Últimas charlas

The remarkable success of recent cosmology in pinpointing a consistent concordance model relies on several foundational assumptions, including homogeneity, isotropy of the universe, and scale invariance, among others.  Increasingly precise cosmological observations, such as the exquisite measurements of the CMB sky from the ESA Planck space mission, have opened up the possibility of robust, independent tests of these assumptions. I will present key results from my research programs on this theme and review the current status of the research.

During the last few decades, we've begun to glimpse the universe not just with photons, but also with other messengers like cosmic rays, neutrinos, and even gravitational waves. I will show why photons, cosmic rays, and neutrinos are fundamentally interconnected—as dark matter may also be—and why very-high-energy gamma rays are a key domain in multi-messenger astronomy. I'll emphasize the role of a few key experiments in the Canary Islands in this field, and discuss some of the latest results that are opening new scientific prospects for the upcoming generation of detectors.

I will give a brief introduction to the RH code, illustrated with some examples. The code is a general purpose radiative transfer code capable of solving the coupled equations of  radiative transfer and statistical equilibrium under general Non-LTE conditions in four different geometries, 1-, 2-, and 3D plane geometry, and spherical geometry. In addition the code can treat polarization under the Zeeman regime and partial frequency redistribution (PRD) in strong lines. In addition the code can be used to solve radiative transfer, optionally with polarization, in molecules. User tools with a graphical interface in IDL or Python routines to read the output , with example Jupyter notebooks are also available. If time permits I will run a few hands on examples.

En el Centro de Sistemas Ópticos Avanzados, CSOA, es posible diseñar y fabricar elementos ópticos de gran tamaño. Dentro de este laboratorio se ha construido una instalación de recubrimientos óptico destinada a diseñar y crear recubrimientos para filtros, espejos y similares, con tamaños que van desde unos pocos centímetros hasta aproximadamente 1,5 m.

Actualmente se ha comenzado a experimentar con materiales para filtros, recubrimientos antireflejantes, espejos de aluminio y plata protegida y otros materiales para recubrimientos metálicos. Nuestras capacidades actuales incluyen una máquina de recubrimiento por sputtering, para recubrimientos de hasta 1.5 m de diámetro, instalada en IACTEC y dos máquinas para recubrir ópticas de medio metro, que se encuentran en el IAC

The intrinsic magnetic fields of exoplanets influence the structure of their atmospheres and plasmaspheres and, consequently, the observational manifestations of transit absorptions. In this talk, we present a novel method designed to constrain the presence or absence of relatively weak MFs. We will show how the quantum effect of atomic alignment, which alters the absorption probabilities of individual transitions within multiplets from their equilibrium 2J + 1 values, provides a sensitive probe for fields as weak as 0.001 G. We applied this method to some available observations of exoplanet transits and demonstrated that we indeed have the ability to estimate the intrinsic magnetic field of some exoplanets right now

X-ray binaries (XRBs) are binary systems where a compact object, either a black hole or a neutron star, accretes matter from a stellar companion via an accretion disc. As this material spirals in, it heats up and emits X-rays, typically exhibiting transient outburst behaviour.

During these outbursts, XRBs often transition between hard states (dominated by inverse Comptonization in a hot-electron corona) and soft states (where thermal emission from the disc prevails). In the hard states, XRBs display strong variability across multiple timescales, frequently featuring quasi-periodic oscillations (QPOs).

To probe these fast dynamics, we employ spectral-timing Fourier techniques, which allow us to infer the geometry of the accretion flow and the mechanisms governing radiation propagation in the vicinity of the compact object, crucial information not directly accessible through the stationary spectrum alone.

In this talk, I will delve into the spectral-timing phenomenology of XRBs and present the insights gained from applying a time-dependent Comptonization model, aiming to deepen our understanding of the state transition and outburst evolution in these complex systems.

EL IAClink establecerá instalaciones de vanguardia en los Observatorios del Roque de los Muchachos (La Palma) y del Teide (Tenerife) para avanzar significativamente en la investigación y el desarrollo de las comunicaciones ópticas clásicas y cuánticas. Aprovechando la configuración atmosférica horizontal de 144 km única en el  mundo —comparable al trayecto visual de los satélites en órbita baja cuando están en el horizonte—, las instalaciones proporcionarán un entorno excepcional para probar la viabilidad y eficacia de los enlaces ópticos bajo condiciones de turbulencia significativa. Este sitio, con su alta disponibilidad de condiciones atmosféricas óptimas, tanto de día como de noche, es ideal para simulaciones realistas y experimentación avanzada, maximizando las posibilidades de éxito en pruebas críticas de comunicación. El uso histórico de este enlace, incluidas contribuciones a investigaciones galardonadas con el Premio Nobel, como las del físico Anton Zeilinger en 2022, subraya su valor único para la comunidad científica global. Al aprovechar estas capacidades, la infraestructura no solo fomentará avances tecnológicos, sino que también consolidará la posición de España como líder en investigación de comunicaciones ópticas y cuánticas a nivel internacional.

In the last years, ground-based and space observations are bringing a wealth of constraints on the chemical composition of exoplanet atmospheres. Chemical models are particularly useful because they provide the theoretical framework to interpret these observations and make new predictions. I will describe how such models are built and discuss some recent efforts aimed to provide a more accurate description of the atmospheric composition, with emphasis on the mutual influence of temperature and disequilibrium composition, the quantification of abundance uncertainties, and the variation of the composition as a function of longitude.