Recent Talks

Dark sirens are sources of gravitational waves (typically mergers of black hole binaries) without an electromagnetic counterpart. The gravitational waveform measured by our detectors allows us to infer the distance (not the redshift) to those sources, and with the new generation of detectors such as the Einstein Telescope, the uncertainty in their angular position and distance will decrease dramatically. In this talk I will show that by correlating dark sirens and galaxies we can directly draw the Hubble redshift-distance relation, with minimal assumptions about the underlying cosmology. This allows for a direct measurement of the Hubble parameter, free of the systematics of standard sirens and without the model dependence of the Planck constraint, which can achieve an accuracy of 4% with run 5 of the LIGO-Virgo-Kagra network of gravitational wave detectors, and less than 1% with the future facility Einstein Telescope.

We present our results from observing the occultation of Betelgeuse by asteroid (319) Leona on December 12,2023, using a cutting-edge 64 x 64 pixel Single-Photon Avalanche Diode (SPAD) array mounted on a 10-inch telescope at the AstroCamp Observatory in Nerpio, Southeast of Spain, located just a few kilometers from the center of the occultation shadow path. This study marks a remarkable advancement in applying SPAD technology in astronomy. The SPAD array's asynchronous readout capacity and photon-counting timestamp mode enabled us to achieve a temporal resolution of I microsecond in our light curve observations of Betelgeuse. The data analysis addresses challenges inherent to SPAD arrays, such as optical cross-talk and afterpulses, which cause the photon statistics to deviate from a Poisson distribution. By adopting a generalized negative binomial distribution (NBD) for photon statistics, we accurately describe the observational data. This approach yields an optical cross-talk estimation of l.OlVo in our SPAD array and confirmed a negligible impact of spurious detected events from afterpulses. The meticulous statistical examination of photon data underscores our SPAD-array's exceptional performance in conducting precise astronomical observations. The observations reveal a major decrease in Betelgeuse's intensity by 77.78Vo at the occultation's peak, allowing the measurement of Betelgeuse's angular diameter to be 57.26 mas in the SDSS g-band. This measurement was obtained by employing a simplified occultation model and considering the known properties of Leona. This work not only demonstrates the potential of SPAD technology in astronomy but also sets a new standard for observations of transient celestial events, offering a precious public dataset for the astronomical community.

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.

A prediction of the standard LCDM cosmological model is that dark matter (DM) halos are teeming with numerous self-bound substructure, or subhalos. At small scales, subhalos may host no stars/gas at all and thus may not have visible astrophysical counterparts. The existence and precise properties of these ‘dark satellites’ represent important probes of the underlying cosmological model. Also, they may play a key role on the search for DM via its annihilation products. In this talk, I will present current numerical work to characterize the subhalo population with unprecedented detail, and will discuss on the importance that dark satellites may have for DM searches with present or future gamma-ray observatories. I will then summarize the recent efforts we made to search for them in gamma-ray data and to set constraints on the nature of the DM particle using these elusive targets.

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.

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.