Recent Talks

The MAGIC telescopes are a stereoscopic system
of two 17m mirror diameter Cherenkov telescopes for gamma-ray observations, in operation since many years on the island of
La Palma at the Observatorio del Roque de los Muchachos.
A new installation allows us to use those telescopes as optical
intensity interferometer which enables us to measure the size of bright
objects in the range of 0.6-1.5 milli-arcsec and other physical
parameters. In this presentation the setup is explained, our physics
targets, first results and also a future outlook of this project
with respect to the Cherenkov telescope array (CTA) currently
in construction.

Dentro de la Astrofísica las curvas de luz conforman una herramienta fundamental en el estudio de cuerpos celestes de brillo variable, resultando útiles para detectar tránsitos de exoplanetas, evaluar el carácter variable de determinadas estrellas, etc. Con el fin de analizar en tiempo real las curvas de luz que se pretendan obtener con el telescopio IAC80, se ha desarrollado una pipeline en Python basada en fotometría diferencial, haciendo uso del módulo Photutils.  Así, en esta charla se pretende explicar en primer lugar el funcionamiento del programa, mostrar algunos resultados obtenidos, y por último ilustrar cómo hacer uso de la pipeline.

Tema: Seminario de Instrumentación: lc80, la nueva pipeline en tiempo real para análisis de curvas de luz del telescopio IAC80

Hora: 9 jul. 2021 12:00 p. m. Atlantic/Canary

Unirse a la reunión Zoom

https://rediris.zoom.us/j/88394669340

https://youtu.be/VrppDSMYq2g

We summarize here some of the results reviewed recently by Sanchez (2020) and Sanchez  et al. (2021), comprising the advances in the comprehension of galaxies in the nearby universe based on integral field spectroscopic galaxy surveys. We review our current knowledge of the spatially resolved spectroscopic properties of low-redshift star-forming galaxies (and their retired counterparts) using results from the most recent optical integral field spectroscopy galaxy surveys. We briefly summarize the global spectroscopic properties of these galaxies, discussing the main ionization processes, and the global relations described by the star-formation rates, gas-phase oxygen abundances, and average properties of their stellar populations (age and metallicity) in comparison with the stellar mass. Then, we present the local distribution of the ionizing pro-cesses down to kiloparsec scales, and how the global scaling relations found using integrated parameters (like the star-formation main sequence, mass–metallicity relation, and Schmidt–Kennicutt law) have local/resolved counterparts, with the global ones being, for the most part, just integrated/average versions of the local ones.  The main conclusions of the most recent explorations are that the evolution of galaxies is mostly governed by local processes but clearly affected by global ones.

Massive stars are generally fast rotators, however, with significant dispersion. We discuss the hypothesis that all OB stars are all born with very similar spins, with slower and faster rotators being produced by close binary evolution. We review supporting evidence from recent observations of young and rich star clusters, from OB star surveys, and from dense grids of detailed binary evolution models. We connect the OB star spins with the likelihood of evolved/compact binary companions, and with the variety of the explosive end states of massive stars.

Youtube: https://youtu.be/yJHMQFmLsGE

En esta charla se pretende realizar un resumen del análisis de stray light que se está realizando en el instrumento Harmoni, tanto a nivel de sistema como de subsistema, analizando las ventajas e inconvenientes de la estrategia utilizada.

Tema: Seminario de Instrumentación: Análisis de stray light en instrumentación astrofísica

Hora: 2 jul. 2021 12:00 p. m. Atlantic/Canary

https://youtu.be/GRrUM_A1sGs

This talk will present an overview of what Latex is, discuss when to  use it and when not, show installing and editing options, introduce classes and packages, and give some usage recommendations and troubleshooting tips.

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.

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

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.