Recent Talks

 ¿Cómo podemos saber si el instrumento que hemos diseñado es suficientemente seguro?

¿Quién debe realizar ese análisis?

¿Estamos dedicando suficientes recursos a la seguridad de las máquinas?

Durante la charla, intentaremos abordar estas y otras cuestiones sobre seguridad. Prometo no basar la charla en el repaso de normativa y leyes para no torturar demasiado (y por miedo a represalias), pero sí repasaremos el flujo de diseño que se debe seguir en los proyectos para obtener un sistema de seguridad adecuado al instrumento o máquina.

Unirse a la reunión Zoom

https://rediris.zoom.us/j/82384394724

In the local universe most of the stellar mass is in passive galaxies, where star formation is
absent or at very low levels. Understanding what are the mechanisms that have been
responsible for quenching star formation in galaxies, and transforming them into passive,
quiescent systems, is one of the main observational and theoretical challenges of extragalactic
astrophysics. I will give a brief overview of the several possible quenching causes and physical
processes that have been proposed so far, ranging from feedback from black hole accretion and
starburst activity, to effects associated with the large scale environment in which galaxies live.
Although most of these mechanisms and causes play a role in different classes of galaxies and
at different epochs, multi-band observations are providing growing evidences that just a few of
them play the key, dominant role.
I will conclude by providing prospects for further investigating these aspects and tackling open
questions with the next generation of observing facilities.

Mark I is a part of the origin of the IAC, operating in the El Teide Observatory since 1975, in three different locations until reaching the Solar Pyramid "van der Raay" in 1987. Every day, weather permitting, it has been providing precise measurements of the radial velocity of our star. It began to perform continuous daily observations from July 1984 and, until December 2020, 10169 out of 13408 possible days (76%) useful data has been gathered. Designed, updated, maintained and operated by the Helioseismology team at the IAC and the University of Birmingham (UK), more than 100 people, from TOTs and weekend fellows to professors, have contributed to this endeavour. It was a true pioneer, key in the birth and development of Helioseismology and Astroseismology as branches of modern Astronomy.

Mark I is a resonant scattering spectrophotometer that measures the radial velocity of integral sunlight using the KI-769.9 nm spectral line. It has been a pioneer and reference for calibration of other instruments: MarkII, IRIS, Cannon, Stellar, Space, BiSON, GOLF, which have also worked in different ground-based observatories and in space missions such as SoHO (1995-).

Its precision, in a single measurement of the solar radial velocity, is less than 1 m/s, and the one achieved so far is less than 1 cm/s at frequencies around 0.1 mHz (gravity modes zone) and less than 1 mm/s at 3 mHz (acoustic modes zone). It measured for the first time the spectrum of solar acoustic modes (from 1.8 to 4.2 mHz) of small degree (ℓ <= 3): their frequencies, amplitudes and lifetimes, their rotational splitting; also its variations with the cycle of solar activity. He has explored gravity modes, measured the spectrum's background, and determined the acoustic cut-off frequency in the solar photosphere. All this has led to numerous discoveries that have been published in around 40 doctoral theses at different universities and more than 600 papers in international journals and books. These works have been already cited around 10,000 times in scientific literature.

In this talk I will briefly review its history throughout more than 45 years, an entire academic life, and I will raise some suggestions on its scientific use from now on.

Saliéndome un poco de la tónica habitual de los seminarios de Instrumentación, donde los ponentes muestran un aspecto determinado del trabajo que están realizando en su proyecto, yo he preferido retomar una presentación que hice en 2015 con motivo del Día de Nuestra Instrumentación y actualizarla y ampliarla. Bajo el título de "Catástrofes y accidentes astronómicos", en esta presentación mostraré lo peligroso que pueden ser los incendios, huracanes y terremotos en los telescopios, junto con los efectos de algunos accidentes y fallos humanos. He centrado la presentación en los casos más llamativos y, sobre todo, en aquellos donde he encontrado disponible material gráfico.

La realización del Proyecto de identificación, clasificación, valoración y propuestas de medidas para la conservación de litografías y otras obras del Instituto de Astrofísica de Canarias (A20100211/20100165-FGULL) ha mostrado las diversas tipologías que conforman el patrimonio de dicha institución. Durante esta charla daremos a conocer este patrimonio centrándonos en la obra seriada de artistas nacionales e internacionales de reconocido prestigio, que utilizan técnicas de grabado calcográfico y técnicas de estampación planas en su universo gráfico. 

The formation and evolution of galaxies across cosmic time proceeds in different phases, paced by their internal evolution and external factors like gas accretion and mergers. The complex and always changing interplay between these mechanisms drives the assembly of galaxies and the physical conditions for star formation, which leaves observable imprints on the stellar populations. Large astrometric and spectroscopic surveys (e.g. Gaia, APOGEE, GALAH) collect the signatures of these past events in the building history of the Milky Way. However, simulations and models are necessary to decode the data. In this talk, I will present results from a series of hydrodynamical simulations of Milky Way-like galaxies, both in isolation and in cosmological context using the VINTERGATAN simulation. I will show the crucial role of mergers, and of the end of the merger phase, in forming the thick and thin Galactic discs, and making the transition between the two. I will then nuance this conclusion by explaining why the secular consumption of gas enables a similar transition, as well as the emergence of spirals, without any external factors.

The new generation of spectrometers designed for extreme precision radial velocities enable correspondingly precise stellar spectroscopy. It is now fruitful to theoretically explore what the information content would be if stellar spectra could be studied with spectral resolutions of a million or more, and to deduce what signatures remain at lower resolutions. Hydrodynamic models of stellar photospheres predict how line profiles shapes, asymmetries, and convective wavelength shifts vary from disk center to limb. Corresponding high-resolution spectroscopy across spatially resolved stellar disks is now practical using differential observations during exoplanet transits, thus enabling the testing of such models. A most demanding task is to understand and to model spectral microvariability toward the radial-velocity detection of also low-mass planets in Earth-like orbits around solar-type stars. Observations of the Sun-as-a-star with extreme precision spectrometers now permit searches for spectral-line modulations on the level of a part in a thousand or less, feasible to test against hydrodynamic models of various solar features.

Planetary systems have been found systematically orbiting main sequence stars and red giants. But the detection of planets per se during the white dwarf phase has been more elusive with only 3 systems.  We have, however, ample indirect evidence  of the existence of planetary debris around these systems in the form of material acreted onto the white dwarf, disks and even planetesimals. In this talk, I will review how we can put the pieces together: how we can reconcile what we see in white dwarfs with what we can infer regarding the evolution of planetary systems from the main sequence phase.

Sunrise III es un observatorio solar diseñado para realizar observaciones epesctropolarimétricas a bordo de un globo estratosférico. Este observatorio cuenta con un telescopio de un metro de apertura que da luz a tres instrumentos posfocales principales: SUSI (Sunrise Ultraviolet Spectropolarimeter and Imager), SCIP (Sunrise Chromospheric Infrared spectra-Polarimeter) y TuMag (Tunable Magnetograph).

What is academic freedom? Why do we need it? What specific rights do we have as teachers and researchers? These questions are addressed in relation to the UNESCO 1997 recommendation for higher-education teaching personnel. It is observed that having good rules and regulations is one thing, what happens in practice often quite another. The final part of the talk lists the main current threats to academic freedom in the Western world and what can be done to counter them by efficient means, with a case study from Sweden.

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[English version below]

Extracto del Acta del Comité Director del IAC del 24 de noviembre de 2021:

“En relación con el seminario impartido recientemente en el IAC por el Prof. Erik J. Olsson (Univ. de Lund), la Dirección del centro lamenta profundamente que en el transcurso del mismo se realizaran afirmaciones absolutamente contrarias con nuestro firme compromiso con la igualdad de género y con los principios de nuestro Código Ético.

 Este profesor no se encontraba en visita de trabajo en nuestro centro. Su ponencia fue propuesta, de manera puntual, por un investigador del IAC a la Comisión de Seminarios, quien revisó el título y el resumen facilitados de la ponencia. Esta Comisión, por la información proporcionada, no podía deducir los contenidos totalmente inapropiados que finalmente fueron expuestos en varias transparencias y manifestados verbalmente por el referido ponente.

 La Dirección del centro expresa su rotunda desaprobación ante lo ocurrido y mantiene la medida de cancelar la distribución y el acceso a la ponencia a través de los medios de comunicación propios del centro; confirmando  la acción tomada, como medida preventiva por el Director, en el momento en el que se tuvo noticia de lo ocurrido.

 Se recuerda la responsabilidad que tiene todo el personal del centro con el cumplimiento de nuestro Código Ético, y los principios y fines del IAC en el desarrollo de nuestra actividad. Este compromiso es extensivo al personal externo que sea invitado para la realización de actividades en nuestro instituto.”

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[Text extracted from the acts of the Direction Committee meeting held on November 24th 2021]

"In relation with the seminar recently given by Prof. Erik J. Olsson (Univ. of Lund, Sweden), the IAC Direction deeply regrets statements made during that seminar since those statements fully oppose our firm committment towards gender equality and the principles of our ethical code.   

Prof. Olsson was not in an offical visit at IAC. His seminar had been proposed to the IAC's Seminar Commission by an individual senior researcher at IAC. This Commission revised the title and the abstract provided for this talk, from which it could not foresee the totally inappropriate content exposed in several slides, and verbally manifested by the speaker.

The direction of IAC expresses its absolute dissaproval of these events, and maintains its measure of blocking all institutional channels for the access and/or distribution of the recording of this seminar. Hereby we confirm that measure, which was adopted preliminarily by the IAC's direction when it was first informed of these events.

We remind all IAC staff of our responsibility towards the observation of our Ethical Code, together with the IAC's principles and objectives in the development of all our activities. This committment is extended to any external personnel that is present at our institution.”

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