Recent Talks

List of all the talks in the archive, sorted by date.


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Friday April 19, 2024
Enol Matilla Blanco
IAC

Abstract

Diseño, construcción y primera luz del EMO-1, un observatorio casero con estación meteorológica integrada, monitoreo permanente del cielo y colaboración científica.

 

Youtube:
https://youtube.com/live/0PFICuLjOAE?feature=share


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Friday April 5, 2024
Pavel Nichita

Abstract

En esta charla se va a presentar los telescopios ATLAS y su integración en la red ATLAS dirigida por la Universidad de Hawaii. Vamos a hablar del estado actual del proyecto, tecnología que se utiliza en los telescopios y el stack software que lleva asociado.


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Friday March 8, 2024
Marcos Reyes García Talavera
IAC

Abstract

El objetivo de esta charla es presentar los recientes avances del sistema de Óptica Adaptativa de GTC (GTCAO). Se resumirán los resultados de las pruebas de aceptación en la sala AIV en abril de 2023; las dificultades y el éxito del transporte al ORM y la instalación en GTC en junio de 2023; la integración del sistema con el control del telescopio y los primeros resultados de las campañas de commissioning en cielo. Se repasará también brevemente el estado del resto de proyectos del programa, en concreto el sistema de Estrella Guía Láser y el instrumento GRANCAIN.


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Thursday February 1, 2024
Prof. Raul Abramo
USP

Abstract

 

Cosmology today is facing two fundamental problems: we do not know for certain what is the present expansion rate of the Universe, or why that expansion seems to be accelerating. In order to address these challenges, new telescopes and instruments are becoming available. One of these instruments is J-PAS, which at the end of 2023 started to map the Universe using 56 narrow optical bands, detecting $\sim 4. \times 10^4$ extragalactic objects in each square degree. Massive new data sets such as J-PAS can be quite challenging to digest, and Machine Learning (ML) has become central in our efforts to detect, classify and to extract properties of astrophysical sources. I will discuss how ML has allowed us to advance in source classification, determining which ones are stars, galaxies or quasars, paving the way for J-PAS to become one of the most complete galaxy surveys at $z \lesssim 1$, and the best quasar survey at $z \lesssim 4$. I will also show that, on the theoretical side, numerical simulations together with ML techniques have allowed us to reproduce the intricate relationships between halos and galaxies with unprecedented accuracy, which is what will ensure that we can realize the potential of these amazing new observations in terms of a new understanding about the evolution of our Universe.
ID: 949 0702 9675
Password:  254951

 


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Tuesday January 23, 2024
Dr. José Antonio de Diego Onsurbe
jdo@astro.unam.mx

Abstract

Using unsupervised machine learning methods, we present a novel approach to classifying galaxies into early and late types based on their spectral characteristics. The research utilizes a balanced dataset of 2000 galaxies from the Galaxy Zoo 2 and spectral data from the Sloan Digital Sky Survey Data Release 13. The methodology involves applying an Autoencoder Neural Network for dimensionality reduction, followed by a Gaussian Mixture Model for clustering. The study demonstrates that this approach achieves an accuracy rate of approximately 86% in galaxy classification, highlighting the potential of unsupervised machine learning techniques in enhancing the precision and efficiency of morphological classification of galaxies based on spectral data.

 


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Thursday December 14, 2023
Dr. Marina Trevisan
Universidad Federal Rio Grande do Sul, Brasil

Abstract

In the local Universe, there are a handful of dwarf star-forming galaxies that are young, having formed a large fraction of their stellar mass during their last few hundred Myr. However, little is known about the fraction of young stellar populations in more massive galaxies. Using the data from the Sloan Digital Sky Survey, we identified a surprisingly large sample of more massive, very young galaxies (VYGs), defined to have formed at least 50 per cent of their stellar mass within the last 1 Gyr. In this seminar, I will present our study on the fractions, properties and environment of low-redshift VYGs in observations and simulations, discuss possible mechanisms responsible for the recent triggering of intense star formation activity in these systems, and argue that VYGs can be useful in constraining the uncertainties in both galaxy formation models and spectral modelling of galaxy star formation histories.


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Thursday November 30, 2023
Dr. Amin Babazabeh
University of Vienna

Abstract

"God does not play dice.", this is the famous quoted by Einstein who believed that quantum mechanics is not complete and could not possibly explain everything about
nature. However, in 2022, John F. Clauser, Alain Aspect, and Anton Zeilinger were jointly awarded the Nobel Prize in Physics for their groundbreaking experimental proof of
Bell's inequality, effectively demonstrating entanglement as a defining characteristic of quantum mechanics. However, some assumptions have been considered to experimentally
verify the Bell’s Inequality which is known as loopholes. One of which is the 'freedom of choice' loophole, questions the absence of statistical correlations between measurement
settings and external factors influencing the outcomes. In this presentation, I will delve into some work of Prof. Zeilinger's research group, which culminated in their prestigious
Nobel Prize and were performed at La Palma and Tenerife Islands. Moreover, I will talk on their recently pioneering use of distant astronomical sources as 'cosmic setting
generators'. This innovative approach allowed us to reach back in time, extending our understanding to approximately 7.8 billion years ago the most recent period beyond
which any local-realist influences could manipulate the 'freedom-of-choice' loophole and impact the observed Bell violations. Furthermore, the exciting prospects of identifying
potential sources that could extend this temporal boundary even further will be explored.

 

 


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Friday November 24, 2023
Dr. Mahy Soler
IAC

Abstract

El Telescopio Solar Europeo (EST) se construirá en el Observatorio del Roque de los Muchachos, un lugar conocido por sus excelentes condiciones de observación. El propio diseño de EST puede influir en estas condiciones y afectar a su calidad óptica en un efecto denominado ‘seeing’ local. La Oficina de Proyecto de EST ha implementado una nueva metodología para estimar el ‘seeing’ local combinando análisis térmicos, de dinámica de fluidos y ópticos. En esta presentación se expondrá esta metodología y su aplicación en criterios de diseño. 

Youtube: https://www.youtube.com/watch?v=h76KS893uY4


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Thursday November 23, 2023
Piyush Sharda
Oort Fellow and IAU Gruber Foundation Fellow, Leiden Observatory, Leiden University, The Netherlands

Abstract

From the time the first stars formed to the present-day, metals have witnessed the assembly of structure in the Universe in great detail. Although metals only form in stars and stellar remnants, they are ubiquitously present everywhere. However, we still do not understand how metals are effectively dispersed throughout the Universe, and the various roles they play in shaping galaxies. In this talk, I will present a multi scale approach to study the role of metals in galaxy evolution, from molecular clouds to galactic discs. On smaller scales, I will focus on physical processes that shape up the initial mass function (IMF, with a particular emphasis on metal-free and metal-poor environments) that directly set the integrated yield of metals in the first and early galaxies. I will discuss results from high resolution radiation chemo-magnetohydrodynamic simulations that study the impact of turbulence, radiation feedback and magnetic fields on the primordial IMF, and describe analytical models of dusty molecular clouds that explain the transition in the IMF as the metal abundance grows over cosmic time. On larger scales, the talk will cover the physics of gas-phase metal distribution in galaxies. Using a combination of spatially-resolved gas-phase metallicity measurements and novel semi-analytical models, I will present recent results that advance our understanding of metallicity gradients in (late type) galaxies. In particular, I will show how self-consistently incorporating metal dynamics into galaxy evolution models is key to explaining the observed trends in metallicity gradients with galaxy mass, metallicity, and kinematics. I will end by highlighting how ongoing/upcoming astronomical facilities will transform our understanding of metal evolution in galaxies.


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Tuesday November 21, 2023
Dr. Sofia Gallego
Astroparticle and Cosmology Laboratory (Paris)

Abstract

Galaxies are embedded within a network of interconnected filaments, essential for their formation and growth. Simultaneously, they emit radiation and enriched matter back into their environment, influencing the evolution of the cosmic gas. Recent advancements in wide-field spectrographs offer a unique perspective, allowing us to probe the spatial distribution and properties of the circumgalactic medium at high redshift, particularly the Lyman-alpha line emitted by cold hydrogen gas. These insights are especially valuable in overdense regions, like protoclusters and groups, where we can explore most of the physical mechanisms at play. By combining data from instruments such as KCWI, MOSFIRE, IRAC, LRIS, and HST, we aim to decipher the various mechanisms that steer the evolution of galaxies and protocluster environments around the Cosmic Noon epoch, unveiling how mergers, AGN feedback, and galactic outflows influence both the large-scale gas distribution and the general properties of the galaxies themselves. Nonetheless, several degeneracies persist among the observed properties of the gas and the potential physical mechanisms responsible, underscoring the necessity for improved models of these cosmic phenomena and a larger statistical sample of protocluster environments.