Recent Talks

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


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Friday March 3, 2023
Adrián Calzadilla González
IAC

Abstract

La finalidad del proyecto TTNN es realizar la mejora del sistema de control de los telescopios IAC-80 y Carlos Sánchez con el objetivo que el nuevo entorno de software y hardware que se diseñe sea robusto
versátil, permitan controlar los telescopios de forma remota y facilitar, a posteriori, su operación automática. Para el cumplimiento de estos requerimientos en la parte software se está diseñando e implementando un sistema de control de alto nivel basado en ROS y una aplicación de escritorio escrita en pyQt5.

YouTube

https://www.youtube.com/watch?v=mbxU7VZzR8k&t=4s


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Thursday March 2, 2023
Dr. Carlo Cannarozzo
UNAM

Abstract

 

Early-type galaxies: instructions to build them through mergers
Massive early-type galaxies (ETGs) are "red and dead" systems mainly composed of old and metal-rich stellar populations. In a cosmological context, present-day ETGs are believed to be the remnants of a complex stellar mass assembly history marked by several mergers, which are the consequence of the underlying hierarchical assembly of their host dark matter halos. In this talk, I will deal mainly with the merger-driven evolution of ETGs. Firstly, I will illustrate a comparison between observed ETGs from the MaNGA survey and simulated galaxies from the IllustrisTNG cosmological simulation suite. The aim of this study is to provide an interpretative scenario of the stellar mass assembly history of observed present-day ETGs, comparing the radial distributions of their stellar properties with those of simulated galaxies, in which it is possible to disentangle the contribution of stars formed in situ (i.e. within the main progenitor galaxy) and stars formed ex situ (i.e. in other galaxies) and then accreted through mergers. Then, I will describe how the scaling relation between the stellar mass and stellar velocity dispersion in ETGs evolves across cosmic time. Specifically, by extending the results of Cannnarozzo, Sonnenfeld & Nipoti (2020), I model the aforementioned relation through a Bayesian hierarchical approach, considering ETGs with log(M∗/M⊙) > 9 over the redshift range 0 ≲ z ≲ 4. Together with a new characterisation of the relation, I reconstruct the back-in-time evolutionary pathways of individual ETGs on the stellar mass-velocity dispersion plane to answer the question “how did high-redshift ETGs assemble through cosmic time to reach the functional form of the relation in the present-day Universe?“.
After the main topic, if time permits, I would like to spend a few minutes presenting another extra content (below you can find the title and a brief abstract of this further content). Feel free to include it or not in the announcement mail.
EXTRA - Inferring the Dark Matter halo mass in galaxies from other observables with Machine Learning
In the context of the galaxy-halo connection, it is widely known that the Dark Matter (DM) halos show correlations with some physical properties of the hosted galaxy: the most well-known relation is the so-called Stellar-to-Halo-Mass Relation. However, we know that there are several other empirical relations among galaxy properties, involving, for example, the stellar mass, the gas and stellar metallicities, the black hole mass, etc. Given the complexity of the problem and the high number of galaxy properties that might be related to DM halos, the study of the galaxy-halo connection can be approached by relying on machine learning techniques to shed light on this intricate network of relations. With the aim of inferring the DM halo mass and then finding a unique functional form able to link the halo mass to other observables in real galaxies, I rely on the state-of-the-art Explainable Boosting Machine, a novel implementation of generalised additive models with pairwise interactions, training a model on the IllustrisTNG simulation suite at different redshift.

 

 

 

Youtube933518


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Tuesday February 28, 2023
Dr. David Jones
IAC

Abstract

MAAT is a mirror-slicer integral field unit that will be installed in OSIRIS in 2024, breathing new life into the GTC's work horse instrument. As well as the opportunity to perform spatially-resolved spectroscopy over a field of 10"x7", MAAT will also offer increased signal-to-noise and resolution for point sources with respect to the standard long slit mode.  As part of the preparations for the arrival of MAAT, we have implemented support for the reduction of OSIRIS data into the open-source, python-based spectroscopic reduction package PypeIt. Indeed, with the arrival of the new blue-sensitive CCD, PypeIt is now the only publicly available pipeline that continues to work for OSIRIS. With very little human intervention, PypeIt produces fully calibrated and coadded spectra that are near the Poisson limit for point sources. In this talk, I will present a brief overview of the philosophy behind PypeIt and demonstrate the ease with which OSIRIS data (and soon MAAT data) can be reduced.

 


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Thursday February 23, 2023
Prof. Mauro D'Onofrio
University of Padova

Abstract

I present a detailed analysis of the scaling relations of ETGs and suggest a way to predict the evolution of the distributions of galaxies in these planes. This new approach is able to account of several features observed in the FP projections and of the tilt of the Fundamental Plane.

 


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Friday February 17, 2023
Gabriel González Rial
IAC

Abstract

El próximo proyecto en estudiar es fondo cósmico de microondas (CMB) es LiteBIRD, un satélite de la JAXA que pretende estudiar la polarización de los modos-B. En él se encuentran integrados tres telescopios que recorren un rango frecuencial desde los 34 hasta los 448 GHz, donde se encuentran los Transition-Edge Sensor Detectors (TES), que operan a una temperatura de 100mK y que requieren de una estabilidad térmica estricta. En el Instituto de Astrofísica de Canarias se están estudiando mecanismos de control de la temperatura para convertir los requisitos térmicos en una realidad.


Youtube:

https://youtube.com/live/9Cq9Oy-aicY?feature=share


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Thursday February 16, 2023
Dr. Rogério Riffel
Astronomy Department of the Physics Institute of the Federal Universisty of Rio Grande do Sul (UFRGS)

Abstract

 

Since the pioneering studies linking the mass of supermassive black holes (SMBH) with the velocity dispersion of their host galaxies bulges it has become accepted that the products of active galactic nuclei (AGN) accretion and star-formation (SF) are somehow related. It is also accepted that nuclear SF and AGN can coexist in the inner region of galaxies, suggesting that the growth of SMBH (by gas accretion) and galaxies (by forming stars) are coupled.  In terms of galaxy evolution, it is established that AGN feedback plays a fundamental role by impacting SF (quenching, suppressing, or triggering). Cosmological simulations performed without the inclusion of feedback (SNR/AGN) effects are not able to reproduce the low and high luminosity ends of the galaxy luminosity function and underestimate the ages of the stars of the most massive galaxies when compared with observations.  While observations have shown that nuclear star formation is common in AGNs, properly measuring the stellar population properties in AGNs hosts is particularly difficult, since the active nucleus will dilute the absorption features and contribute to a large number of ionizing photons that will make it difficult to use emission line fluxes to infer the stellar properties.  In this seminar, I will discuss the results we have obtained in our group when mapping the stellar population in the inner region of active galaxies, with a special focus on the near-infrared spectral region, which allows for a better untangling of the AGN and stellar contributions for the spectral energy distribution of the galaxies. 
Zoom: https://rediris.zoom.us/j/81704623667?pwd=ejRHci8vTUR0QmZ5YkxrNTVoRU9mQT09

Meeting ID: 817 0462 3667
Passcode: 643393


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Tuesday February 14, 2023
Dr. Nicolas Martin
Observatoire Astronomique de Strasbourg

Abstract

Dwarf galaxies are powerful tools of near-field cosmology and galactic archaeology: their numbers, distribution, and star formation can be linked to both the tenets of LCDM (the missing satellite "problem," their (an)isotropic distribution, their dark matter content) and to the build up of their hosts and their environment (accretion, quenching). The exquisite detail offered by observation of the nearby Milky Way dwarf galaxies has built a picture of what dwarf galaxies are and how they evolved through time. In this talk, I will review the increasingly sharp view we are building of the dwarf-galaxy system of the Milky Way's "sister" galaxy, Andromeda, and emphasize key similarities and differences between these two systems of satellites in the hope to learn what features are common or, on the contrary, driven by the different pasts of the Milky Way and Andromeda.


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Tuesday February 7, 2023
Mattew Maniscalco
TNO

Abstract

TNO is big non-profit Dutch company with more than 3000 professionals. In this talk an introduction about TNO and its capabilities applied to astronomy will be presented. TNO has done the preliminary design of the Adaptive Secondary Mirror for the European Solar Telescope. TNO also develops other optical devices for ground based and space astronomy and also for optical communications.

 

Youtube: https://youtube.com/live/_b6Tdzr_Cq0?feature=share


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Tuesday January 31, 2023
Dr. Paolo Molaro
INAF-Osservatorio Astronomico di Trieste

Abstract

Lithium is a key   element which plays an important role in  astronomy  as well as everyday human life.  Nevertheless it is probably the only element whose astronomical origin is still a mystery.  A fraction of  about 30% of what is measured today was  made in the first 3 minutes of the Universe and about 10% is  made  by spallation  reactions of  cosmic rays with the atoms in the interstellar medium. However, as stars burn  Li in their hot interiors and what makes the remaining ~60%  is still unknown.  The recent detections of   7Li and 7Be in the outburst of   classical novae is a landmark in the solution of this long standing mystery. The discovery   confirms a theoretical speculation  made about 50 years ago    but  which was never  supported by observations.   Since then  the  presence of Be-7 has been confirmed to be ubiquitous in about a dozen classical novae and very recently also in the  recurrent nova RS Oph that blew out in August 2021.  However, the observed values show  tension with theory  being one order of magnitude greater than predictions.  Detailed Li Galactic chemical evolution models   assuming the "observed" yields  show that indeed  Novae could  be the long sought  source for the Galactic  7Li. 


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Friday January 27, 2023
Prof. Belén Gavela
IFT/UAM

Abstract

 

 After introducing the concepts of axions and axion-like-particles (ALPs) and their signals, true axions which can be either much heavier or much
lighter than the canonical axion will be discussed. The implications for dark matter, neutron stars and gravitational waves searches will  also be addressed.