Recent Talks

The era of gravitational wave astronomy has dawned, allowing us not only to observe the universe but also to "listen" to it through gravitational waves. When a compact object ventures too close to a supermassive black hole, it becomes captured due to the emission of gravitational waves, eventually being swallowed whole as it crosses the event horizon. During this process, the system radiates energy, which can be viewed as a snapshot containing detailed information about the geometry of spacetime and the physical parameters of the system with extraordinary precision. Intriguingly, this information may also hold clues about the topology of spacetime, suggesting a potential link between geometry and topology in the strong-field regime of gravity. This phenomenon effectively maps the warped spacetime, serving as a unique probe of gravity in its most extreme regime. Thanks to these captures, we can now tackle fundamental questions: Do black holes truly exist? How do they accumulate their colossal mass over cosmic history? And what is the true nature of their event horizons? 

The first detection of an exoplanetary atmosphere dates back merely two decades and has undergone a veritable boom with a wide range of dedicated instrumentation. I will give a short overview of how we learn more about the composition of exoplanets and in consequence about the planet population and our place in it.  I will put a special emphasis on high-resolution spectroscopy and how we employ it now to observe the atmospheric dynamics in far-away worlds, such as churning jet-streams and powerful sub-to-antistellar flows. Looking to the future and the paradigm shift of the ELT-era, I will explore the implications of these technical advancements, with a particular focus on how we can leverage high-resolution spectroscopic data to decipher the complex interplay between dynamics and composition in these distant worlds in synergy with existing and upcoming space missions.

"DESI DR2 results: a hint for dynamical dark energy?" - José Ramón Bermejo Climent

“Euclid Q1 data release” - Marc Huertas Company

It is widely accepted that most galaxies undergo an active phase during their evolution. The impact of the energy released by active galactic nuclei (AGN) has been proposed as a key mechanism responsible for regulating star formation (SF) by influencing the interstellar medium (ISM) of the host galaxy. Dust, gas, and molecular components are key tracers of the interplay between the supermassive black hole (SMBH) and its host. The infrared (IR) regime hosts numerous spectral features, such as fine-structure lines, dust and ice features, organic molecules, hydrogen, and water, that act as sensitive barometers of the physical conditions in the ISM. These features are essential for tracing AGN feedback from the innermost regions (tens of pc) out to kiloparsec scales. With its unprecedented sensitivity and resolution, the James Webb Space Telescope (JWST) now enables detailed measurements of the gas flow cycle in AGN. Nearby AGN provide the additional advantages of high spatial resolution and strong signal-to-noise, allowing us to disentangle the key coupling mechanisms in their different phases. In this talk, we will present recent findings and ongoing work from the Galaxy Activity, Torus, and Outflow Survey (GATOS), with a focus on results from JWST and complementary observations such as ALMA and GTC.

Fast X-ray Transients (FXTs) are minute-to-hours long flashes of X-rays, first discovered serendipitously in X-ray satellite data (mainly Chandra and XMM-Newton). They are proven to be caused by energetic extra-galactic phenomena. Currently, Einstein Probe is revolutionizing the field by discovering many FXTs and, crucially, by their low-latency announcement thereof. These extra-galactic FXTs are ubiquitous: their density rate is several hundred per year per Mpc^3. FXTs have been proposed to arise from double neutron star mergers, tidal disruption events involving an intermediate-mass black hole and a white dwarf, and from off-axis or sub-luminous gamma-ray bursts. Brief extra-galactic FXTs also arise in supernova shock breakouts. Contemporaneous multi-wavelength detections possible only in the current Einstein Probe era show that FXTs originate from more than 1 progenitor. I will discuss the most recent findings and provide some (potential) science questions to be answered using FXT observations.

The laser increased the intensity of light that can be generated by orders of magnitude and thus brought about nonlinear optical interactions with matter. Chirped pulse amplification, also known as CPA, changed the intensity level by a few more orders of magnitude and helped usher in a new type of laser-matter interaction that is referred to as high-intensity laser physics. In this talk, I will discuss the differences between nonlinear optics and high-intensity laser physics. The development of CPA and why short, intense laser pulses can cut transparent material will also be included. I will also discuss future applications.

MHD waves – slow, Alfvén and fast – lose their distinctiveness in certain regions of a stratified plasma, such as solar or stellar atmospheres. We discuss all three mode conversion processes, fast/slow, fast/Alfvén and slow/Alfvén and how they are affected by atmospheric structure, magnetic field orientation, and partial ionization. We also present some simulations of fast/slow coupling in shock waves.

El telescopio solar EST, con su espejo primario de 4.2 m, será uno de los mayores telescopios solares del mundo. Uno de los instrumentos que se instalarán en EST es EMBER (EST spectropolariMeter Based on slicer-mirrors for the near-infraRed). El instrumento es un espectropolarímetro de alta resolución espacial y espectral que trabajará en el infrarrojo cercano (1.0 a 1.8 micras). Tendrá una resolución espacial de 0.1’’ y observará un campo de visión (FoV) simultáneo de 10’’ x 10’’. Para poder cubrir ese FoV, llevará incorporada una Unidad de Campo Integral (IFU) basada en espejos rebanadores. Su espejo rebanador, situado en el foco, secciona la imagen. Después un sistema óptico reorganiza los haces generando, en este caso, varias rendijas de salida, que serán la entrada al espectrógrafo. En esta charla, se presentará un diseño conceptual de la IFU que está basado en la unidad actualmente instalada en el espectrógrafo GRIS del telescopio solar GREGOR. La mayor diferencia está en el gran campo de visión que le llega, pasando de un slicer de 1.8 x 3 mm con 8 rebanadas a uno de 10 x 10 mm con 400 rebanadas, lo que supone un gran reto para su diseño y fabricación.

Stellar models are a crucial ingredients for a pletora of fundamental research fields in Astrophysics: from the planet-host stars to Galactic Archaeology, from fundamental Physics to the study/understanding of far-away unresolved galaxies, from helio/astero-seismology to exotic stellar objects such as Blue Stragglers, Blue Hook stars, millisecond pulsars, supernova progenitors, etc. There are various stellar model libraries available in the literature, each one with its own pro and cons; some of them being more suitable for specific research topics. In any case, the use of any stellar model library should not ignore the knowledge of the limitations affecting each library. In this talk, we present the BaSTI_IAC stellar model library that has been developed in the context of a strong collaboration with staff members of the IAC; we discuss the main characteristics of this library, and make a comparison with some of the most commonly used model libraries available in literature. We present also some important recent applications of the BaSTI_IAC library to various scientific problems. At the end we discuss the ongoing effort to improve/extend the library as well as our wish to include additional stellar and sub-stellar mass ranges, with hope to foster new collaborations/synergies with colleagues@IAC.

The elusiveness of neutrinos is most renowned for their ability to penetrate and traverse vast amounts of matter without disturbance. While this very same property makes neutrino detection one of humanity’s most remarkable achievements, recent and forthcoming advancements in instrumentation continue to enhance our ability to harness neutrino-based information as a fundamental tool. This, in turn, provides unique insights into some of the most essential mysteries of the Universe. For instance, shortly after their discovery in the 1950s, neutrinos offered direct confirmation and deeper understanding of the fundamental fusion processes powering the Sun. Today, they are indispensable to our quest for a comprehensive understanding of Earth’s interior, the depths of the Sun, supernovae, high-energy cosmic ray emissions, and the early Universe’s structure following the Big Bang. Furthermore, neutrinos may play a crucial role in our pursuit of the origins of matter and the search for new physics beyond the Standard Model.
In this colloquium, I will highlight some of the most remarkable achievements in neutrino science to date, as well as emerging advancements that have the potential to complement all other cosmic probes — most notably, those within the IAC’s leadership in this field.