Seminars and Colloquia at ESO Garching and on the campus

Despite their tiny size relative to spiral and elliptical galaxies, dwarf galaxies wield a disproportionately significant cosmological impact holding fundamental information crucial to our understanding of galaxy formation and evolution. Due of their low mass, and their elevated star formation rate, abundant gas, and low metallicity, star forming dwarf galaxies emerge as pertinent counterparts observable in the local Universe, mirroring certain characteristics of galaxies that originated in the early Universe. Due to their proximity and diverse range of gas, dust and stellar content, local universe dwarf galaxies can be thought of as individual snapshots capturing galaxies of varying ages and evolutionary stages which, when studied together can help to construct comprehensive self-consistent models elucidating the evolving properties of the interstellar medium.

In this seminar I will review what we know to date of the properties of the dust and gas in the local universe dwarf galaxies. I will highlight one of the most persistent mysteries prominently noted in dwarf galaxies: the enigmatic nature of the pervasive “dark gas” and discuss how to reconcile the rigorous star formation activity in dwarf galaxies and their scarcity of CO emission, our usual proxy for molecular gas necessary for star formation. The conversion of observed CO to total molecular hydrogen mass in low-metallicity dwarf galaxies is a formidable obstacle complicating our understanding and simulations of molecular clouds to star formation in early-universe galaxies for which our local dwarf galaxies may be useful references.

Unraveling the drivers of the observed diversity of exoplanetary systems has become one of the fundamental issues in modern astronomy, and is vital to understanding our own origins. To this end, correlations between observed exoplanet properties and stellar properties, such as metallicity and age, are important constraints on the theory of planet formation. However, a property that is unobserved for the vast majority of the known exoplanet population is emerging as an important influence on the planet formation process. This property is the star formation environment that is external to the (proto-)planetary system. In this talk I will review evidence that neighbouring stars sculpt planetary systems via stellar encounters, external photoevaporation and late-stage infall. I will also explore how these processes relate to diverse astrophysical problems, from sub-stellar objects to globular clusters. While evidence increasingly suggests that planet formation models cannot be decoupled from the physics of star formation in giant molecular clouds, the precise nature of the link between birth environment and the final planet population remains an exciting mystery.

One of the most powerful tests of our cosmological model is to verify the predicted growth of large-scale structure with time. Intriguingly, many recent measurements have reported small discrepancies in such tests of structure growth ("the S8 tension"), which could hint at systematic errors or even new physics. Motivated by this puzzling situation, I will present new determinations of cosmic structure growth using CMB gravitational lensing measurements from the Atacama Cosmology Telescope (ACT). These ACT DR6 CMB lensing measurements allow us to directly map the dark matter distribution in projection out to high redshifts; new cross-correlations of CMB lensing with unWISE galaxies also allow us to probe the matter tomographically. I will discuss the implications of our lensing results for the validity of our standard cosmological model as well as for key cosmological parameters such as the neutrino mass and Hubble constant.

The stellar initial mass function (IMF) is central to our theoretical and observational understanding of the Universe. For decades, the IMF has been considered to be universal and our explanation for many astrophysical processes heavily relies on this assumption. However, the widely-adopted universality of the IMF is now directly challenged by detailed observations of massive early-type galaxies, where the IMF seems to systematically depart from the Milky Way standard. In this talk, I will showcase how the use of MUSE IFU data allows for an unprecedented view of the stellar population properties of nearby galaxies, and in particular of IMF variations. I will also demonstrate that the combination of detailed stellar population analysis and Schwarzschild dynamical models provides valuable information about the origin of the observed IMF variations in massive galaxies. Finally, I will describe our most recent efforts to go beyond what is currently possible with standard stellar population analyses and the promising prospects for the upcoming years.

Our Cosmic Home, which is the local volume of the Universe centered on us, contains very prominently visible structures, extending over hundreds of Mpc. Such structures, ranging from the Local Group over the Local Void and the most prominent galaxy clusters like Virgo, Perseus, Coma and many more, represent a formidable site where extremely detailed observations exist. Therefore there is a long standing effort to determine the properties of the local, large scale structure. This effort is accompanied by constructing cosmological simulations which describe the formation of these specific structures. Thereby, cosmological simulations of the formation of galaxies and galaxy clusters within the Local Universe, rather than any other, randomly selected part of the cosmic web, can be an important tool to test our formation and evolution theories of galaxies and galaxy clusters in detail. I will present results from our latest realization of such simulations to answer some key questions: How good are such simulations representing the local, large scale structure? How well can we reproduce the properties of individual galaxy clusters and their formation history? Can we start testing baryonic physics by comparing such simulations to observations?

Our current understanding of galaxy formation is based on the presence of an elusive matter component: the Cold Dark Matter (CDM). This simple model has ben challenged many times in the past decade, mainly by galaxy observations on small scales: from the abundance of satellites, to the distribution of dark matter within galaxies, and more recently by the discovery of galaxies "without" dark matter.

In my talk I will first revise all these claims with the help of cosmological numerical simulations of galaxy formation from the NIHAO project. I will then discuss whether there is indeed an observational motivated need to abandon Cold Dark Matter and move beyond such a simple model.

Exoplanet research has revolutionized our understanding of planetary systems beyond our own solar system. In particular, characterizing the atmospheres of exoplanets is crucial for determining the nature of their environment and tracing their formation history. In this talk, I will explore the latest exoplanet atmospheric characterization with Hubble and JWST from the UV to the mid-IR across a wide population of exoplanets. I will discuss the challenges in analysing the observations from systematics to chance events. I will also highlight the ways we interpret the spectra to understand the chemistry and dynamics of the atmosphere. I will finish with some of the most recent discoveries and future prospects for exoplanet atmospheric characterization.

What is the origin of magnetism on large cosmic scales? How are cosmic rays accelerated and how do they move through the cosmos? What are their effects on structures such as galaxies? These are the questions we explore in this talk.

Recent advances in radio observations have shed new light on the cosmic ray and magnetic field distributions in the Universe, from the circumgalactic medium all the way to cluster of galaxies and cosmic voids. Cosmic rays play a crucial role in driving galactic winds, which, in turn, play a key role in galaxy evolution and the evolution of baryons. Radio observations are also an extinction-free tracer of star formation and provides unique insights into the transport mechanism of cosmic rays.

Using polarisation observations of LOFAR and MeerKAT, we have been able to extract the very first profiles of magnetic fields around nearby and distant star-burst galaxies.

Radio observations have also revealed magnetic fields in cosmic filaments of galaxies. In combination with cosmological simulations, we can derive constraints on the origin of cosmic magnetism. Low-frequency radio observations have shown that clusters of galaxies can host huge reservoirs of cosmic rays, in a phenomenon that we have called megahalos.

We used more than 25 million galaxies in the Subaru Hyper Suprime-Cam (HSC) shear catalog in the redshift range up to z~1.5 to measure weak lensing distortion effects due to large-scale structures. We used the measured weak lensing signals to perform a blinded cosmology analysis to measure the cosmological parameters of the flat LambdaCDM model. To obtain a robust constraint on the cosmological parameters, we employed a uninformative flat prior to model a possible residual systematic error in the mean redshift for  HSC galaxies at z>1. As a result, we were able to measure the “S8” parameter at a 4% accuracy (sigma(S8)~0.04), but the central value exhibits about 2.5sigma tension with the Planck inferred S8 value. Our results indicate a non-zero residual error in the mean source redshift compared to the photometric redshift estimates for the HSC galaxies at z>1. In this talk, I will discuss the HSC cosmology results, and, if time is allowed, present the current status of the upcoming Subaru Prime Focus Spectrograph project, which promises significantly improvement of the HSC cosmology results.

Over the last two decades the important of binaries in understanding stellar populations has become widely recognized. However, the physics of interactions in binary stars has many open questions and uncertainties. In this talk I will outline how we can use electromagnetic and gravitational wave observations across cosmic history to constrain these uncertainties. I will focus on recent results from the Binary Population and Spectral Synthesis (BPASS) code. Showing that because BPASS differs from other similar codes in the treatment of binary interactions we can gain new insights into the physical processes of binaries. With these results allowing us to understand, stars, galaxies and the Universe with greater accuracy.

Over the past 20 years it has become increasingly clear that supermassive black holes are essential components of galaxies, as demonstrated by the correlations connecting black hole masses and large-scale galaxy properties. Although about ~100 dynamical black hole mass measurements have been made to date, the local black hole mass census is highly incomplete. Gaining a more complete picture of black hole demographics and a deeper understanding of the mechanisms that drive black hole - galaxy co-evolution requires the measurement of black holes in a wider range of galaxies with diverse evolutionary histories. I will discuss several recent and on-going programs aimed at taking this necessary step, as well as the observational and modeling advances that have made the work possible.

We use the oldest stars born in-situ in the Milky Way to study its chaotic and turbulent pre-disk state that we dub Aurora. Through the chemo-kinematic analysis of the local stars we reveal the Galactic spin-up, i.e. the emergence of the Milky Way's stellar disk. The Galaxy's transition from Aurora to a stable and dominant disk is accompanied by a variety of additional phenomena: i) a marked drop in the fraction of star formation locked in massive star clusters, ii) a large reduction in elemental abundance spread, and iii) a change in the slope of the stellar metallicity distribution.

We compare the observed properties of the high-redshift Milky Way to the results of numerical simulations of galaxy formation and discuss the implications of our study.

Pushing the Hubble Space Telescope to its limits at the end of the last decade has allowed astronomers to view the tip of the cosmic iceberg at a time only 500 Myr after the Big Bang.  While a few candidate galaxies were found, significant questions about the onset and evolution of the earliest galaxies persisted.  The launch of JWST has opened up this epoch to direct and detailed observation by providing a significant leap in our ability to study the entire epoch of reionization due to its redder sensitivity and spectroscopic capabilities.  The Cosmic Evolution Early Release Science (CEERS) and Next Generation Deep Extragalactic Exploratory Probe (NGDEEP) programs have enabled one of our first looks into this epoch, finding that galaxies at z > 9 are more abundant than predicted by most simulations.  This hints at not only an early onset of galaxy formation, but that stars are forming differently at these early times (at higher efficiency and/or with different initial mass functions).  The CEERS spectroscopic program has shown that photometric redshifts *work*, with a high fraction of spectroscopic confirmations, and only one (interesting, yet rare) case of contamination.  These data have also significantly improve our ability to identify early growing supermassive black holes, showing that they appear (relatively) frequently at high-redshift, including a remarkable AGN at z=8.7.  These observations pushing models of early black hole growth, implying that massive seeds and/or super-Eddington accretion are needed at early times.

A satisfying theory for star or planet formation should not consider these processes in isolation. Leveraging advances in computations and large observational surveys, we are well-positioned to test detailed theoretical models of stellar system formation across diverse galactic environments. We are beginning to couple our understanding of the earliest phases of star formation with the onset of planetary system formation, considering the growth of planets embedded in their natal disks. In this talk, I will review joint constraints on planet formation and star formation. I will highlight how broad demographic trends inform our understanding of the importance of different physical mechanisms. Finally, I will illustrate the outsize impact of small dust grains on the detectability and early evolution of young planets.

Galactic Globular Clusters were for decades considered as the archetype of simple stellar populations and, as such, they were widely used as testing benches for the modelling of stellar evolution and population synthesis tools. 

The past twenty years have, however, brought a veritable revolution in our understanding of these objects: we now know that they host multiple stellar populations, with varying characteristics. In spite of considerable effort on the matter in the past two decades, a coherent comprehension of the processes that lead to the formation of these objects is still elusive, with proposed scenarios being challenged by observational evidence. In this talk, I will review the current understanding of phenomenon, focusing in particular on the multifaceted evidence arising from the study of the composition of the multiple stellar populations. I will also discuss on some of the key open issue in this context and explore how the upcoming large spectroscopic surveys (e.g. 4MOST, WEAVE, SDSSV) might impact this topic.

The Large scale Structure of the Universe is organised in a Cosmic Web made of voids, sheets, nodes, and filaments that are well traced by the distribution of galaxies. Numerical simulations suggest that the filamentary structure between clusters of galaxies at the nodes of the Cosmic Web contains about 40% of the total baryons in the form of a hidden ionised warm/hot component.

I will present how we can combine the use of surveys in the optical, in the millimetre (via the Sunyaev-Zel'dovich and CMB-lensing signals measured by Planck), and in the X-rays to study the filamentary structure of the Cosmic Web and to unveil its content. Combining these observables, we have detected the Cosmic Web filaments and we have tackled the problems of measuring their warm/hot baryon content and of characterising its properties.

Supermassive black holes of 10^10 solar masses already existed at z~6-7, when the Universe was less than 1 Gyr old. To reach this mass in such a short time they should have started as seed intermediate-mass black holes (IMBHs) of 100-10^6 solar masses at z > 8.

I will show that a population of actively accreting IMBHs exists in local dwarf galaxies and that they can be detected out to z~3 with the use of deep multiwavelength surveys. Whether these are the relics of those early seed black holes that did not grow into supermassive is still a matter of debate, since processes such as dwarf galaxy mergers and black hole feedback can have a very strong impact on black hole growth. The next generation of observational facilities could open a new window by detecting seed IMBHs at birth. 

The Canadian Cosmological Hydrogen Intensity Mapping Experiment (CHIME) is an ambitious new approach for rapid surveying of the radio sky.  The first results from its time domain back end include the leading discovery machine for fast radio bursts, resulting in large catalogs to study their nature and open up coherent applications for precision cosmography.  I highlight some results from synergy with follow-up collaborations, including the connection to globular clusters, periodicity, and polarization.  Other survey modes include 21cm mapping in emission and absorption, polarimetry, pulsar studies, and direct VLBI.  This opens the path for a next generation of more ambitious all sky surveys, of which I will describe the ongoing BURSTT initiative.

State-of-the-art 3D simulations lend support to the neutrino-driven explosion mechanism for explaining the majority of core-collapse supernovae. Using this paradigm it has been shown that 3D explosion models can explain the multi-band light curves and spectra of low-energy Type IIP supernovae such as Crab; they can also reproduce basic elements of the 3D morphology and the gamma-ray lines of the Cassiopeia A remnant; and they provide new hints on the binary nature of the SN 1987A progenitor and the most likely location of the compact remnant in its ejecta nebula. The talk will summarize this progress of 3D supernova modelling and will outline the open questions and routes of ongoing research.

The newly launched James Webb Space Telescope (JWST) has expanded our cosmic horizon to the first few hundred million years after the Big Bang, enabling us to observe the build up of the first galaxies. These first galaxies fundamentally altered their surroundings by 're'-ionizing intergalactic hydrogen. I will describe how this reionization process is still poorly understood, but how identifying which population of galaxies dominated the process is key to constraining poorly understood astrophysics of galaxy formation (e.g. massive star formation and feedback processes). Excitingly, an excess of luminous galaxy candidates just 500 million years after the Big Bang has been discovered in early JWST data, which exceeds theoretical predictions. I will discuss how the new JWST observations test theoretical models and possible solutions. I will present efforts to constrain the timeline of reionization, which favour a late and rapid end to reionization. I will discuss how JWST observations of Lyman alpha emission at z>8 challenge these results and discuss the implications for our understanding of early star formation.

Line-Intensity Mapping (LIM) is an observational technique that uses integrated emission lines from gas clouds to extract information about cosmology and extragalactic astrophysics. Unlike galaxy surveys, this technique samples even the sources which are not so bright and can reach very high redshifts to probe very large cosmological volumes. In order to extract valuable information from upcoming LIM surveys, we will need robust models to infer astrophysical/cosmological parameters from observed luminosities. In this talk, I will give an overview of the field, and present the framework I have been developing to contribute to LIM modeling. I generate LIM light cones fully based on cosmological hydrodynamic galaxy formation simulations, combined with thermal/radiative/chemical equilibrium photodissociation region (PDR) models to calculate the spectral line luminosities from every gas particle in the snapshots. In addition, I will show an application of this framework using the SIMBA simulations to generate CO and [CII] mock light cones.

Gas is a fundamental component of galaxies and its chemical composition is key for the chemical evolution of galaxies and the cosmic chemical evolution. The metal content of the neutral gas inside and around galaxies (Interstellar and Circumgalactic Medium) can be probed in great detail with absorption-line spectroscopy of stars in the Local Group or distant quasars and gamma-ray bursts (GRBs). However, the presence of dust dramatically alters the observed metal abundances, because of the depletion of metals into dust grains. I developed a technique to derive metallicities, dust depletions, and additional nucleosynthesis signatures in the gas from the observed relative abundances of metals, based on the fact that different metals have different tendencies of depleting into dust, and different metals have different nucleosynthetic origins. This is key for a deeper understanding of the chemical content of the neutral ISM/CGM in galaxies and allows us to start addressing new questions. What is the metallicity of the neutral ISM in our Milky Way? Are metals distributed uniformly in galaxies? Can we observationally study the chemical evolution of distant galaxies? How does the metallicity in the neutral gas evolve with cosmic time? What is the role of massive stars in the chemical enrichment of the early universe, and how can we observe it? In this talk I will review exciting results addressing these questions. 

Fifty years ago, Bekenstein recognized a profound relation between spacetime geometry and quantum information: a black hole carries entropy, in proportion to the surface area of its horizon. This implied that Einstein’s seemingly classical theory of gravity can count its own quantum states, and those of matter.

Today, the entropy-area relation has been vastly generalized, driving a golden age of progress. Gravity has been used to show that the universe behaves like a hologram; that information escapes from a black hole; and that what we perceive as energy density is really a change in the flow of quantum information.

The last decade of ALMA has transformed our view of planet-forming environments in all respects. High resolution images have revealed a diverse array of structured belts of millimeter-sized dust and a variety of distinct molecular compositions both within disks and between different disk systems. How does this diversity translate into the initial conditions for the formation of planets and the compositions (gas and solid) that they receive? Are planets likely to receive water and organic material at formation, or at some later phase from a belt of volatile-rich icy comets? I will present an overview of how our picture of the chemical and physical environment of planet formation has shifted in recent years, how this has pushed us to revise models, and how multiwavelength observational campaigns, including upcoming JWST programs, can help us find patterns in the apparent variety of protoplanetary environments.

Most studies of galaxy formation suggest that merging supermassive binary black hole systems should be reasonably common in galactic nuclei, but LISA, the observatory with the most robust detection method, remains at least a decade in the future.  On the other hand, there are good reasons to expect that many of these binaries accrete gas at a sizable rate. Such a situation motivates searches for them now, using photon telescopes, but there is much uncertainty about what signatures are both reliable and detectable.

In this talk, I will review the various suggestions made hitherto and then present a summary of the light that has been shed on this question by recent numerical general relativistic magnetohydrodynamics simulations, some of them following the evolution of the binary very nearly all the way to merger.  These simulations have uncovered entirely new accretion pathways as well as new ways to power photon emission.

Neutral atomic hydrogen (HI) is a crucial component of the Milky Way and a protagonist in the cycles of energy and matter that lead to the formation of stars. I will present a study of the filamentary structure identified in the HI emission at 21 cm using the HI4PI and the HI/OH/Recombination-line (THOR) surveys of the Galactic plane. We found that the Milky Way’s disk regions beyond ten kiloparsecs and up to roughly 18 kiloparsecs from the Galactic center display HI filamentary structures predominantly parallel to the Galactic plane. However, we also found that the HI filaments are mostly perpendicular or do not have a preferred orientation with respect to the Galactic plane for regions at lower Galactocentric radii. Using the insight from numerical simulations, we interpret these results as the imprint of supernova feedback in the inner Galaxy. We also studied the carbon monoxide (CO) emission observations from The Milky Way Imaging Scroll Painting (MWISP) survey. We found that the orientations of the filamentary structures traced by CO emission differ from those in the HI emission. We interpret this result as indicating that the molecular structures do not simply inherit these properties from parental atomic clouds. Instead, they are shaped by local physical conditions, such as stellar feedback, magnetic fields, and Galactic spiral shocks.

Planetary systems are found to be a very common outcome of the star formation process, but the diversity of planetary architectures is stunning. The analysis of the Solar System as we know it today provides detailed insights into its formation history. One of the major questions in the field of planet formation is how widespread these conditions and history are. In this talk, I will try to address this question based on what we have been and are learning about planet formation based on the study of protoplanetary disks in nearby star-forming regions. I will discuss the constraints on the evolution of solids and volatiles in protoplanetary disks and compare these with what we think were the conditions in the young Solar System. I will also try to highlight the major open questions in the field and where we hope to make progress in the near future. 

Most of about 60 known stellar-mass black holes were found in binaries (X-ray binaries and GW mergers). Gravitational microlensing is the only tool capable of detecting single black holes, which are not interacting with anything. I will present our long-term project aiming at discovering and studying the microlensing black holes with the OGLE, Gaia and forthcoming Rubin/LSST surveys. Microlensing non-detections towards the Magellanic Clouds have put strong limits on the compact dark matter content in the Galaxy Halo, while the statistical studies of microlensing events towards the Galactic Centre, revealed a continuum of masses of dark lenses and hint at a lack of the mass gap between neutron stars and black holes.

However, in order to study individual events and obtain the masses of individual lenses it is crucial to measure the size of the Einstein Radius, which defines a separation between the lensed images and is a physical parameter degenerated in the classical microlensing light curve model.  This is possible en masse only with the Gaia space mission, which scans the entire sky and is providing not only brightness and colour temporal evolution for nearly 2 billion stars but also positional time series with sub-milliarcsecond precision. I will describe how we search for on-going microlensing events within daily Gaia data using Gaia Science Alerts system and how their photometric, spectroscopic and interferometric follow-up is conducted.

I will present the first candidates for dark lenses from Gaia and then describe how these lessons learnt can be applied to the forthcoming Rubin/LSST survey and GRAVITY+ instrument.

Over the last decade, our understanding of classical novae has been turned on its head with the discovery of gamma-rays from Galactic eruptions. This discovery has highlighted the value of novae---non-terminal, thermonuclear eruptions on the surfaces of white dwarfs in binary systems---as laboratories for studying shocks and particle acceleration. I will discuss where and how shocks form in the nova ejecta, why we think the shocks may actually dominate the energy budget of the nova eruption, and some of the consequences of the shocks, including dust formation and acceleration of particles to very high (TeV) energies. These recent developments place novae amongst the ranks of interaction-powered transients, making them nearby, common examples of the physics that governs more exotic events like Type IIn supernovae, stellar mergers, and tidal disruption events.

I will show first science results from the MeerKAT Fornax Survey. Our goal is to perform a detailed study of the nearby Fornax galaxy cluster in order to understand how galaxies lose their cold gas and stop forming stars in low-mass clusters (Mvir < 1e+14 Msun). We are doing so through very deep (down to ~1e+18/cm^2) and high resolution (up to ~ 1kpc and 1 km/s) MeerKAT observations of HI gas in a 1x2 Mpc^2 region centred on Fornax.

Our survey started in October 2020 and is now 50% complete. These first data focus on the central region of the Fornax cluster and reveal for the first time the ubiquitous presence of tails and clouds of HI. Some of the HI is clearly being removed from Fornax galaxies as they interact with one another, with the intra-cluster medium and/or with the large-scale gravitational potential. I will present a sample of galaxies with long, one-sided, star-less HI tails (of which only one was previously known) radially oriented within the cluster and with measurable internal velocity gradients. The properties of these tails represent the first unambiguous evidence of ram pressure shaping the distribution of HI in the Fornax cluster.

Women hold a very low portion of professorships in science, such as in chemistry, physics, mathematics, engineering and computer science. Why are women who are talented and dedicated enough to graduate from college not progressing through graduate school and ultimately earning full professorships? Where are these women going, and why do they leave their chosen field?

Much has been written about the underrepresentation of women professors in science, particularly in upper-level positions. Despite the substantial amount of high-quality data on this issue, however, myths and misunderstandings prevail. A frequent claim is that women are derailed by sex discrimination in publishing their work, obtaining grant funding and being hired. However, although these forms of discrimination have played important roles in the past, the current data show that  none of these causes can explain today’s underrepresentation. 

In this talk, I will review the most recent evidence showing that gender itself is no longer responsible for the current dearth of women in science. I will argue for the importance of another factor in women’s underrepresentation: the choice to become a mother. To place the role of this choice in context, I will consider its impact on women’s careers relative to the impacts of other variables that may reduce women’s participation in the sciences. I will show that recent findings indicate that the effect of children on women’s academic careers is so remarkable that it eclipses other factors in contributing to women’s underrepresentation in academic science.

Key factors that limit women today are still in need of solutions. Understanding the actual cause of women underrepresentation in academy is the first necessary step to create solutions to target the real issue.

Over the past decade hundreds of galaxy candidates have been identified in the Epoch of Reionization (EoR), selected from their rest-frame UV light. Until the advent of ALMA and JWST, only a handful of these sources had spectroscopic redshift determinations and we still have limited understanding of their observational and physical properties. Over the last few years ALMA has already been transforming this field by identifying massive ISM reservoirs at z>6 from bright [CII] line emission, while JWST is now opening up an entire new window onto these first galaxies too. 

I will describe how we obtained the first spectroscopic confirmations of galaxies in the EoR with ALMA; pilot studies which led to the execution of the ALMA Large Program REBELS, the first systematic study of luminous galaxies in the Epoch of Reionisation. The ALMA follow-up studies of these programs put new constraints on the dust-buildup, kinematics, and ISM conditions of z~7 galaxies, often finding surprisingly evolved systems. I will discuss some of the surprises that ALMA has uncovered and I will compare and contrast our findings to the newest data from JWST, in order to give insight into what we might expect from the upcoming decade of ALMA+JWST observations.

The Imaging X-ray Polarimetry Explorer (IXPE), a NASA/ASI mission, is the first satellite dedicated to study the polarization of cosmic sources in the X-ray band. Launched in December 2021, in its first year of operation is providing several very interesting - and in some cases rather surprising - results on many different classes of X-ray sources.

In this talk, the mission will be described and the most important results discussed.