Stellar-mass black hole candidates have been identified in several star clusters through accretion signatures and radial-velocity variations of companion stars. These detections likely trace much larger, underlying populations of black holes retained in clusters. I present comparisons between dynamical star cluster models and observations of a range of star clusters, supporting the view that substantial black hole populations in clusters are common.

Using population-synthesis models of dynamically formed binary black holes (BBHs), I demonstrate how BBH formation in star clusters contributes significantly to the population of gravitational-wave sources. When combined with recent LIGO–Virgo–KAGRA results, these models indicate that dynamical BBH formation is particularly important for systems with primary masses above ~40 M☉, potentially filling the so-called pair-instability mass gap. Finally, I discuss prospects for detecting intermediate-mass black holes (IMBHs) formed in globular clusters with future gravitational-wave observatories such as DECIGO, the Einstein Telescope, and LISA.

Neutron-star low-mass X-ray binaries (NS-LMXBs) are binary systems composed of a NS and a low-mass companion star. In these systems, matter transferred from the companion star via Roche-lobe overflow forms an accretion disc around the NS, releasing gravitational energy as radiation, especially in the X-ray band. In addition, the matter accreted on top of the NS surface can sometimes undergo thermonuclear runaways and produce explosions, known as type-I X-ray bursts. On 2025 June 23, the Einstein Probe discovered a new X-ray transient, later designated EP J1711−3332, during its wide-field monitoring. Follow-up observations quickly revealed multiple type-I X-ray bursts and clear X-ray eclipses. Moreover, the bursts were observed to repeat quasi-periodically during an observation with NuSTAR, identifying the source as a new “clocked burster”, a rare subset of NS-LMXBs.

In this talk I will present the results of a detailed spectral-timing analysis of EP J1711-3332 with data collected by multiple instruments including Einstein Probe, NuSTAR and ULTRACAM. I will also give a general introduction to the Einstein Probe mission.

HAYDN is one of the ten mission concepts proposed to ESA’s M-class call (M8) after its Step-1 selection. It is designed to revolutionise our understanding of stellar structure and evolution through high-precision, space-based asteroseismology in dense stellar fields, including clusters. By performing continuous photometric monitoring of stars in these dense stellar fields, HAYDN aims to map stellar interiors across a wide range of ages, masses, and chemical environments—providing unprecedented constraints on stellar physics, Galactic evolution, exoplanet’s formation, and the formation history of the Milky Way, for naming some of the HAYDN’s science cases. In this talk, I will present the scientific motivation, mission architecture, and observational strategy of HAYDN, as well as the unique diagnostic power that seismic measurements offer for probing stellar structure in environments inaccessible to current missions. I will also give an overview of the current status of the proposal, its evolution from ESA’s M7 cycle to the ongoing M8 selection process, and the major technical milestones achieved so far. A significant part of the talk will highlight the Spanish contribution to HAYDN, including leadership roles in mission science, coordination of key working groups, and involvement in the design of the payload and data processing pipeline. Spain is currently the second-largest contributor to the project, with active participation from several national institutes and universities. Finally, I will outline the opportunities HAYDN opens for the Spanish community—from synergies with ground-based facilities to participation in science preparation activities—and discuss how this mission could strengthen Spain’s strategic presence in future ESA space-astrophysics programmes.

Accreting white dwarfs (AWDs) provide an accessible laboratory for studying accretion physics and geometry across a wide range of physical scales. Their rapid optical variability, from stochastic flickering to quasi-periodic oscillations (QPOs), makes them ideal targets for high-cadence missions such as Kepler and TESS, allowing the structure of accretion flows to be probed in real time.
In the first part of this talk, I will show how broad-band optical variability in AWDs reveals accretion geometry from the inner magnetosphere to the outer accretion disc. Using models of propagating accretion-rate fluctuations, I will demonstrate how accretion in AWDs is linked directly to X-ray binaries and active galactic nuclei. I will also present the discovery of a new class of strong optical QPOs in AWDs, best explained by magnetically driven disc precession, establishing a clear, scale-invariant connection to accretion onto neutron stars and black holes.
In the second part, I will extend this geometric view beyond the disc by presenting the discovery of a resolved bow shock around the strongly magnetic, disc-less accreting white dwarf 1RXS J052832.5+283824. The properties of this bow shock rule out standard formation scenarios and instead point to a powerful, persistent, likely magnetic energy-loss mechanism that may influence long-term binary evolution.

I revisit the luminosity function of compact HII regions in the framework of the inertial-inflow scenario of massive star formation, where massive stars assemble over extended, mass-dependent timescales. The comparison of the luminosity function of compact HII regions with that of OB stars has been used to infer relatively long lifetimes of compact HII regions, confirming their classical ''lifetime problem''. Here I show that once stellar growth during the ionizing phase is included, the luminosity function comparison provides instead an important constraint on massive-star formation timescales. I illustrate the principle with a simple analytic model and then use a Monte-Carlo approach to forward model the two LFs starting from a model IMF. The observational constraints are improved by deriving a revised luminosity function of compact HII regions from the Red MSX Source survey, and a new OB-star luminosity function from the combination of the ALS-III, GOS and Gaia DR3 catalogs. I find that, in this scenario, much longer lifetimes of compact HII regions are inferred, which are reinterpreted as strong evidence of an extended formation time of massive stars, rather than an expansion timescale problem. The joint LF constraints imply a growth law of massive stars consistent with the inertial-inflow model. The revised OB-star LF exhibits a statistically significant steepening above 25 Msun, while the steepening in the HII-region LF happens at a lower mass, also consistent with the inertial-inflow model.

The formation and evolution of galaxies depend on galaxy properties and environment, varying from dwarfs to massive ellipticals, from dense cluster regions to the diffuse field, and across cosmic time from the early universe to the present day. As a result, galaxy formation and evolution is a complex process that cannot be fully understood by observations or simulations alone. Therefore, close collaboration between observations and simulations is essential, and scaling relations are one of the most commonly used tools for comparing observational results with simulations. In this talk, I will focus on low-redshift galaxies and two observational parameters: color gradients and galaxy size. I will show why color gradients are promising probes that can provide additional insights into galaxy formation and evolution. I will also discuss how the environment affects the size–mass relation. Finally, I will briefly mention the promising future of studies of stellar haloes in the outskirts of galaxies.

Spain will deploy and operate a constellation of eight low Earth orbiters for Earth monitoring in the context of a collaboration with Portugal. The mission, known as Atlantic Constellation, consists of sixteen satellites (eight provided by each Country) with capacity to provide optical multi-spectral images, ocean ship information (listening to the mandatory messages transmitted by vessels) and internet of things operations. Additionally, the Spanish contribution also will provide GNSS reflectometry data. The Spanish contribution to the mission is managed by ESA, which selected the consortium led by Open-Cosmos through a competitive tender. The Earth Observation Group at ICE-CSIC are the partners of the consortium responsible of the GNSS reflectometry payload and products. The seminar will describe the mission and our role in it.

Five ICE second- and third-year PhD students will provide short, 8+2 minuts presentation on their current proyects and advancements.

Gravity rules physical phenomena at large scales, from the Solar system to the size of the observable universe. General Relativity is the simplest theory that, despite challenges from better and better experiments and observations, can accommodate all of them so far, independently of whether certain physical phenomena as dark matter and dark energy lack a proper integration in our existing theoretical framework. General Relativity is also the last classical theory of a "fundamental" interaction and so far the only one lacking a quantum description. In this talk, to celebrate its 110th anniversary, I will discuss the main ideas on which the theory was built and I will summarize its experimental status and the future prospects to challenge it.

The framework has been strongly shaped by the needs of the Cherenkov Telescope Array Observatory (CTAO), where coordinating multiple telescopes, handling rapid-response observations, and managing complex subarray behavior demand highly adaptive scheduling methods. Beyond CTAO, STARS is also used in missions such as ESA’s ARIEL and PLATO and at the Montsec Observatory, each contributing its own requirements to the system’s evolution.

Both applications rely on ultra-precise laser ranging interferometers and accelerometers. I will discuss the role of laser frequency in ranging measurements, and present accelerometers technology based on opto-mechanical ones, which will be tested in space in GRATTIS, a NASA-funded technology demonstrator mission launching in February 2027. I will also present our developments for the NASA Habitable World Observatory based on LISA technology efforts.

Gravitational-wave astronomy has entered a mature observational phase, with the fourth Gravitational-Wave Transient Catalog (GWTC-4.0) reporting nearly a hundred new detections of compact binary coalescences from the first half of the LIGO-Virgo-KAGRA O4 observing run. In this talk, I will begin with an introduction to how current gravitational-wave detectors operate and how astrophysical signals are identified and characterized. I will then present the main highlights of the new catalog, including the inferred masses and spins of the detected sources, the population properties of binary black holes, and several particularly interesting individual events. Finally, I will discuss the crucial role of waveform models—our theoretical predictions for the expected gravitational-wave signals—in both detection and parameter estimation, and how recent modeling developments are improving the accuracy of current and future analyses.

Stellar magnetic activity has long been recognized as a fundamental process shaping the environments of stars like our Sun. Despite its maturity, the field of stellar activity has witnessed a remarkable surge in discoveries over the past decade. Interestingly, it happened largely thanks to the missions and programs whose primary goal was not to study stars themselves, but to characterize the exoplanets they host. Direct observations of exoplanets remain limited, meaning that much of exoplanetary science currently depends on precise measurements of host stars. Alongside planetary signals, these observations often reveal signatures of stellar magnetic activity. These signatures are both a blessing and a curse: on the one hand, they allow getting invaluable insights into stellar magnetism, while on the other hand, they directly interfere with the detection and characterisation of exoplanets. In this talk, I will review stellar-activity signatures in exoplanet data and our first attempts to understand them.

Strongly lensed supernovae are excellent laboratories for inferring cosmological parameters and understanding explosive astrophysics. The lensing magnification acts as a "gravitaitonal telescope" to amplify the light of distant supernovae and study them in great detail - which is important to constrain the systematics in dark energy inference with the Hubble diagram - a very timely problem given the hints that dark energy maybe evolving with cosmic time. Moreover, strongly lensed supernovae are also an independent probe of the Hubble Constant - the value of which is heavily debated, as the local Cepheid distance ladder is discrepant with the early universe inference. In this talk I will summarise results from our recent paper on possible interpretation of deviations from dark energy as a cosmological constant in light of unknown astrophysical or instrumental effects. I will also show results from recent work on detailed predictions for the precision of lensed supernova time-delays and the importance of model complexity in minimising bias from time-delay cosmography.

My research explores how galaxy interactions and environments can shape star formation and trigger active galactic nuclei (AGN). Using photometric and spectroscopic surveys, I have studied pairs, tidal features, and satellites, highlighting their role in galaxy evolution. I will review these results and point to the next step: using data science and deep learning to tackle these questions with Big Data from DESI and SDSS.

Dust is ubiquitous in the Universe and affects the observations of many astronomical sources. The study of dust extinction and reddening towards supernovae and their host galaxies touches upon a wide range of topics: supernova progenitors and their explosions, local and global interstellar medium properties in galaxies, and systematic biases in type Ia supernova cosmology affecting the measurement of the Hubble constant and of the dark energy equation of state. In this talk, I review the current state of extinction studies towards supernovae and their environments, and present the multiple techniques we are using which include polarization and integral field spectroscopy compared to radiative transfer simulations.

This presentation tries to explore the application of GNSS in studying earthquake cycle deformation to understand our dynamic Earth. Beginning with a comparison of the Earthquake hazard risks faced by China and Spain, the talk will introduce the role of GNSS in the Earth sciences, with a special focus on its application in monitoring crustal deformation and the earthquake cycle. Finally, connecting with the work of the Earth Observation group at ICE, the presentation will look ahead to emerging applications, including the use of ground-based GNSS reflectometry for groundwater monitoring and the application of GNSS Radio Occultation to detect changes in the ionosphere.

In the coalescence of neutron stars the bulk viscous dissipation offers a potential opportunity to infer properties of neutron star matter by estimating its effect on the gravitational wave emission. To this end, we compute the bulk viscosity and the relaxation times in unpaired quark matter with electrons considering the electroweak processes allowed in the neutrino-transparent regime at low temperatures. Using the equations of state of bag models and perturbative QCD, we analyze the dependence of our results on the density, temperature and strange quark mass. Finally, we study relevant phenomena in the merger of binary compact stars where the bulk viscosity plays a significant role. First, the damping of baryon density oscillations in quark matter and its importance in the postmerger phase after the collision of two neutron stars if deconfined matter is achieved in the process. Further, the tidal heating induced by the companion in the binary inspiral of strange quark stars and its effect on the gravitational wave form.