide) to understand the BBH circumbinary flow evolution and the multi-wavelength observables that derive from it. Those are the signatures we are looking for to detect, for the first time, and from now on, supermassive BBHs.
LAM seminar by Salvatore Capozziello – Going beyond the standard LCDM model by Cosmography
The standard cosmological model is recently suffering severe shortcomings and tensions due to the fact that, very likely, it has to be improved at IR and UV scales. In view to reconstruct a self-consistent cosmic history, cosmography revealed a model-independent approach capable of fixing reliable models starting from observations.
Without claim to completeness, we are going to sketch an overview of the method and the possible realizations towards the solutions of various cosmological tensions.
Cancelled LAM seminar: Elena Sellentin
Seminar is cancelled for personal reasons
Grand Public seminar: Christophe Adami
This seminar will give an overview of the current and future state of the Observatoire de Haute Provence.
LAM seminar: Yaël Nazé – The mysterious gamma Cas stars
Long thought to be a prototype of Be stars, the first detected case of such objects, gamma Cas, was found to be actually atypical amongst them!
Indeed, it emits very bright and extremely hard X-rays with a luminosity intermediate between that of normal massive stars and that of high-mass X-ray binaries. Recent efforts in X-ray monitorings have revealed that such objects are not uncommon hence gamma Cas stars are important ionizing sources, particularly at low metallicities where Be stars abound. The properties of these stars will be reviewed using the latest observational results.
