July 2025

03/07/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Revealing the Cosmic Build-up of Interstellar Dust with Space Telescopes — The Nearby Universe as a Laboratory
Julia Roman-Duval (Space Telescope Science Institute)

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.

June 2025

26/06/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Fast Radio Bursts
Vicky Kaspi (McGill University)

Abstract

Fast Radio Bursts are a recently discovered phenomenon consisting of
brief (typically few millisecond) bursts of radio waves coming from
far outside our Milky Way galaxy, indeed from cosmological distances.
Their origin is unknown.  I will review what is known about these
mysterious sources, and how they can act as novel probes of the matter
distribution in the Universe.  I will focus on results from the CHIME
Fast Radio Burst Project, which uses a new Canadian digital radio
telescope that is revolutionizing our view of the fast transient sky.
I will also introduce the CHIME/FRB Outriggers, which will enable
precise sky localizations for >1000 CHIME FRBs, hence permit host
galaxy ID and redshift determinations.

May 2025

22/05/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — What do meteorites teach us about planet formation?
Joanna Drążkowska (MPG)

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.

15/05/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — More Accurate Together: Opportunities in Multi-Survey Cosmology
Prof. Elisabeth Krause (Uni Arizona)
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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.

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08/05/25 (Thursday)
15:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Theoretical Insights into Tidal Disruption Events: Rates, Accretion, Emission, and Feedback
Jane Lixin Dai (University of Hong Kong)
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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.

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April 2025

10/04/25 (Thursday)
15:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Studying the best exoplanets in our front-yard: Gas giant exoplanets and their climates
Christiane Helling (Director of the Space Research Institute (IWF) of the Austrian Academy of Sciences)
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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.

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03/04/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Low column-densities in nearby galaxies: probing faint neutral hydrogen with MeerKAT.
Erwin de Blok (ASTRON Science)
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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.

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March 2025

27/03/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Neutrinos in the Era of Multi-Messenger Astronomy
Irene Tamborra (Niels Bohr Institute)

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.

20/03/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The effect of high-energy particles on exoplanetary atmospheres
Donna Rodgers-Lee (Dublin Institute for Advanced Studies)
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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.

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13/03/25 (Thursday)
15:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Exploring New Frontiers in Planetary Astronomy: From Magma Oceans to Liquid-Water Worlds
Renyu Hu (NASA)
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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.

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February 2025

27/02/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The FLAMINGO simulations of large-scale structure and galaxy clusters
Joop Schaye (Leiden University)
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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.

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20/02/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Quantum Computing and its potential for astrophysics and astronomy applications
Luigi Iapichino (Leibniz Supercomputing Centre)
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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.

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13/02/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Rings of Dust and Gas - The Keys to Understanding the Origins of Planets
Til Birnstiel (LMU Munich)
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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.

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06/02/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Life on the edge: reconnection-powered emission at the boundaries of black hole jets
Lorenzo Sironi (Columbia University)
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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.

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January 2025

30/01/25 (Thursday)
15:15, Auditorium Telescopium (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Cosmic Chemistry of Complex Aromatic Molecules
Sandra Bruenken (Radboud University)

Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are, together with fullerenes, the largest molecular species that have been detected in space. They are a dominant reservoir for cosmic carbon and are important drivers – and probes – of the physical and chemical evolution of astrophysical environments, for example through photoelectric heating and their crucial role in interstellar chemistry. Recent observations of their infrared emission bands with JWST provide unprecedented detail of their spatial distribution, and radioastronomical observations in the past years confirmed their presence also in the cold interstellar medium. However, many questions related to PAHs remain open, such as the exact composition of the astronomical PAH family, their fragmentation pathways upon energetic processing (top-down processes), and their formation pathways from smaller molecular units (bottom-up processes).
 
In this talk I will outline how laboratory kinetic and spectroscopic studies under conditions mimicking those in space can help to answer these questions. I will highlight how we use infrared action spectroscopy to structurally characterize, e.g., PAH fragments that lost acetylene or hydrogen, and how we often find surprising isomerization behaviour leading to thus far not considered classes of astronomical PAHs. Furthermore, we study the kinetics of PAH formation processes via in-situ spectroscopic probing of ion-molecule reactions at low temperatures. Almost as a side product, these different studies provide infrared reference data on a large class of ionic PAHs that are crucial for comparison with astronomical observations.
23/01/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — The Dynamics of Planet Formation
Myriam Benisty (Director at the Max Planck Institute for Astronomy (MPIA))

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.

16/01/25 (Thursday)
15:15, Auditorium Eridanus (ESO HQE, Garching) | ESO Garching
Munich Joint Astronomy Colloquium
Talk — Dwarf galaxies as probes for cosmological models
Laura Sales (University of California)
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Abstract

Dwarf galaxies pose strong constraints to the Lambda Cold Dark Matter
(LCDM) model, with several outstanding challenges still to be reconciled
between theoretical models and observations. I will review how dwarf
galaxies can help us reconstruct the predicted hierarchical assembly of
large systems like groups and clusters through the intra-cluster light
component. I will also focus on some of the tensions between theory and
observations, including the sizes of dwarf galaxies, the presence of dark
matter cores and the diversity of rotation curves. I will highlight the
important role of modeling the physics of baryons in galaxy formation
simulations to compare observations to cosmological predictions. From such
comparison, a few observational milestones arise as promising probes of the
LCDM model: a census of the extended regions around groups and clusters in
search of low-surface brightness features, phase-space studies of stars in
nearby cored dwarfs, and measurements of the degree of burstiness in the
star formation of low mass galaxies.

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