Recent Talks

Stars and planets formed within the same molecular cloud are inextricably linked in their composition. Alpha-process elements shape planetary cores and atmospheres, with studies showing that key elemental ratios (e.g. Fe/Si, Mg/Si) in planets reflect those of their host stars. While correlations between stellar chemical abundances, planet occurrence, mass and orbital properties have been suggested, definitive confirmation remains difficult due to the subtlety of these trends. Large, homogeneous, high-precision spectral datasets are essential to uncover these relationships. Bright stars (V < 11 mag), such as PLATO's priority-one targets, provide an ideal sample for high-quality stellar and chemical abundance measurements and are expected to yield thousands of new planetary discoveries in the coming years. However, modern multi-object spectroscopic (MOS) surveys often exclude these stars due to their low on-sky density, leading to inefficiencies in conventional observing strategies. The WEAVE-TwiLight Survey (WTLS) solves this problem by introducing a groundbreaking observing mode that optimises efficiency by combining multiple fields into a single fibre configuration. It is expected to produce a homogeneous spectral dataset of ~6,000 bright stars, tailored to probe the chemical relationships between host stars and their planets. In this talk, I will give a general overview of host-star planet relations and discuss the status of the upcoming WEAVE-TwiLight Survey.

El uso de herramientas de simulación en óptica adaptativa es fundamental para definir requisitos técnicos, comparar configuraciones ópticas, evaluar algoritmos de reconstrucción y desarrollar estrategias de control, con el objetivo de optimizar el rendimiento del sistema. Un simulador de AO debe ser eficiente computacionalmente y flexible para el prototipado de nuevas configuraciones y esquemas de control.

En este seminario, se presentará OOPAO, un simulador desarrollado en Python por Cédric Heritier (ESO, 2023), y se discutirán las mejoras implementadas por el equipo de EST para adaptarlo a aplicaciones en el caso solar y optimizar su rendimiento computacional.

One of the most fundamental questions in astronomy is how stars, the building blocks of the Universe, form. We generally understand that stars emerge from dense regions within molecular clouds, called prestellar cores, which collapse under gravity to form protostars, but many details of this process remain elusive. Despite significant advances in instrumentation and modelling, we still lack a complete understanding of how stars and planetary systems develop. A crucial piece of this puzzle lies in the protostellar phase, particularly the accretion process responsible for stellar mass growth at the early and more embedded stages of star formation. In this talk, I will review the current state of knowledge on accretion, presenting my work on last observational results of the early stages of star formation and discussing their implications for the broader star and planet formation scenario. 

Durham Adaptive Optics (DAO) is a powerful and flexible software solution for adaptive optics systems.  DAO enables real-time correction of wavefront distortions caused by atmospheric turbulence and optical aberrations, improving the image quality of ground-based telescopes. DAO takes a hardware-agnostic approach to processing pipelines, supporting distributed heterogeneous compute environments. Its high flexibility allows seamless integration with various hardware systems and configurations, accommodating different wavefront sensors (such as Shack-Hartmann and pyramid sensors), actuators (including deformable mirrors, tip-tilt mirrors, and spatial light modulators), and other components.

The presentation will cover the software's flexible architecture, which enables it to be integrated with a variety of hardware systems and configurations. We will showcase DAO’s user base and how DAO has been used to solve their adaptive optics real-time control needs. These examples will demonstrate DAO’s efficient data handling, parallel processing techniques, low latency, and minimal jitter, whilst emphasising its capacity to scale to AO systems of all size, from laboratory-based research projects to ELT-scale facility class systems.

In order to understand galaxy growth evolution, it is critical to constrain the evolution of its building block: gas. Mostly comprised by Hydrogen in its neutral (HI) and molecular (H2) phases, the latter is the one mostly directly associated to star-formation, while the neutral phase is considered the long-term gas reservoir. Both phases are difficult to detect directly either due to high excitation temperatures or low transition probability. As a result, while HI direct observations have been limited to the local Universe and extended to high redshifts when seen in absorption, H2 has been traced indirectly via tracers, either Carbon Monoxide (CO) rotational transitions, atomic Carbon fine structure transitions, or dust emission at (sub-)mm wavelengths. However, the latter best tracers the combined content of HI and H2 masses. In this work (Messias et al. 2024), we make use of an empirical relation between dust emission at millimeter wavelengths and total gas mass in the inter-stellar medium (M_HI plus M_H2) in order to retrieve the HI content in galaxies. We assemble an heterogeneous sample of 335 galaxies at 0.01<z<6.4 detected in both mm-continuum and carbon monoxide (CO) low-J transitions. More specifically, a blindly selected sub-sample had a special focus given its suitability to retrieve HI cosmological content when the Universe was ~2-6 Gyr old (1<z<3). Overall, we find no significant evolution with redshift of the M_HI/M_H2 ratio, which is about 1–3 (depending on the relation used to estimate M_HI). This also shows that M_H2-based gas depletion times are underestimated overall by a factor of 2–4. Compared to local Universe HI mass functions, we find that at least the number density of galaxies with M_HI>1E10.5 Msun significantly decreased since 8–12 Gyr ago. The specific sample used for this analysis is associated to 20-50% of the total cosmic HI content as estimated via Damped Lyman-alpha Absorbers. In IR luminous galaxies, HI mass content decreases between z~2.5 and z~1.5. Finally, the results obtained in this work allow us to report source detection predictions for SKA1 surveys and what is the most suitable strategy to detect HI at cosmic noon.

Wavefront sensing and adaptive optics, techniques developed from astronomy, have made their way to the ophthalmology practice. Correcting the aberrations of the eye has allowed unprecedented resolution to resolve fine structure in the human retina. On the other hand, wavefront sensing has become a ubiquitous technology to assess the optical quality of the eye and advanced refraction. Visual simulators, based on adaptive optics, allow patients to preview the world with prospective corrections and select the contact lenses, intraocular lenses or corneal refractive surgery pattern that best fits their visual function and perceptual preference

Supernovae represent the explosive death of a star. There is a small group of core-collapse supernovae whose peak luminosity in the light curve is so high that it cannot be explained by conventional models. Therefore, it is necessary to consider alternative boosting mechanisms to understand their origin.  In this talk, I will present the characterization of the largest sample of hydrogen-rich superluminous supernovae (SLSN II) available to date. I will discuss the possible mechanisms responsible for the observed features and the minimum requirements needed to conduct similar analyses using data from the Legacy Survey of Space and Time (LSST) of the Vera C. Rubin Observatory.

The atmosphere of a rocky or icy moon is the interface between its surface and its orbital environment, and encodes information about both its interior processes and its interactions with its host planet’s magnetosphere. Among the outer Solar System’s major moons, atmospheres range from the tenuous, sputtered O2 atmosphere of Europa to the dense, organics-laden atmosphere of Titan. Obtaining a complete picture of the atmospheric composition and dynamics requires a multi-wavelength approach, as different observing techniques are sensitive to different chemical components, altitudes, and excitation mechanisms. This talk will present recent observations of the atmospheres of satellites in the Jupiter and Saturn systems from observatories including HST, JWST, Keck, and ALMA, and will discuss how multi-wavelength approaches are giving us a more complete understanding of the atmospheres of these moons and enabling progress on key questions.

Strong gravitational evidence at galactic, extragalactic and cosmological scales exists to believe that most of the matter in our Universe, i.e. up to ∼85% of the total, is dark and non-baryonic. Yet, this dark matter (DM) has not been directly detected. Some of the most preferred scenarios suggest that DM consists of Weakly Interacting Massive Particles (WIMPs), which interact mostly gravitationally with baryonic matter.

The fundamental laws of physics known to date suggest that equal amounts of matter and antimatter should have been produced, and annihilated, during the Big Bang. Yet, observations show that antimatter is present at most in tiny traces is the Solar System and Milky Way neighbourhood, and that a perfect symmetry between matter and antimatter is ruled out at the scale of the entire Universe. In this seminar I will present a review of the observations that characterise the matter-antimatter asymmetry in the Universe and I will briefly outline some theories that try to explain it. I will conclude by presenting some recent observational results that may indicate cracks in the current paradigm that the Universe has been free of antimatter domains since its early phases.