Recent Talks

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

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.

The evolutionary connection between thick and thin disks is still a matter of debate, while observations of high-redshift galaxies have recently shown that stellar disks of various thicknesses emerged very early in the universe. Their diversity seeded the large variety of properties observed in the local universe. Zooming into the spatially resolved stellar populations of very nearby galactic disks traces the story of spiral and lenticular galaxies, from the early stages to recent times. I will present my contribution on this topic, combining high-quality integral-field spectroscopy (IFS) observations of edge-on galaxies with high-resolution numerical simulations.Our recent studies have revealed different stellar populations of nearby thick disks in different types of galaxies, with different star-formation rates (SFRs), suggesting that they result from different evolution histories. The sharp transition, in earlier-type disk galaxies, between old, metal-poor and alpha-enhanced thick disks, and younger metal-rich thin disks, suggests that they formed in two distinct evolution phases. Highly star-forming late-type galaxies, with little differences between relatively young and metal-poor thick and thin disks, suggest a slower upside-down formation. I will finally compare these observations with AURIGA zoom-in cosmological simulations of Milky Way-mass galaxies, revealing one other piece of the puzzle: the connection between the fraction of in-situ and ex-situ stars and stellar-population properties. In these simulations, younger thick disks are explained by later and more massive mergers. These not only contribute younger stars from accreted satellite galaxies, but also large amounts of gas to extend off-plane star formation in time.

n this talk, we will explore innovative approaches to dark matter detection, building upon the foundations of conventional methods. We begin with a concise overview of established detection techniques before delving into direct and indirect detection strategies. For indirect detection, we analyze X-ray data from INTEGRAL/SPI and cosmic-ray positron measurements from AMS-02, leveraging these observations to impose stringent constraints on the decay of dark photon dark matter. In the context of direct detection, we highlight the potential of low-threshold detectors for probing boosted dark matter. Finally, at the intersection of indirect and direct detection, we discuss the novel concept of utilizing celestial objects as natural dark matter colliders and detectors, offering a unique avenue to constrain interactions between dark matter and the Standard Model.