Recent Talks

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


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Tuesday June 22, 2021
Dr. Christophe Morisset
Universidad Autónoma Nacional de México

Abstract

Artificial intelligence techniques are increasingly used in our daily lives. They also play an important role in science, including astrophysics. I am particularly interested in the use of machine learning regressors. I will present an overview of the current situation and some recent uses of these methods in the study of planetary nebulae or HII regions.



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Friday June 18, 2021
Dr. Haresh M. Chulani
Departamento de Electrónica, Instituto de Astrofísica de Canarias

Abstract

Atrás quedaron aquellos tiempos en que el IAC fue pionero en alta resolución espacial aplicada a la observación del Sol, gracias al desarrollo de un estabilizador bidimensional de imagen solar en tiempo real. Hoy, veinticinco años después, el Área de Instrumentación desarrolla un banco de pruebas de óptica adaptativa diurna para ponerse al día, y optar a encargarse de la óptica adaptativa multiconjugada (MCAO) del Telescopio Solar Europeo (EST). En esta charla hablaré de los retos de la MCAO diurna desde el punto de vista de control, y presentaré el banco de pruebas y las estrategias de control que se pretenden probar.

https://youtu.be/2GHr6Ow5g0I


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Thursday June 17, 2021
José Eduardo Méndez Delgado
IAC

Abstract

We present some results on a project based on high-resolution UVES@VLT spectroscopy and HST imaging of photoionized Herbig-Haro (HH) objects in the Orion Nebula. We study physical conditions, chemical abundances and other properties such as proper motions and the origin of the driving jets. Our study will include at least 9 HH objets, of which we will focus on HH529II, HH529III and HH204 in this talk. Our data allow us to separate the spectrum of the outflows from the main nebular emission, studying each object with an unprecedented detail. The HHs are located at different distances from the main ionization source of the Orion Nebula, with different ionization/physical conditions and flow velocities. In all objects, the electronic density (ne) is substantially higher than in the surrounding Orion Nebula, while the electronic temperature (Te) is maintained under photoionization equilibrium for the most abundant ion stages. In HH204 we observe a Te([OIII]) gradient due to the contribution of [OIII] emission from the cooling layer behind the bow shock, which is also detected in the HST imaging. The ionization degree of the gas in the different HH objects is very different, allowing us to determine the chemical composition of the Orion Nebula under both ionization conditions, avoiding the use of ionization correction factors (ICFs) for many elements. HH204 shows an abundance discrepancy  -the difference between abundances derived from recombination and collisionally excited lines- thas is actually zero. We find direct evidence of dust destruction in the bow shock in all objects. This increases the gaseous abundances of Fe, Ni and Cr with respect to the Orion Nebula ones. We show that a failure to resolve the different kinematic components -as in a low spectral resolution spectrum- can lead to significant error in the determination of chemical abundances -40% underestimate of O in the case of HH204-, mainly due to incorrect estimation of the electron density.


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Tuesday June 8, 2021
Dr. Hector Socas-Navarro
IAC

Abstract

In this talk I'll present results from a recent paper in which we have developed a new analysis technique for solar spectra based on artificial neural networks. Our first test applications yielded some unexpected and interesting results. The fine-scale network of temperature enhancements in the quiet middle and upper photosphere have a reversed pattern. Hot pixels in the middle photosphere, possibly associated with small-scale magnetic elements, appear cool at higher levels (log(tau)=-3 and -4), and vice versa. We also find hot arcs on the limb side of magnetic pores, which we interpret as the first direct observational evidence of the "hot wall" effect. Hot walls are a prediction of theoretical models from the 1970s which had not been observed until now.

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Friday June 4, 2021
Manuel Amate Plasencia
IAC

Abstract

En los ultimos años hemos visto el desarrollo de instrumentación para la búsqueda de exoplanetas por el método de la Velocidad Radial.

La tendencia es que cada generación de espectrógrafos ultra-estables sea un orden de magnitud mejor que la anterior. Pero ¿qué tienen en común estos intrumentos?, ¿Qué los distingue del resto?

El IAC participa en instrumentos de tres generacines: HARPS3, ESPRESSO y HIRES; en esta charla, aprovechando la experiencia adquirida, se hablará de las estrategias que han permitido a estos instrumentos tener alta resolución, alta estabilidad y alta repetibilidad.


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Thursday June 3, 2021
Dr. Javier Redondo
Universidad de Zaragoza

Abstract

We introduce the strong CP problem and the existence of the Axion as a possible solution. 

We discuss the possibility that axions are the dark matter of the Universe and the possible ways to

detect it or disprove it using: direct laboratory experiments as well as astrophysical and cosmological

arguments. 

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Thursday May 27, 2021
Dr. Manuela Bischetti
INAF/Trieste

Abstract

This talk will be dedicated to luminous (LBol~1E47 erg/s),
high-redshift quasars, which are ideal targets to investigate (i) feedback
from SMBHs, and (ii) the early growth phases of giant galaxies. I will
present evidence of  SMBH-driven outflows  at all Cosmic epochs, back to
the early Universe. These outflows involve all gas phases (molecular,
neutral, ionised) and extend on nuclear to galactic and circum-galactic
scales. I will report on the first systematic study of the molecular gas
properties in the host-galaxies of the most luminous quasars, fundamental
to probe the impact of SMBH feedback on the host-galaxy evolution. I will
show that luminous quasars pinpoint high-density sites where giant galaxies
assemble, and I will discuss the major contribution of mergers to the final
galaxy mass. To this aim, I will present a wealth of multi-wavelength (UV
to sub-millimeter) observations from the WISE/SDSS hyper-luminous quasars
survey  at z~2-5 (WISSH), and recent results from the ESO large program
XQR-30, the Ultimate X-SHOOTER Legacy Survey of Quasars at the Reionization
epoch.

 


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Tuesday May 25, 2021
Drs. Olga Mena
IFIC

Abstract

In this talk, we shall review the impact of the neutrino properties on the different cosmological observables. We shall also present the latest cosmological constraints on the neutrino masses and on the effective number of relativistic species. Special attention would be devoted to the role of neutrinos in solving the present cosmological tensions.


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Friday May 21, 2021
Ángeles Pérez de Taoro
IAC

Abstract

LA GESTIÓN DE PROYECTOS de instrumentación EN EL IAC.
La Idea de esta charlas es exponer los problemas más cotidianos, y quizá desconocidos por los no gestores, en la gestión de proyectos de instrumentación, y si es posible plantear y debatir posibles mejoras.

 

Unirse a la reunión Zoom
https://rediris.zoom.us/j/83152380549?pwd=Z2hzdnBwbVJQaWlISzRmRVV4akpHQT09

ID de reunión: 831 5238 0549
Código de acceso: 204966


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Thursday May 20, 2021
Dr. Guillaume Thomas
IAC

Abstract

At present, our understanding of the formation history of the MW is limited due to the complexity of observing the imprints of accretion events and of reproducing them in numerical simulations. Moreover, though being the only galaxy, in which the Galactic potential can be probed in detail, the distribution of mass in the MW, and hence of the dark matter, is poorly constraint, especially at large distances. In addition, the MW is not isolated, and it has recently been suggested that the infall of the LMC can induce a perturbation in the stellar and dark matter distribution of the MW. As a consequence, the details of the formation history of our Galaxy are still unknown, such as the number of accretion events, the mass of the accreted galaxies, and the epoch of these events. Yet this information is crucial to understand our environment and to constrain the theoretical models and simulations that try to reproduce it.

One of the major challenges of the field is that a tremendous number of multi-aspect (astrometric, photometric and spectroscopic) observations at significant depth is required to study the morphology, the kinematics and the chemistry of the outskirts of our Galaxy, where are located the signatures of these events. Hopefully, the advent of recent and incoming complementary large surveys, such as the European Gaia mission, UNIONS (Ultraviolet Near Infrared Optical Northern Survey), Pristine, Pan-STARRS (PS), WEAVE or LSST (Legacy Survey of Space and Time), is offering a new global point of view on our Galaxy’s halo, allowing us to precisely probe the Galactic potential our the MW, and to retrace itsaccretion history.

In this talk I will present recent works that have been conducted to better catarerized our Galaxy and its history with some of the existing surveys mentioned above. In addition, I will present the major improvement that will bring this new generation of large, multi-aspect surveys, to study both our Galactic history, as well as the fundamental nature of the dark matter.



Upcoming talks


More upcoming talks

Recent Colloquia


Recent Talks