SN 1987A in its third decade imaged by the Hubble Space Telescope: Evolution of the ejecta and equatorial ring
Sophie Rosu (KTH Royal Institute of Technology, Stockholm, Sweden)

The spatially resolved view of the transition into a young supernova (SN) remnant offered by SN 1987A makes it the most thoroughly studied SN so far, from ground to space, at all wavelengths. Its evolution has notably been followed by the Hubble Space Telescope (HST) since its launch in 1990 with an excellent spatial resolution.

We present the recently (2022) acquired HST imaging observations of SN 1987A. For the first time since 2009, the observations cover the entire optical domain between 200 and 1100 nm. We make use of these and earlier observations to study the recent evolution of the spectral energy distribution (SED) and morphology of all parts of the system. We also use the annual imaging in the blue and red filters to provide lightcurves for the different parts of the system.

The recent imaging provides us with a spatially resolved view of both the freely expanding ejecta and the interaction of this latter with the circumstellar medium, revealing the asymmetric ejecta structure in increasingly greater detail.

We observe a decay in the lightcurve of the equatorial ring (ER), explained by the continuous fading of the hotspots that started ∼8000 days after the explosion. A noticeable increase in the ejecta flux is observed until day ∼ 11000, after which the flux seems to flatten around a constant value, owing to the X-ray input coming from the ER.

We do not observe any clear evidence for a point source at the center of the ejecta that would be associated with the direct detection of a compact object. We discuss the implication of our findings in terms of both the energy sources contributing to the ejecta emission and limits on the compact object.

Physics opportunities of CEvNS experiments
Diego Aristizabal Sierra (Santa Maria U., Valparaiso)

Experimental facilities that study coherent elastic neutrino-nucleus scattering, or CEvNS (pronounced sevens), provide a rich environment for precise measurements of Standard Model parameters and searches of new physics. In this talk, I will discuss a few aspects of this program involving solar neutrinos and third-generation dark-matter detectors as well as directional detectors in the Fermilab neutrino beamlines.

Future "firsts" in gravitational-wave observations
David Keitel (IEB, Mallorque)

Beyond the highly successful detection efforts for compact binary coalescences (CBCs), gravitational-wave astronomy also comprises other long-standing search efforts, such as those for continuous waves (CWs) from individual spinning neutron stars. Furthermore, the field is diversifying with new searches for additional astrophysical effects and source types.

I will summarise some recent progress towards three such potential "next first detections":

• . The search for signatures of gravitational lensing on CBC signals, where heavy masses along the signals' long voyage to Earth can magnify, multiply or deform them. Here I will focus in particular on recent work regarding the effects of waveform systematics and Bayesian sampler choices, which are crucial to understand for making robust detections.
• . A wide range of searches pursued within the LVK collaboration for known or unknown neutron stars as CW emitters, or even for more exotic sources involving dark matter.
• . Searches for long-duration transient CW-like signals from newborn or perturbed neutron stars, such as binary neutron star remnants or glitching pulsars.

Searching for Evidence of Life Beyond the Solar System with the Giant Magellan Telescope (GMT) and the GMT-Consortium Large Earth Finder (G-CLEF)
Andrew Szentgyorgyi (Harvard-Smithsonian Center for Astrophysics)

Two of the highest priority programs in astrophysics are the discovery and characterization of Earth 2.0 – rocky, Earth-mass exoplanets orbiting Solar-type stars in their habitable zone and the search for biomarkers in the atmospheres of exoplanets in general, The first program is enabled by precision radial velocity (PRV) measurements of the line-of-sight reflex motion of host stars in response to the gravitational influence of low-mass exoplanets that orbit those stars. The search for biomarkers and the characterization of the molecular composition of exoplanets requires extremely high spectral resolution spectrographs on large aperture telescopes. The G-CLEF spectrograph has been designed to provide these capabilities. Before deployment at the GMT, G-CLEF will be delivered to the Magellan telescopes in 2027, to do several pathfinder observational programs that will allow observers to optimize G-CLEF for its delivery to the GMT in 2032. A key project for G@M+MagAO-X will be to resolve and search for O2 in the atmosphere of a habitable zone planet orbiting the star nearest to the Sun – Proxima Cen b. The talk will discuss several aspects of habitability, habitability searches and several technical innovations we will deploy to optimize the Proxima Cen b habitability search.

From heartbeat to heartbreak: the story about eccentric binary systems, tidally excited oscillations and collapsing tidal waves
Piotr Kolaczek-Szymanski (STAR - ULiège)

Currently, no one is surprised by the information that most stars in the Universe reside in binary or even multiple systems. Furthermore, in the case of massive stars (with initial masses >8Msun), we can be almost certain that they have at least one companion, which is most likely also a high- or intermediate-mass star. This means that the evolution of massive stars cannot be studied without taking into account their common binarity. Due to the relatively young age of these systems, many of them still have eccentric orbits. However, significant non-zero orbital eccentricity is not restricted only to young massive stars, but it is also observed in evolved systems, containing red giant(s). The tidal forces acting within them determine the further fate of the system, which under favorable conditions can lead to the stellar merger at very different stages of evolution. Periodically varying tidal potential leads to a series of interesting and significant phenomena from an evolutionary point of view. Among them, so-called heartbeat stars are the prominent ones, due to their characteristic light curves resembling an electrocardiogram. In eccentric binary systems, we can also observe tidally induced oscillations, which directly participate in the evolution of the system's orbit, leading to its accelerated tightening. In some systems, the components pass so close to each other at periastron that the resulting huge tidal deformation cannot return to equilibrium and spectacularly collapses onto the star's surface. During my seminar, I will discuss all these processes, primarily considering the effects of my recently defended PhD thesis and outlining certain research plans for the future.

Linking stellar compositions and planet formation: implications for solar models and stellar surface abundances
Masanobu Kunitomo (Kurume University)

Stars grow by accretion from the protoplanetary disk where planets are formed. Planet formation theory predicts that the composition of the disk gas, and thus of the gas accreted by protostars, must have been variable: the growth and inward drift of dust in the disk leads to the generation of a temporal "pebble wave" of increased metallicity, followed by a phase in which the exhaustion of the pebbles and the formation of planets leads to the accretion of metal-poor gas. How does accretion affect stellar composition? First I will show our solar models with the accretion in the early Solar System which can have a larger central metallicity by up to 5% and thus higher neutrino fluxes, demonstrating that the formation history of the Solar System constitutes a key element in resolving the "solar modeling problem". I will also discuss the implications for chemical peculiarities in other stars: the surface compositions of refractory-poor solar twins, binary systems, and lambda Boo stars.

A Few Topics in Nonlinear and Binary Asteroseismology
Zhao Guo (KULeuven)

Stellar oscillations are not necessarily linear. Some oscillation modes can be weakly nonlinear and may produce daughter modes via parametric instability. This process is a potential amplitude limitation mechanism that determines the final observed oscillation amplitude, as demonstrated in Delta Scuti stars and Slowly Pulsating B stars. Observational signatures of nonlinear mode coupling include periodic amplitude and phase modulations. The behavior of a coupled-mode system can be rich and complex, including period doubling, intermittency, and various pathways to chaos. In some binary star systems with elliptical orbits, tidal forces can directly induce stellar gravity modes, manifesting as luminosity variations at orbital harmonic frequencies. These tidally excited oscillations (TEOs) can mostly be understood within the framework of linear theory. However, nonlinearity can induce non-orbital harmonic TEOs, and we can use these secondary modes to pioneer a new approach to asteroseismology. Finally, I will present another aspect of the nonlinear effect: wave-mean flow interactions. The quadratic terms in the wave equations can modify the background mean flow, and vice versa. We employ a quasi-linear approximation to study the spin-up of the solar core by the ingoing gravity waves induced by a planet, comparing it with direct numerical simulations.

A multimessenger GW-GRB study of the sGRB population and its future developments
Matteo Pracchia (Université de Liège)

The unambiguous joint detection of GRB 170817A and GW170817 has been the long-awaited smoking gun for the association between short gamma-ray bursts (sGRBs) and the merger of binary neutron stars (BNS) systems. The aforementioned sGRB, however, was extremely close and had an unexpectedly low measured luminosity when compared to the other observed sGRBs, suggesting that there is a sub-luminous fraction of the GRB population which is undetected at the usually measured distances.

This work aims to characterize the low-luminosity part of the sGRB population through a multi-messenger GW-GRB Bayesian study. The sGRB population is described via its luminosity probability distribution, modelled through an extension of a broken power law whose parameters have already been constrained through mid-high luminosity sGRB observations. The parameters of this power-law extension, i.e. the low luminosity power index and the low-luminosity cutoff, are constrained through a Bayesian analysis which exploits the results from the modelled GW follow-up analysis of the short GRBs detected during the first three observing runs of the International Gravitational-Wave observatory Network (IGWN).

The results obtained allow us to define the luminosity distribution at lower values for the sGRB population and to give an estimate of the value found for the astrophysical sGRB rate and the joint GW-GRB detection rate for the next IGWN observing runs. There are, nonetheless, some upgrades to the method used for this study that could give a more precise and complete outline of the astrophysical sGRB population.

Seismic/Newtonian noise challenges for third generation gravitational wave detector
Dixeena Lopez (Université de Liège)

The mitigation of various sources of noise that mimic the effect of gravitational waves or constrain the detector's sensitivity is the main challenge for ground-based GW searches. The seismic noises which are active at the low-frequency range below 10 Hz are usually filtered away using seismic attenuation chains and new design implementation. However, the presence of Newtonian noise by the subtler effect of seismic waves and atmospheric effects causes fluctuations in test masses, which mimic the passing of GWs in frequencies below 30Hz.

The Einstein Telescope (ET) is a ground-based underground detector planned to be built in Europe, and observation is likely to start in 2035. The proposed design of ET is a triangular shape interferometer with an arm length of 10 km, which increases the low-frequency sensitivity to almost 1 Hz by the reduction in displacement noise. There will be a ten times improvement in overall strain sensitivity for ET than the current generation gravitational wave ground-based detectors. However, the ET sensitivity is limited by Newtonian noise at low frequencies, and there is no efficient way to shield this effect. In order to improve the low-frequency ET sensitivity to sources like GW memory, one needs to reduce the effect of Newtonian noise using advanced instrumental and data analysis techniques. The accurate models of Newtonian noise, which depends on the complex seismic fields, geology and topography near the site, are required for noise cancellation. In this presentation, we delve into the seismic/Newtonian noise challenges encountered in the ET operation and explore machine-learning approaches to address them. By understanding the sources and characteristics of seismic noise, we aim to devise effective strategies that could significantly enhance ET's detection capabilities. Leveraging the power of artificial intelligence, we explore how machine learning algorithms can enhance our ability to distinguish gravitational wave signals from background noise, even in the presence of seismic disturbances.

Charge-breaking opportunities for the early Universe
Igor Ivanov (Zhongshan U., Zhuhai, China)

The hot early Universe must have evolved through one or several phase transitions around the electroweak epoch, but the details of this evolution are not known. Multi-Higgs models often possess scalar potentials which, at finite temperatures, exhibit several competing minima and may lead to phase transitions of peculiar nature. In this talk, I will show that there exists a regime in the two-Higgs-doublet model in which thermal evolution of the early Universe passes through an intermediate phase with a charge-breaking vacuum. This regime leads to a sequence of phase transitions and can be tested at colliders. In addition, I will show that multi-Higgs-doublet models can support phase transitions in which two neutral minima are separated by a charge-breaking bubble wall, with remarkable and yet unexplored cosmological consequences.

Searching For Transiting Planets around Red Clump Stars: Constraining the Occurrence Rate of Close-In Jovian Planets
Victoria Bonidie (Pittsburgh University)

The fate of close-in planets as their host stars evolve past the main sequence is not well understood. To address this question, we perform a transit survey in the Kepler light curves of red clump (RC) stars, the post-RGB core-helium burning phase for low-mass stars. Our search yields no evidence for transiting Jupiter-sized planets in our sample, allowing us to place the first upper limits on the occurrence rate of exoplanets around RC stars. We find a 1-σ upper limit occurrence range between 0.1%< f<0.7% for Hot Jupiters, with a mean upper limit of 0.3%. This mean becomes 0.5% when considering all Jupiter-sized planets with orbital periods <20 days. In this talk, I will discuss our current understanding of the effects stellar evolution has on planetary survival, the techniques and outcome of my search, and the implications of finding no evidence of Hot Jupiters around RC stars.

Companion-Disc Interactions: From Planet Formation to Gravitational Wave Sources
Josh Calcino (Tsinghua University)

Accretion discs are ubiquitous in astrophysics. Around protostars, they are responsible for the formation of planetary systems and are known as protoplanetary discs. Around supermassive black holes, they produce the brightest electromagnetic phenomena in the Universe, active galactic nuclei (AGN). Spatially resolved observations of protoplanetary discs have revealed a multitude of substructures. From gaps and cavities, to spiral arms and perturbed kinematics, these observations are highly suggestive of companion-disc interactions. Protoplanetary disc kinematics in particular are becoming a valuable method for uncovering hidden companions. While there exists a substantial amount of literature on the understanding of planet-disc interactions and their observational implications, little attention has been made towards circumbinary discs. Using 3D hydrodynamical simulations post-processed with Monte Carlo radiative transfer, I found several kinematic and morphological features that can identify circumbinary discs. I will show that Doppler flips, spiral arms, eccentric gas motion, and vortex-like kinematic signatures are commonly seen. These complex kinematic structures may explain some of the observed, and potentially misinterpreted, kinematic signatures seen in the literature. I will finish the seminar by providing a brief summary of recent promising results that suggest stellar mass binary black holes embedded in AGN discs can be the progenitors to gravitational wave sources.

The First Galaxies in the Universe with JWST
Christopher J. Conselice (University of Manchester)

I will present the recent discovery of a significant number of new candidate high-redshift (z > 6.5) galaxies in the early Universe using the JWST Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) GTO survey, as well as public JWST data. This is currently the largest JWST investigation of its kind to date, with over 100 square arcmins spanning 6 fields to some of the greatest depths reachable thus far. I will present the details of our z>6.5 sample of more than 1000 galaxies, including many new candidates between 12<z<20, increasing by a significant amount the number of galaxies at this epoch. My talk will describe how our reliable sample at the highest redshifts is identified, present their star formation and stellar population properties, as well as the first robust UV luminosity and stellar mass functions at z > 10 based on these galaxies. I will conclude with the implications of our results for the theoretical ideas behind galaxy formation as well as what our results imply about the reionization of the universe.

Toward a comprehensive view on baryonic and dark matter components in massive galaxy clusters with multi-probe mass models
Benjamin Beauchesne (EPFL Switzerland)

Galaxy clusters are the largest structures bound by gravity in the Universe. Such massive objects bend the light from background objects, allowing us to study their mass contents with the gravitational lensing effect. In the context of the standard cosmological model, their contents are largely dominated by dark matter (DM) and are thus a unique laboratory for studying its properties. Gravitational lensing alone can only probe the total mass along the line of sight. To go beyond this limitation we need to combine multiple mass probes within lens mass models to fully disentangle baryonic (i.e. ordinary matter) and dark matter. In such a study, the electromagnetic emission from the baryons is used to recover their intrinsic mass distributions to extract the DM from the total one in a cluster. The baryons are distributed among the galaxies, the intra-cluster gas, and the intra-cluster stars. Ground-based observatories are sufficient to recover the photometry and spectroscopy of cluster galaxies and estimate their masses, while space-based X-ray observatories can uniquely map the gravitationally heated plasma at the core of the cluster. The intra-cluster stars appear as a faint diffuse cluster-scale light emission (i.e. Intra-Cluster light denoted ICL). Current facilities such as the James Webb Space Telescope (JWST) have recently revealed such components in clusters and pushed the frontier of our understanding, challenging current modelling of its formation. I will introduce the study of the galaxy clusters, what they have brought to our understanding of DM, and the current successes and challenges in the field. I will then develop on how to combine multiple mass probes to lensing models to create comprehensive mass models of galaxy clusters. I will give an overview of the different ways to make such models from the current state-of-the-art, present some results that highlight their benefit, compare them to more standard approaches and future prospectives.

From theory to application: Empirical Mode Decomposition in Turbulent Flows
Esther Lagemann (University of Washington)

Turbulent flows are characterized by a complete spectrum of scales. From a spatio-temporal perspective, the interaction of these scales usually involves non-linear and unsteady processes. However, the mathematical and physical limitations of state-of-the-art data analysis tools prohibit an accurate investigation of such dynamics. To close this gap, the 2D noise-assisted multivariate empirical mode decomposition (2D NA-MEMD) is introduced. This data-driven decomposition method extracts physically meaningful modal representations of the flow field based on the scales inherent to the data. The simultaneous decomposition of multiple variates, e.g., spatially resolved velocity components at several time instants, preserves relations between these components in their modal representations such that causal relations can be investigated on a modal basis. For time-resolved data, additional properties like the noise assistance ensure a temporal coherence of the extracted modes in line with their physical dynamics. Consequently, spatially and temporally continuous modal representations of the flow field with an adaptive, scale-based segmentation are obtained that can be used to study non-linear and unsteady dynamics of turbulent flows. In this talk, we will first cover the fundamentals of the EMD and its extensions and subsequently discuss its application to the in-cylinder flow of a combustion engine, the transonic airfoil buffet flow, and in the context of friction drag reduction.

Strong Gravitational Lensing: A Powerful Magnifying Glass for Resolving High-z Star-Forming Galaxies
Carla Cornil-Baïotto (IFA UV, Chile)

Mapping the dust and the molecular gas distribution at sub-kpc scales is crucial for understanding the physical mechanisms that govern the star formation activity in galaxies. Aided by adaptive optics, near-IR IFU observations for galaxies at the so-called cosmic noon, 1 < z < 3, have shown that a large fraction of the star-forming galaxies exhibit turbulent and clumpy rotating disks. These structures have been also revealed by rest-frame ultraviolet observations with the HST. The higher gas fractions at these redshifts allow the formation of such massive complexes, however, conducting spatially-resolved studies of their internal structure becomes extremely challenging at high redshifts, as our best telescopes lack the resolution to resolve the ISM in galaxies. The strong gravitational lensing phenomenon overcomes this limitation by magnifying background sources located behind massive galaxy clusters, providing an excellent opportunity to resolve distant and typically faint galaxies. In this seminar, we present the ALMA study of an exceptionally bright and extended, strongly lensed, z~2.8 galaxy laying behind the Bullet Cluster, which exhibits one of the highest differential magnifications ever recorded at submillimeter wavelengths (up to 40!). This extreme magnification, combined with our new ALMA 0.2”-resolution of its CO(3-2) and continuum emission, allows us to reach an exceptional ~40-100 parsec resolution in a faint galaxy that is representative of the typical galaxy population at these redshifts. This has enabled exquisite spatially resolved diagnostics of the star-forming properties of the galaxy, including its morpho-kinematic properties, the exploration of Larson's relations, the Schmidt Kennicutt law, and other future projects to be presented at the seminar.

How can we investigate moon-magnetosphere interactions with telescope observations?
Stephan Schlegel (Institute of Geophysics and Meteorology, University of Cologne)

The strong magnetic field and dense plasma environment in the inner Jovian magnetosphere allows for intriguing moon-magnetosphere interactions. These interactions have been studied extensively using both in-situ and remote measurements. Telescope observations have mostly been used to infer properties of the immediate vicinity of the observed object, e.g., the atmosphere or the plasma environment. Alternatively, these remote observations can also be used as a diagnostic for characteristics of the inner magnetosphere far from the observed object. Here, this is presented at the case of two different examples. First, we show how the position and morphology of the Io footprint can be used to obtain information about the Io plasma torus and Io's atmosphere. Afterwards, the effects of the plasma sheet and magnetic field environment on the far ultraviolet glow of Europa are discussed.

Exploring the Composition of Neutron Star Matter with Astrophysical Observation
Prasanta Char (Salamanca U. & Virgo)

Astrophysical observations of neutron stars allow us to study the physics of matter at extreme conditions beyond the scope of any terrestrial experiments. In this work, we perform a Bayesian analysis putting together the available knowledge from the nuclear physics experiments, observations of different X-ray sources, and gravitational wave events to constrain the equation of state of supranuclear matter. In particular, we employ a relativistic mean-field model to calculate the saturation properties of nuclear matter i.e. the symmetry energy and its slope parameter, the incompressibility, the effective mass of the nucleon, the binding energy per nucleon, and the saturation density. Then, we investigate if it is possible to reconcile the inferred values of those quantities from observational data with those obtained from nuclear experiments and compute a joint posterior of these quantities incorporating all the available knowledge.

Looking beyond standard neutrino flavour proportions at IceCube
Atri Bhattacharya (AGUST Cracow)

We discuss the capabilities of IceCube to detect individual flavours in incident neutrino fluxes. Following an understanding of the expected flavour proportions from standard neutrino mixing, we consider some beyond standard model scenarios that lead to altered neutrino mixing probabilities and therefore to non-standard proportions of the different flavours in the incident flux, especially as a function of the incident neutrino energies. We briefly discuss how this could potentially lead to detectability of the involved Physics at IceCube and future, larger neutrino telescopes.

Jupiter Auroral Lightshow: Effect of Electron Precipitation on Jupiter's Atmosphere
Bilal Benmahi (LPAP - STAR - ULiège)

Jupiter's powerful auroras are shaped by interactions between its magnetosphere and atmosphere. Using data from NASA's Juno mission, including observations from the Ultraviolet Spectrograph (UVS) and in-situ particle measurements, this presentation focuses on how magnetospheric electrons drive these auroras. By analyzing the ultraviolet emissions of hydrogen (H₂) and comparing them with results from electron transport and hydrogen emission models, we can better understand the characteristics of the electron population responsible for the Jovian auroras. This research contributes to a more comprehensive understanding of the physics and chemistry of Jupiter's upper atmosphere, as well as of other magnetized planets in the Solar System.

Magnetic field topologies of low-mass stars: evolution and effects
Stefano Bellotti (University of Leiden)

Studying the magnetic fields of stars is paramount to understand their effect on internal structure, formation, evolution, and activity. In particular, monitoring secular changes of the field’s configuration in low-mass stars (M< 1.2 MSun) provides key constraints on how fundamental stellar parameters, such as mass and rotation period, impact the internal dynamo processes for the generation and sustain of magnetic fields through stellar lifetimes. This also allows us to contextualise the solar dynamo theory, which is still incomplete and an active field of research. Knowledge about stellar magnetic fields finds interest also from an exoplanet perspective. Indeed, owing to the tight connection with stellar winds and radiation output, stellar magnetic fields regulate the space environment in which exoplanets are embedded. They therefore represent important ingredients to understand planetary atmospheric evolution, star-planet interactions, and habitability. In this talk, I will describe the magnetic field reconstruction by means of Zeeman-Doppler imaging and recent work dedicated to monitor the secular evolution of such magnetic fields in the form of magnetic cycles. I will then outline an observational campaign whose aim is to characterise the magnetic field and environment of known exoplanet hosts in preparation of the Ariel mission.

Probing Exoplanets through High-Contrast and High-Resolution Spectroscopy
Dimitri Mawet (CalTech)

In this seminar, I will present scientific advancements achieved through the synergy of high angular resolution, high contrast, and high-resolution spectroscopy, focusing on results enabled by the Keck Planet Imager and Characterizer (KPIC) at Keck Observatory and a recent groundbreaking discovery from CRIRES+ at the VLT. KPIC’s pioneering single-mode fiber-fed design integrates adaptive optics with infrared high-resolution spectroscopy, facilitating detailed analyses of exoplanets and brown dwarf companions at close separations. In just a few years, this instrument has more than doubled the number of substellar companions with measured metallicities, C/O and isotopologue ratios, and spin rates, and has launched the first dedicated exo-satellite survey. KPIC’s achievements, including the first demonstration of cross-aperture fiber nulling at high spectral resolution, lay a strong foundation for upcoming instruments such as Keck-HISPEC (2026) and TMT-MODHIS (2035+), which promise even more powerful spectroscopic capabilities for large-scale exoplanetary studies. While large ground-based telescopes are critical for these photon-intensive investigations, space remains essential for achieving the extreme contrasts needed to detect and characterize exo-Earths. I will also discuss the current status of NASA’s Habitable Worlds Observatory, a next-generation space telescope designed to search for signs of life on Earth-like exoplanets orbiting Sun-like stars.

Swimming at night: assessing the migration of fin whales in the Mediterranean through a multi-disciplinary approach
Clément Fontana (National Institute of Oceanography and Applied Geophysics - OGS)

The fin whale (Balaenoptera physalus) is one of eleven cetacean species that permanently inhabit the Mediterranean, and it holds the title of the second largest animal on the planet. Setting up conservation efforts for this species in the Mediterranean is crucial, as collisions with ships are a leading cause of non-natural mortality in an area characterized by heavy maritime traffic.

Despite its significance, little is known about the behavior of the Mediterranean subpopulation, which is genetically distinct from its nearest relatives in the North Atlantic. In this seminar, we will examine the tracks of several fin whales in the western Mediterranean that have been monitored over several months using satellite telemetry tags.

We will begin in the Sicily Channel, where two whales collaborate to locate optimal foraging areas, influenced by variations in geostrophic currents due to tidal changes. Next, we will follow one of these whales on its northward migration to the Cap Corse, where a coupled physical-biogeochemical model illustrates the connection between mesoscale eddy dynamics and the whale behavior.

We will also discuss the annual dynamics of phytoplankton in the Gulf of Lion, which experiences a recurrent spring bloom. This gulf is known for its rich biogeochemical activity, attracting fin whales regularly. To monitor their vocalizations, an acoustic monitoring system was established there, allowing us to assess both intra- and inter-annual fluctuations in their presence. Additionally, other fin whales have been tagged in this area, with most remaining in the basin. However, one whale notably migrated to the Tagus estuary, a region significantly affected by nutrient runoff from the land and eutrophication. This whale spent part of the winter there, adjusting its position in the Gulf of Cadiz to adapt to the instabilities caused by the mixing of Mediterranean and Atlantic waters.

Finally, we will explore genetic constraints and lunar influences on the motivations of fin whales to migrate to distant regions to meet conspecifics from around the globe.