Recent Talks

Durante el presente seminario hablaremos sobre el estado actual del banco óptico GTCAO. Se hará énfasis en las tareas mecánicas en curso referentes a las instalaciones auxiliares para la integración y comisionado del banco, planteando problemáticas generales de las tareas y soluciones adoptadas.

Enlace Youtube: https://youtu.be/4WTGKMGwd7o

In the last decade, Python went from being a moderated-used programming language in the astronomical community to the de-facto standard in Astronomy. Its recent growth has been spectacular, thanks to the coordination and work of the community to create astropy, the core astronomy library, as well as other base libraries like numpy and matplotlib. However, the current scientific/astronomical ecosystem for Python is huge and sparse, introducing many types of objects and methods, often confusing at the beginning.

In this SMACK talk I will describe the current status of the Python ecosystem for astronomy and introduce the most import elements of the core libraries, numpy and astropy, showing with practical examples how they provide new impressive capabilities to deal with data, catalogs, coordinates and much more, making life easier for astrophysicists.

The detections of gravitational waves are opening a new window to the Universe. The nature of black holes and neutron stars may now be unveiled, but gravitational radiation may also lead to exciting discoveries of new exotic compact objects, oblivious to electromagnetic waves. In particular, Advanced LIGO-Virgo recently reported a short gravitational-wave signal (GW190521) interpreted as a quasi-circular merger of black holes, one at least populating the pair-instability supernova gap. We found that GW190521 is also consistent with numerically simulated signals from head-on collisions of two (equal mass and spin) horizonless vector boson stars (aka Proca stars). This provides the first demonstration of close degeneracy between these two theoretical models, for a real gravitational-wave event. 

A la hora de planificar un proyecto la gestión de las dependencias técnicas entre tareas ya supone un desafío.  Añadamos a la coctelera las dependencias circunstanciales y, por qué no, sumerjamos el experimento en una organización matricial donde todos los miembros del equipo trabajan en varios proyectos.

"Classical Wolf-Rayet (WR) stars" represent a class of hot, hydrogen-depleted stars wtih powerful stellar winds and are prominent progenitors of black holes. Next to their unparalleled radiative and mechanical energy feedback, they offer unique probes of massive-star evolution at the upper-mass end. To become a classical WR star, single stars require substantial mass-loss to strip their outer, hydrogen-rich layers, implying that only very massive stars could enter the WR phase. However, mass-transfer in binaries can further aid in the stripping of stars and form Wolf-Rayet stars, or more generally helium stars, at lower masses.  Due to the decrease of mass-loss with metallicity, it has been predicted that WR stars at low metallicity tend to form in binaries. However, this has so far not been supported by observations.

In my talk, I will give an overview on our current knowledge of the properties of Wolf-Rayet populations in the Galaxy and the Magellanic Clouds based on exhaustive spectral analyses. I will illustrate why binary formation does not necessarily dominate the evolution of WR stars at low metallicity, and highlight important discrepancies between theory and observations of WR stars. I will discuss the observed rarity of intermediate mass helium stars, and present recent reports of unique helium stars in the exotic binaries LB-1 and HR 6819.

Recent progress in observations of Rossby-type waves on the Sun revived the interests towards the waves. Though the hydrodynamic Rossby waves are well studied in the Earth context, ubiquitous existence of magnetic field in the atmosphere/interior of the Sun requires to study the waves in magnetohydrodynamics. The talk will cover the recent direct observations of Rossby waves on the Sun, theoretical development of magneto-Rossby wave theory and the possible connection of the waves to observed long and short term variations in solar magnetic activity.

El instrumento WEAVE está siendo integrado en el WHT, el IAC ha entregado los paquetes de trabajo que son de su responsabilidad a falta de realizar el commissioning final. En esta charla se hará un repaso al sistema de control del instrumento con los puntos claves, aciertos e impresiones que podrían ser beneficiosos para otros proyectos de instrumentación como puede ser HARMONI.

Unirse a la reunión Zoom
https://rediris.zoom.us/j/86905885211?pwd=Sys2RVNpRzE0REFFRGtuRjdKak9tUT09

ID de reunión: 869 0588 5211
Código de acceso: 563187

The search for extrasolar planets is one of the fastest-growing fields of astronomy. This rapid growth was both made possible by the development of instrumentation and motivated it, creating a virtuous cycle that impacted positively several fields of research.

In this talk I will present the latest planet-hunting spectrograph ESPRESSO, installed at ESO's VLT. Targeting a radial velocity precision of 10 cm/s, ESPRESSO has the declared goal of detecting an Earth-mass planet inside the habitable zone of a main-sequence dwarf star. I will discuss the first results, ongoing campaigns, and reveal a bit of what the future holds for us.

La gestión de documentos es una tarea compleja que implica múltiples cuestiones, especialmente en proyectos como la definición y creación de un telescopio.  Una correcta gestión documental requiere entre otras cuestiones:

• Ser fuente única de verdad: Los documentos deben gestionarse desde un punto central que actúe como fuente única de verdad permitiendo la localización y actualización de los mismos.
• Permitir búsquedas ágiles, simples y eficaces: Aunque el volumen de documentos sea elevado las búsquedas deben mantenerse ágiles y sencillas permitiendo localizar los documento en base a sus características o a la información que contienen.
• Facilitar la coherencia de formato: Los documentos creados en un proyecto deben mantener un formato y esquema coherente mediante la utilización de plantillas.
• Agilizar la creación de documentos: La solución debe permitir la creación de nuevos documentos de forma sencilla realizando de forma automatizada tantas tareas como sea posible (codificación, pre-formateo del documento,...).
• Gestión bibliográfica: los documentos requieren de un mecanismo de codificación que permita la identificación de los mismos.
• Permitir versionado de documentos: Los documentos evolucionan a lo largo de su ciclo de vida dando lugar a versiones que deben ser almacenadas e identificadas.

Las plataformas de gestión documental existentes "out of the box" no cubren el 100%  de estos requisitos. Sin embargo, ofrecen mecanismos de extensión que permiten ampliar sus capacidades. Desde la oficina de proyecto del EST hemos desarrollado una herramienta para la gestión de los documentos del proyecto,  a partir de soluciones libres como Alfresco o Carbone.io, que cubre todas estas necesidades.

The majority of massive stars are born in close binary systems with orbital periods of a few days. At some point during their core-hydrogen burning phase, both members of these close binaries inevitably overflow their Roche lobes simultaneously and get bound by a common equipotential surface. The characteristics of this `contact phase’ will determine the fate of the binary system: whether the stars will merge on the main sequence or evolve further towards becoming potential gravitational-wave progenitors. Although data is available for several of these massive contact binaries in the Magellanic Clouds and the Milky Way, there has not been a dedicated study of these systems so far. In this talk, I will present the first set of detailed binary models covering a wide range of initial masses (20-80 Msun) and initial periods (0.6-2 days), focusing especially on the properties of the contact phase. We find that our models can approximately reproduce the period-mass ratio trend of the observed binaries although for the higher masses of our grid, our model predictions do not match with what is observed. We also find that those binary models which are in contact over nuclear timescales evolve towards equal masses before ultimately merging on the main sequence. This first study of massive contact binaries has allowed us to gain insights into the physics of massive contact systems and also provide reasonable predictions for the final fate of close massive binary stars.