Date: October 17 2024
Venue: Auditorio del IAFE, Instituto de Astronomía y Física del Espacio (CONICET-UBA). Pabellón IAFE, Ciudad Universitaria, CABA - Argentina.
PROGRAM
10:00-11:00hs: Dra. María Emilia De Rossi (IAFE)
Title: “Signals from the first galaxies in the far infrared and submillimeter bands”
Abstract:
With the advent of the James Webb Space Telescope (JWST), we are rapidly expanding the frontiers of what we knew about the early stages of the Universe and, especially, about the first galaxies. In this talk, I will present the results of a project aimed at studying the nature of primeval galaxies from the radiation generated by their cosmic dust content. With this purpose, we implemented a model of primordial dust emission. The radiation emitted by primordial dust is expected to be observable in the far infrared (FIR) and submillimeter (sub-mm) bands, so the results of this project could contribute to the synergy between JWST and other facilities that cover such observational wavelengths. I will share the results of different works that we carried out in recent years. I will focus mainly on the study of the infrared emission from sources that are candidates for primeval massive galaxies, similar to those detected by the JWST at z ≳ 10
11:00-11:30hs: Intervalo de café
11:30-12:30hs: Valentina Crespi (IALP)
Title: “Fermionic Dark Matter Spikes around Supermassive Black Holes”
Abstract:
Over the last years it has been established that dark matter (DM) rearranges around a compact object, forming an over-density (spike). In particular, for Supermassive Black Holes (SMBH), some questions that are still open are for example, What is the initial mass of the SMBH seed and its origin? What consequences do spikes imply for other objects in their vicinity? How do these configurations arise in a cosmological framework? We focus on the profiles obtained when a galactic DM halo is modeled by fermionic particles described according to the Ruffini-Arguelles-Rueda (RAR) model. Two interpretations for the origin and evolution of the SMBH seed are possible within this DM model. One of baryonic origin, and the other due to the gravitational collapse of a DM core at the center of the halo. We find that the morphology of the spikes strongly depends on the nature of the DM particles and their physical regime. It is of interest to know how the DM distributes at galactic centers, as it allows to place bounds on the mass of the DM particle with different astrophysical probes. Some of these are stellar dynamics in galactic centers, detection of Gravitational Waves and the effect of dynamic friction in compact binaries.
12:30-14:00hs: Almuerzo
14:00-15:00hs: Dr. Gabriel León (FCAGLP)
Title: “Inflation without inflaton in unimodular gravity”
Abstract:
In this talk, we will present a mechanism for generating an inflationary phase without resorting to any type of scalar field(s). Instead, this early accelerated expansion is driven exclusively by a dynamical "cosmological constant" within the framework of unimodular gravity (UG), which is an alternative theory to GR. Due to the structure of the theory, UG admits a diffusion term that characterizes a possible non-conservation of the canonical energy–momentum tensor locally. Employing this feature of UG, we will show how to construct an inflationary phase that can be contrasted with current observations.
15:00-15:30hs: Intervalo de café
15:30-16:30hs: Daniel Supanitsky (ITeDA)
Title: "The highlights of the Pierre Auger Observatory"
Abstract:
The Pierre Auger Observatory is the largest cosmic ray detector in the world. It covers an area of 3000 km² and is located in Malargüe, Mendoza Province. Cosmic rays generate cascades of particles when they interact with atmospheric molecules, which are detected with surface detectors and fluorescence telescopes. The surface detector is composed of 1660 Cherenkov effect detectors distributed in a hexagonal grid. On the periphery of the surface array there are 27 fluorescence telescopes arranged in 4 sites that overlook the atmosphere above the surface array. The detection system is hybrid, the Observatory is able to observe the same atmospheric shower through the two detection systems mentioned before. The first phase of data collection of the Observatory, called Phase I, started in 2004 and ended in 2021. In this contribution, I will present the most important results of this phase, which include the measurement of the energy spectrum, the determination of the chemical composition of the primary, and the measurement of the distribution of cosmic ray arrival directions. The Pierre Auger Observatory is currently undergoing an upgrade that involves the installation of new detection systems and enhancements to various detector components. This initiative, named AugerPrime, is anticipated to be completed by the end of 2024. In this presentation, I will also outline the Observatory's future plans, which are rooted in AugerPrime.