December 2025
Abstract
Core-collapse supernova remnants (SNRs) offer a powerful diagnostic of massive-star evolution and explosion physics. Their complex morphologies and chemical inhomogeneities retain signatures of the supernova (SN) engine, including asymmetries, nucleosynthetic yields, and compact-object formation. In young remnants (<5000 years), the debris still preserves this early "memory", while the large-scale structure reflects interactions with the circumstellar medium (CSM) shaped by the progenitor's mass loss and, potentially, binary evolution. Studying SNRs is therefore essential not only for understanding SN physics and the mechanisms that trigger explosion, but also for probing the final fate of massive stars and the poorly understood processes governing late-stage mass loss.
In this talk, I will review recent advances in modeling young to middle-aged core-collapse SNRs, drawing on observationally motivated simulations of neutrino-driven explosions that follow the evolution from core collapse to ages of thousands of years. I will focus on well-studied remnants such as Cassiopeia A (where JWST has revealed unprecedented details) as well as SN 1987A and its emerging compact remnant, and extragalactic cases like SN 2014C that highlight the diversity of CSM environments and progenitor pathways. I will also briefly discuss additional remnants, including IC 443 and others, that provide complementary perspectives on shock physics, particle acceleration, and stellar feedback.
Finally, I will outline the growing potential of current and future observational facilities (e.g., JWST, newAthena, HUBS, and the Line Emission Mapper), which will enable detailed mapping of ejecta composition, temperature, and dynamics across many remnants, strengthening links between simulations and observations and advancing our understanding of how massive stars end their lives.
Video
Abstract
Polycyclic Aromatic Hydrocarbons (PAHs) are thought to sequester a large fraction (10-25%) of all carbon in the Universe. While strong circumstantial evidence for their presence in space has existed since the 1980s, it is only in the last few years that the first individual PAH species have been definitively detected. In this talk, I'll describe the synthetic and spectroscopic laboratory work, computational approaches, and observational efforts which have led to these discoveries, discuss our current understanding of the formation and molecular evolution of PAHs in space, and describe the growing body of evidence that these species, in no small part, influence the inventory of raw organic material delivered to early planets. I'll conclude by taking a critical look at open questions related to PAH chemistry in space and the prospects for the field going forward.
Video
November 2025
Abstract
Our dynamic Universe is adorned by cosmic fireworks: energetic and ephemeral beacons of light that are a million (nova) to a billion (supernova) times brighter than our sun. Fireworks synthesize most elements in our periodic table -- while supernovae synthesize the lighter elements, neutron star mergers synthesize half the elements in the periodic table heavier than iron. Combining information from multiple messengers - photons, gravitational waves and/or neutrinos - powerfully completes the astrophysical picture. I will describe how we discover cosmic fireworks with robotic telescopes at Palomar Observatory (Zwicky Transient Facility) and how we undertake a global, panchromatic follow-up campaign to characterize the underlying astrophysics (GROWTH Collaboration). Owing to the atomic physics of bound-bound opacity, the infrared is the most sensitive probe of the heaviest elements. I will describe building a series of surveyors to open up wide-field infrared astronomy: Palomar Gattini IR, WINTER, and now the Cryoscope pathfinder in the Antarctic.
Video
Abstract
The chemical composition of planets is largely inherited from that of their natal protoplanetary disks. In recent years, the characterization of disk chemistry has advanced significantly. (Sub-)millimeter interferometers such as ALMA have enabled the detection of emission lines from a wide range of molecular species—including deuterated and organic molecules—and revealed their radial and vertical distributions within disks. Meanwhile, JWST has begun to uncover the composition of disk ices.
In this seminar, I will review the chemical evolution of planet-forming disks from the earliest protostellar stages to the emergence of planetary systems, highlighting how accretion and ejection processes, as well as environmental effects, shape their chemistry. I will focus in particular on complex organic and deuterated molecules, which serve as key tracers for reconstructing our chemical heritage through comparisons with the pristine bodies of the Solar System.
Finally, I will discuss how the upcoming SKA Observatory (SKAO) will open new observational frontiers in this field by enabling the detection of emission lines from heavier molecules in planet-forming regions.
Video
Abstract
Exoplanets form across a wide range of distances from their host stars, from close-in orbits around the central star to the outer protoplanetary disks. These environments differ dramatically in physical conditions. In the inner disk, we use 3D magnetohydrodynamical simulations to study magnetospheric accretion and planetary migration in this highly turbulent region. We find that Earth-mass planets migrate very slowly, often stalling near the dead-zone inner boundary, while giant planets may halt near the magnetospheric truncation radius. In the outer disk, beyond tens of au, stellar irradiation — especially when modulated by shadows from the inner disk or accretion columns — can drive a variety of disk structures. Using 3D radiation-hydrodynamical simulations, we show that these shadows act as an asymmetric driving force, leading to spirals and rings. They can influence planet formation, and their unique velocity features are potentially observable with ALMA molecular line observations.
Video
Abstract
Two of the biggest questions in astronomy are "how did we get here?" and "are we alone?" These questions relate in part to the composition of planets, which is largely determined by the composition of the solids in planetary nurseries within protoplanetary disks. These solids begin as ice-mantled dust grains that grow in dense molecular clouds prior to the collapse of protostars. Astrochemical comparison of gaseous isotope ratios in clouds, protostars, and comets suggests that some cold, interstellar ices are directly "inherited" from the molecular cloud by some Solar System bodies. However, icy grains may be thermally processed during the formation of the first protostar and disk in the first 100,000 years, due to the intrinsic temperature gradient close to the protostar and to variable accretion outbursts that heat the infalling solids. Thermal processing should lead to various degrees of fiery "reset" through sublimation and re-condensation of the disk ice and even silicates. There is evidence for reset in the meteoritic record, with the oldest re-condensed minerals marking the t=0 moment of the Solar System planet formation timeline. Discovering which ice and dust species survive is critical to understanding when and where planets can form in these disks, along with the possibility of them becoming habitable.
The James Webb Space Telescope is uniquely suited to answer this question, as it is capable of sensitively detecting all major and many minor ice and silicate species in the near- and mid-infrared. I will synthesize results from several JWST programs, including the ERS program Ice Age (http://jwst-iceage.org/), revealing how solid state chemistry evolves from the dark regions of molecular clouds to planet-forming regions of disks. We see early chemical pathways to mixed complex ices and CO2 in the cloud, and icy grains in the cloud have also grown, which may promote grain survival. However, JWST has also seen evidence for total thermal destruction of even silicates towards some protostars. These data identify for the first time an example of total sublimation of rocky dust grains and subsequent re-condensation, which marks the t=0 moment of planet formation according to meteoriticists. This validates the view from the meteoritics community that reset regulates the composition within the rocky-planet-forming regions of 100,000 year old disks. By 2-3 million years old, in the outer regions of mature disks, the situation appears to have reversed. There the distribution and absorption band profile of CO ice in protoplanetary disks suggests that it has become trapped in the CO2 ice matrix on the dust grains, indicating that inheritance becomes important at certain times and disk radii. I end by discussing which future observations and models are needed to understand how the interplay of reset and inheritance over time impacts the evolution of planetary compositions as they form and evolve.
Video
October 2025
Abstract
Dust affects almost all astronomical observations, including as a signal that encodes the chemical history of the interstellar medium and as an obscuring foreground that must be mitigated. In this talk, I will address two aspects of the dust lifecycle that have bearing on both dust as a signal of interest and as a cosmological foreground. First, I will present new evidence for the rapid growth of polycyclic aromatic hydrocarbons (PAHs) in translucent gas. This process may help explain how high-redshift galaxies (up to z~7) observed by JWST can have such high PAH abundance. Further, changes in PAH abundance have a direct impact on interstellar reddening and may be a limiting systematic of classic reddening maps based on far-infrared dust emission. In the second part of my talk, I will present evidence based on polarized far-infrared emission for the homogenization of dust in the interstellar medium. I will highlight consequences for modeling dust in cosmic microwave background polarization experiments searching for primordial B-modes. Finally, I will present the far-infrared Probe mission concept PRIMA, and in particular how its ability to measure PAH emission across cosmic time and dust polarization in the Local Universe will enable major leaps in addressing these questions.
Video
Abstract
The Milky Way is still evolving. The accretion of gas and stars from our surroundings in the Local Group continues to shape and build the Galaxy. Multi-phase gas flows play essential roles in cycling baryons and metals through the Galactic ecosystem and fueling the Galactic gas supply. In this colloquium I will review recent work on the gas flows around the Milky Way, based on UV/optical absorption-line observations from HST and VLT, H I 21 cm observations, and hydrodynamic simulations. After introducing the use of high-velocity clouds (HVCs) as tracers of Galactic inflow and outflow, I will discuss the Galaxy’s cool nuclear outflow and the giant Fermi and eROSITA Bubbles found on either side of the Galactic Center. I will then discuss the gas content of the Magellanic System, which is interacting with the Milky Way and slowly transferring large amounts of gas to the Galaxy. This will include new results on the LMC’s gaseous halo and the distance to the Magellanic Stream.
Video
Abstract
In the past decade, Astrochemistry has witnessed an impressive increase in the number of detections of new molecular species in space. The majority of these detections are related to complex organic molecules (or COMs), defined as carbon-based compounds with more than five atoms in their molecular structure. Interestingly, some of these complex organics are of prebiotic interest, and hence, they are believed to be involved in the first biochemical processes that led to life. Recently, we have obtained ultra-sensitive, broadband spectral surveys toward the G+0.693 molecular cloud located in the Galactic Center, and known to be one of the richest chemical repositories of the Milky Way. Our spectral surveys carried out with the IRAM 30m, Yebes 40m, and APEX telescopes have allowed us to detect more than 25 new molecular species, which include precursors of ribonucleotides, amino acids, sugars, proto-proteins, and proto-lipids, as proposed in theories of the origin of life. In this talk, I will present all these findings and I will analyze how chemical complexity builds up in the interstellar medium, not only in the extreme environment of the Galactic Center but also during the initial conditions of Solar-system formation.
Video
September 2025
Abstract
Ultra-faint dwarfs are the lowest mass and most dark-matter dominated systems known. The shallow potential wells make them susceptible to feedback from star formation and their low baryonic content allows us to use their stars as test-particles in the dark matter potential. The main challenge is that most stars in such dwarfs are typically very faint. Here I will give an overview of the MUSE-Faint survey, a MUSE GTO survey of 10 ultra-faint dwarfs. After introducing the survey, I will outline how the high density of stellar spectra obtainable with MUSE can be used to constrain the dark matter content and density profiles of the galaxies, while the repeated observations can be used to place constraints on the binary star content in these reionization relics. I will also discuss briefly the stellar content and the luminosity-metallicity relation at the edge of galaxy formation.
Video
Abstract
Astronomical transients are signposts of catastrophic events in space, including the most extreme stellar deaths, stellar tidal disruptions
by supermassive black holes, and mergers of compact objects. Thanks to new and improved observational facilities we can now sample
the night sky with unprecedented temporal cadence and sensitivity across the electromagnetic spectrum and beyond. This effort has led
to the discovery of new types of astronomical transients, revolutionized our understanding of phenomena that we thought we already knew,
and enabled the first insights into the physics of neutron star mergers with gravitational waves and light. In this talk I will review some very
recent developments that resulted from our capability to acquire a truly panchromatic view of transient astrophysical phenomena. I will
focus on two key areas of ignorance in the field: (i) What are the progenitors of stellar explosions and what happens in the last centuries
before death? (ii) What is the nature of the compact objects produced by these explosions and what happens when compact objects merge?
The unique combination of Discovery Power (guaranteed by planned transient surveys like LSST, combined with efforts in the realm of artificial
intelligence) and Understanding (enabled by multi-messenger observations) is what positions time-domain astrophysics for major advances in
the near future.
July 2025
Abstract
Compact object binaries are a class of binary systems with periods below a few hours and physical separations
between components as small as the Earth-Moon distance consisting of compact objects such as white dwarfs,
compact helium stars and in rare cases even neutron stars. The study of these short period systems and their
subsequent mergers are important to our understanding of a wide range of areas including supernova Ia progenitors,
binary evolution and they are predicted to be the strongest Galactic gravitational wave sources in the LISA band. Compact binaries
are believed to form in interacting binaries through various phases of mass-transfer, which requires poorly understood
physical processes. As such the evolution of these systems is still uncertain. In this talk I will show how the development
of large-scale sky surveys, such as Gaia, the Zwicky Transient Facility, BlackGEM as well as SDSS-V help us to shape our
understanding of the final stages of compact binary evolution. I will also present a few highlights, including the discovery of
a candidate supernova Ia progenitor, and a new class of mass transferring compact helium stars.
Abstract
Measuring the Hubble constant is difficult. In the local universe, the H0 determination is hampered by two impediments: the local disturbance of the expansion field and the rarity of luminous distance indicators with a reliable calibration. This led to the principle of the distance ladder, where distance indicators are calibrated at lower distances and then applied as calibrators of another distance indicator at larger distances. Several methods have been used in the past years to measure the local expansion rate, but they have not converged. In addition, some of the local H0 determinations disagree with the derived expansion rate from the Lambda CDM model as calibrated by the cosmic microwave background resulting in the ‘Hubble tension’. Recently, a Garching team has improved the Expanding Photosphere Method (EPM) for type II supernovae to derive H0 bypassing the distance ladder. This promises to become an independent and unique probe of the cosmic expansion rate.
Video
Abstract
The first generation of stars, often called Population III (or Pop III), form from metal-free primordial gas at
redshifts z ~ 30 and below. They dominate the cosmic star formation history until z ~ 20-15, at which point
the formation of metal-enriched Pop II stars takes over. I review current theoretical models for the formation,
properties and impact of Pop III stars, and discuss observational constraints. I argue that primordial gas is highly
susceptible to fragmentation and Pop III stars form as members of small clusters with a logarithmically flat mass
function. Feedback from massive Pop III stars plays a central role in regulating subsequent star formation, but major
uncertainties remain regarding its immediate impact. Direct observations of Pop III stars in the early Universe remain
extremely challenging, whereas stellar archeological surveys allow us to constrain both the low-mass and the high-mass
ends of the Pop III mass distribution. Observations suggest that most massive Pop III stars end their lives as core-collapse
supernovae rather than as pair-instability supernovae. I also speculate about the formation of supermassive stars, which
under very specific circumstances can get as massive as several 100.000 solar masses and can become the seeds of the
supermassive black holes observed in the high-redshift universe.
Video
Abstract
Variations in the abundance of interstellar dust have important implications for our ability to trace the chemical enrichment of the universe, stellar mass assembly, and profoundly affect galaxy evolution. I will present results from three observational efforts to characterize the variations of the dust content and properties within and between galaxies, in particular as a function of metallicity and gas density. The dust and gas contents of nearby galaxies were measured using far-infrared, HI 21 cm, and CO emission on the one hand, and UV absorption spectroscopy with Hubble on the other hand. Both approaches demonstrate a significant increase of the dust abundance with gas density, even in very low metallicity systems such as Sextans A (7% solar metallicity). Furthermore, the fraction of metals locked in dust decreases with decreasing metallicity, by a factor of 2 from the Milky Way to the SMC, and a factor 4 from the Milky Way to Sextans A. This results in the dust-to-gas ratio (D/G) decreasing faster than metallicity, consistent with chemical evolution models and with measurements in Damped Lyman-alpha systems at redshift <4. However, this decrease in D/G is not as dramatic as suggested from previous FIR measurements in nearby galaxies. Furthermore, ongoing efforts to measure the properties and abundance of the smallest dust grains, polycyclic aromatic hydrocarbons (PAHs), in very low metallicity systems with JWST are revealing that PAHs do exist in those environments, but were previously missed owing to the very small size (pc-scale) of the dense regions in which they can form and survive.
Video
June 2025
Abstract
Video
May 2025
Abstract
Planet formation remains one of the key unsolved challenges in modern astrophysics. Recent exoplanet discoveries and high-resolution observations of protoplanetary disks are reshaping our understanding, prompting a re-evaluation of classical planet formation theories. The omnipresent disk sub-structures helped us to solve the most significant challenges and are driving a new generation of planet formation models. At the same time, increasingly precise laboratory measurements of the Solar System materials provide invaluable benchmarks for the models, giving insights into timescales of planet formation and the large-scale mixing processes. In this talk, I will discuss the understanding of the Solar System formation, which is currently emerging from the synergy of numerical models and meteorite studies.
Abstract
Over the next decade, large galaxy surveys will map billions of galaxies and probe cosmic structure formation with high statistical precision. This talk will outline opportunities and challenges of cosmological analyses in the presence of complex systematic effects using recent results from the Dark Energy Survey as pathfinder examples. In particular, I will describe different cosmological probes measured from photometric data and summarize the recent progress on combining galaxy clustering, weak lensing, cluster clustering and cluster abundances, as well as constraints on astrophysics from small scales. I will conclude with an outlook on cosmology analysis plans and opportunities for future, much larger experiments such as Rubin Observatory’s LSST, Roman Space Telescope and overlapping Cosmic Microwave Background surveys.
Video
Abstract
Tidal disruption events (TDEs) are among the most fascinating astronomical phenomena, offering a unique probe into the properties of massive black holes and the nuclear environments of galaxies. In this talk, I will present results from theoretical calculations of the realistic rates of TDEs for both supermassive and intermediate-mass black holes. These results reveal how TDE rates depend on black hole mass, stellar dynamics, and galactic environments. I will also show state-of-the-art simulations of TDE accretion, outflows and emissions, demonstrating how these processes produce the diverse emission features we observe, including Bowen fluorescence lines. Finally, I will discuss the broader implications of TDEs for black hole growth, particularly in the early universe, and their role in shaping galactic evolution. By exploring these results, we can better understand the physics of TDEs and their critical role in the growth of black holes and the evolution of galaxies across cosmic time.
Video
April 2025
Abstract
More than 7500 extrasolar planets are known, most of them are located within our solar neighborhood where they orbit stars different than our Sun. How does the climate differ on extrasolar planets that orbit such different host stars? By building and utilized virtual laboratories temperature, wind and cloud maps of such extrasolar planets can be predicted and studied. Our virtual laboratories are therefore vital tool to interpret observations from, e.g. space missions like CHEOPS and JWST, and to make predictions for future missions like PLATO and NewAthena. For this, our present focus is on giant gas planets since they have observable atmospheres, and hence, enable us to link modeling and observation to understand their physics and chemistry.
Clouds most often block the view into the atmospheres and hence, hinder the spectroscopic in-depth characterization of the many known exoplanets. Of particular interest is therefore the understanding and the modeling of cloud formation which forms a tight feedback-loop with the local temperature but also the local gas phase composition. The local gas phase is further affected by the external high-energy radiation, including stellar energetic particles and cosmic rays. I will demonstrate why gas giant exoplanets are exciting objects that allow to study cold, cloud forming and hot, ionizing thermodynamic regimes in one and the same objects.
Video
Abstract
The MHONGOOSE Large Survey Project is obtaining ultra-deep 21-cm neutral hydrogen (HI) observations with the MeerKAT radio telescope to map the distribution and kinematics of the low column-density gas in and around 30 nearby star-forming spiral and dwarf galaxies. These deepest resolved HI observations of nearby galaxies to date serve to put additional constraints on the role of accretion of cold gas in the replenishing of these galaxies' gas reservoirs. Observations for the survey have just completed and MHONGOOSE is routinely reaching its target HI column density sensitivity of a few times 10^17 atoms cm^-2, two orders of magnitude lower than the typical values found in galaxy HI disks. Our full-depth data show that the outskirts of our galaxies are complex and dynamic environments, with many potential accretion and interaction features visible in HI that only now become visible due to the excellent column density sensitivity. We detect a significant number of uncatalogued low-mass dwarf galaxies, which enable "Local Group science" in environments at tens of Mpc distance. A first comparison of the MHONGOOSE observations with simulated HI maps from recent cosmological simulations show a marked difference in kinematics and morphology, indicating that cold gas accretion is likely happening in a more gentle way. The sensitive MHONGOOSE observations point the way to a better understanding of the role of gas accretion in galaxy evolution in the nearby universe and identifies opportunities for new HI surveys with the upcoming SKA-MID telescope.
Video
March 2025
Abstract
Neutrinos are fascinating particles heralding the dawn of multi-messenger astronomy. Neutrinos affect the stellar dynamics, drive the formation of new elements, and carry signatures of the yet mysterious physics governing the most energetic transients in our universe. Recent developments on the role of neutrinos in cosmic sources will be reviewed together with the most exciting multi-messenger detection prospects.
Abstract
Galactic cosmic rays and stellar energetic particles are relativistic particles that reach exoplanets. Depending on their energy, they can penetrate exoplanetary atmospheres, similar to what occurs on Earth. The main properties, relevant for these energetic particles, that vary for exoplanetary systems in comparison to the solar system are the stellar winds properties, the exoplanet atmosphere composition and the stellar energetic particle spectrum. The properties of stellar energetic particles for stars other than the Sun remain elusive.
For exoplanetary atmospheres, one of the most important effects due to Galactic cosmic rays and stellar energetic particles is that they ionise the atmosphere. This ionisation leads to exotic chemistry depending on the atmospheric composition. Energetic particles can also drive the formation of prebiotic molecules, the building blocks of life in exoplanet atmospheres. These effects are also relevant for the early Earth atmosphere.
I will discuss our simulation results which show the ionising impact of energetic particles in exoplanetary atmospheres and the early Earth atmosphere. I will show how the stellar wind can affect the energetic particle flux reaching an exoplanet. Finally, I will discuss how JWST could detect the signature of energetic particle-induced chemistry in an exoplanet atmosphere. Such a detection could be used to constrain the energetic particle flux impacting on the exoplanet atmosphere.
Video
Abstract
The discovery of over 5,000 exoplanets has revolutionized our ability to address fundamental questions about planetary habitability and evolution: Are there Earth-like worlds in the Universe? Can they support life? My research accelerates the discovery and characterization of habitable planets by combining cutting-edge observations with advanced models to characterize the atmospheres and surfaces of rocky and low-temperature exoplanets, trace their evolutionary pathways, and search for signs of liquid-water oceans.
In this talk, I will discuss recent breakthroughs in the study of rocky exoplanets, including the first detection of a magma-ocean atmosphere on 55 Cancri e and the discovery of a volcanic, SO₂-rich atmosphere on L 98-59 b using JWST. These findings provide unprecedented insights into the interplay between geological processes and atmospheric evolution, establishing the emerging field of exoplanet geology. I will also present ongoing efforts to identify liquid-water conditions on temperate sub-Neptunes, illustrating how innovative models, such as our next-generation planetary atmosphere framework, EPACRIS, enable us to predict key atmospheric signatures and interpret groundbreaking JWST observations.
Finally, I will discuss the path forward for characterizing Earth-like planets and highlight how today’s exoplanet studies drive scientific and technological priorities of future exploration.
Video
February 2025
Abstract
Observational surveys of the distribution of matter in the universe are becoming ever more precise and continue to be extended to smaller scales. This necessitates accounting for the fact that baryons do not precisely trace the dark matter. The redistribution of baryons by galactic winds, which is the major bottleneck in our understanding of galaxy evolution, therefore requires a convergence between models of large-scale structure and cosmology. I will present results from the FLAMINGO suite of large-volume cosmological, hydrodynamical simulations. The fiducial simulations have been calibrated using machine learning to reproduce the low-z galaxy mass function and cluster gas fractions, but the suite also includes systematic variations in the galaxy formation model and cosmology. The simulations provide insight into the importance of baryonic effects for cosmology using large-scale structure and galaxy clusters.
Video
Abstract
Quantum Computing (QC) is a paradigm with disruptive potential in many areas of computational sciences and large projected impact in research, industry and society. In my talk I will provide a general overview of the main concepts of QC and how it can be integrated into the High-Performance Computing ecosystem as a suitable tool for astronomy and astrophysics. Although application areas in these disciplines are in the first stages of exploration, a few promising directions will be highlighted. Finally, the access paths to QC systems for the local research community will be described.
Video
Abstract
Over the past 15 years, the Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean desert has revolutionized our understanding of planetary formation. ALMA has not only provided the expected large samples and high-resolution images of planet-forming material, but it has also led to groundbreaking discoveries that challenge existing theories. One of the most striking revelations is that planets form much faster than previously thought. In this talk, I will explore the key concepts and scales involved in the process of building planets from micrometer sized cosmic dust. I will discuss how theory and observations help us reimagine how planetary systems, both similar and very different from our own, are formed.
Video
Abstract
The boundaries of relativistic black hole jets—at the interface between the jet and the disk wind—lie at the core of our recent understanding of jet-powered phenomena. They harbor intense velocity and magnetic shears, which provide the free energy needed to power a number of observational signatures. We demonstrate that magnetic reconnection—a process by which opposite field lines annihilate, releasing their energy to the plasma—ultimately governs dissipation of the available free energy at jet boundaries. Reconnection resulting from the nonlinear evolution of Kelvin-Helmholtz type vortices can naturally explain the limb-brightened radio emission of AGN jets, such as M87. Also, inverse Compton scattering within the chain of magnetic islands / flux ropes self-consistently created by reconnection at the jet boundaries can power the mysterious hard X-ray “coronal” emission of X-ray binaries. We will also argue that reconnection-driven hadronic acceleration in the coronal regions of NGC 1068 may be the source of the TeV neutrinos recently detected by IceCube.
Video
January 2025
Abstract
Abstract
Observing campaigns have revealed a great diversity in exoplanetary systems whose origin is yet to be understood. How and when planets form, and how they evolve and interact with their birth environment, the protoplanetary disks, are major open questions. Protoplanetary disks evolve while planets are forming, implying a direct feedback between the processes of planet formation and disk evolution. These mechanisms leave clear imprints on the disk structure that can be directly observed. In this talk, I will review recent observational results on protoplanetary disks, in particular those from the exoALMA Large Program, the first sub-millimeter planet hunting campaign. With exquisite molecular line observations, the velocity structure of fifteen protoplanetary disks revealed a variety of kinematic perturbations possibly due to embedded protoplanets, (magneto-)hydrodynamical instabilities or winds.
Abstract
Video
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