Recent Talks

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.

Durante la visita a México, el IAC ha realizado la integración del multiplexor dentro del criostato, enfriado y pruebas del software de mecanismos, control de temperatura del detector y control del detector en si mismo, obteniendo imágenes de prueba y curvas de enfriamiento y calentamiento del criostato.

Durante el resto de la visita, se integró el detector de Ingeniería y siguieron las pruebas de software para asegurar el correcto funcionamiento de los distintos módulos desarrollados.
También se hablará de los avances en el MAD, MCT y control automático de temperatura del detector.

En este seminario se presentan los componentes software del sistema de control GCS que controlan el encendido de los diversos componentes de los armarios de los instrumentos y también el control de temperatura de los armarios.

Albeit rare in absolute numbers, massive stars are shaping our cosmic history as they are connected to many astrophysical key processes. Commonly defined as stars with an initial mass of more than 8 times the mass of our Sun, massive stars are the progenitors of black holes and neutron stars, reaching all nuclear burning stages before eventually undergoing their inevitable core collapse. In their comparably short life, these luminous objects have an enormous impact on their galactic environment, enriching the surrounding medium with momentum, matter, and ionizing radiation. This so-called "feedback" of massive stars is a building block for the evolution of galaxies, initiating and inhibiting further star formation. In the "afterlives" of massive stars, black holes and neutron stars can merge with each other, giving rise a to Gravitational Wave events. Yet, overall textbook picture typically drawn of massive stars is rather sketchy and often also at odds with observational constraints. New frontiers such as the strong metal-enrichment in high-redshift galaxies discovered by JWST or the black hole statistics obtained from Gravitational Waves only add further pieces to the enigmatic massive star puzzle.

For a better understanding of massive stars, it is essential to properly determine their parameters and feedback. For young and hot massive stars, many properties are only accessible via spectroscopy. Their quantitative measurements and predictions rely on suitable models for stellar atmospheres, which requires sophisticated simulations to account for their non-equilibrium conditions and strong stellar winds. In this talk, I will introduce the techniques and challenges of atmosphere modelling for hot, massive stars and their winds. Afterwards, I will present a selection of the research efforts within my group demonstrating the range of empirical and theoretical applications of modern non-LTE stellar atmosphere models, such as the analysis of important landmarks of massive star evolution, the search for "hidden" post-interaction binaries, or theoretical insights on radiation-driven winds. Finally, I will give an outlook on current observational challenges and theoretical insights from 2D and 3D simulations raising a new need to reconsider some of the current paradigms in massive star atmosphere modelling.

Strongly lensed supernovae are extremely rare and powerful probes that can give insights into high-redshift supernova physics, substructures in massive galaxies, and the expansion rate of the Universe. Currently, the lensed supernova field is at a turning point, as we will go from a handful of present discoveries to several hundreds per year with the advance of the next generation of telescopes. In this talk, I will present the current state of the lensed supernova field and future developments. Beginning with the discovery story of ‘SN Zwicky’, a lensed type Ia supernova found with the Zwicky Transient Facility, I will take you on a visual journey, using beautiful observations to highlight our discoveries about SN Zwicky, its exceptionally light lens galaxy, and implications for stellar microlensing. Finally, we will look ahead at the upcoming Vera Rubin Observatory and how it will help us discover more lensed supernovae and refine our understanding of the Universe’s expansion.

The nature and origin of sub-Neptune-sized planets is arguably the hottest debate in the field of exoplanets nowadays. While absent in the Solar System, they are the most common planet type in the Galaxy. Multiple models (gas dwarfs, water worlds, Hycean planets) appear to explain current observational evidence from mass-radius measurements and demographic analyses. JWST promises to break those degeneracies, but the first results are just getting published. In this talk, I will give an overview of the questions surrounding the origin of the "Radius gap", recent discoveries of benchmark sub-Neptune systems, new developments on the modelling of the internal structure of these planets, and how the ERC-funded project "THIRSTEE" aims to answer the questions surrounding this ubiquitous but mysterious population.

La fabricación aditiva (AM) engloba un conjunto de tecnologías que permiten pasar de un modelo 3D a componentes fabricados, creándolos capa a capa hasta completar la pieza. Entre las ventajas de la AM, las que más se aplican a la instrumentación astronómica son la complejidad y consolidación de las piezas, la adición de funcionalidades, la libertad de diseño y la capacidad de aligerado. El objetivo de esta charla es presentar todo el proceso de obtención de prototipos de espejos metálicos (y cerámicos) desde el inicio: desde el diseño conceptual, hasta los tests sobre las probetas de espejos aligerados.

Relativistic jets are amongst the most important and powerful phenomena in astrophysics, and yet also amongst the least understood. Most well known in the context of supermassive black holes in active galactic nuclei (AGN), relativistic jets are also the underlying mechanism behind gamma-ray bursts (GRBs) and LIGO neutron star merger afterglows, and a fundamental component of Tidal Disruption Events. Stellar mass (<20 solar masses) black holes and neutron stars in binary systems, known as 'X-ray binaries' (XRBs), are the local, lower-mass, and hence faster-evolving analogues to AGN, as well as being the direct descendants of GRBs and on the same mass scale as the LIGO merging BH. The near scale-independence of accretion and jet formation with BH mass, theoretically expected and observationally established, demonstrates that what we learn from XRBs can be applied to more massive systems such as AGN. In the past 6 years observations with the MeerKAT telescope have revolutionised our understanding of these jets, allowing unprecedented investigations into the power of black hole jets, measured as we track them decelerating and transferring their launch kinetic energy to the ambient ISM. These observations have also increased our sample size sufficiently that we can now make definitive statements about the relation between jet speed, jet precession, the nature of the compact object, and the connection to black hole spin.

Mass-loss of massive stars is an uncertain, but very important part of stellar evolution, as massive stars lose a significant amount of mass even in their main sequence. Currently, stellar evolution models often include mass-loss in the form of a mass-loss prescription based on the Vink et al. 2001 models. This prescription includes a steep increase in mass-loss for stars cooler than 25000K referred to as the bi-stability jump. The existence of this jump has been contentious for a long time, with multiple observational studies searching for the jump. However, it has never been observed when studying a sample of stars crossing this temperature regime, recently this includes studies with a very large sample size such as the IACOB project. Due to a degeneracy between the clumping behaviour of the wind and the mass-loss rate when looking at optical spectral lines only, it is not possible to measure exact mass-loss rates, but instead you obtain a mass-loss rate convolved with the clumping factor. Thanks to the ULLYSES program and the Xshoot-u optical follow up we now have a sample of B-giants in the LMC and SMC for which we have both optical and UV spectroscopy. UV spectroscopy not only gives us access to important wind diagnostics such as terminal wind speed, but also gives us the ability to determine clumping properties independent from mass-loss rates. The increased complexity we need to include in our models to represent the clumping behaviour does increase the number of free parameters significantly. I will show how we use Genetic Algorithms to fit many parameters at the same time and how we used this method to derive mass-loss rates and clumping properties for LMC and SMC B-supergiants covering the bi-stability jump.