Main Colloquium
Professor Caroline Heneka	SCHEDULED

University of Heidelberg

The era of radio astronomy is rapidly transforming as next-generation instruments, in particular the Square Kilometre Array (SKA), begin to map vast portions of the observable Universe. These surveys generate enormous and complex datasets, from millions of galaxies across cosmic time to mappings of the intergalactic medium and large-scale structure via the 21cm background during the Epoch of Reionization. Modern AI and machine learning methods are becoming essential for extracting scientific insight from these data. In this talk, I will highlight how flexible, data-driven approaches enable robust scientific analyses across the full workflow from simulations and observational modeling to inference, and show how they help to gain insights on galaxy evolution, the properties of the intergalactic medium, and fundamental physics, while accelerating discovery across large radio surveys.

	SFB Colloquium
Prof. Amelie Saintonge	SCHEDULED

MPIfR

TBD

	Master Colloquium
Josephine Benna	SCHEDULED

MPIfR

Canonical wisdom has the molecular gas in galaxies distributed following simple exponential profiles, with a half-light radius related to the optical size. There is however ample evidence that this is an over-simplification, with actual molecular gas distributions displaying a much broader range of shapes and sizes. In this thesis I calculate the non-parametric morphology parameters Concentration, Asymmetry, Smoothness, Gini, and the moment of light (CASGM) for all detected galaxies in the KILOGAS sample using the high-resolution CO(2-1) observations from the Atacama Large Millimetre/submillimetre Array (ALMA) to quantify the morphology of the molecular gas in nearby disc galaxies, and investigate its connection to global galactic properties. I do this through the use of statistical methods such as the spearman rank coefficient and a random forest regression.

	Special Colloquium
Prof. Andrew Zentner	SCHEDULED

University of Pittsburgh, USA

Dark matter halos provide the gravitational framework within which galaxies form and evolve, and thus underpin the observed large-scale structure of the Universe. Within the cold dark matter (CDM) paradigm, the growth and clustering of halos are well understood in broad terms, making halo clustering a natural starting point for understanding galaxy clustering. While halo clustering has long been known to depend strongly on halo mass, it has become clear over the past two decades that halos also cluster differentially at fixed mass as a function of additional properties such as formation time, concentration, and accretion history. This phenomenon, commonly referred to as assembly bias, has important implications for models of the galaxy–halo connection. If galaxy occupation depends on halo properties beyond mass alone, then mass-only models cannot describe galaxy clustering at high precision, potentially introducing both scatter and systematic biases into inferred galaxy–halo relations and cosmological constraints. I will briefly review the theoretical origin of assembly bias and its impact on halo and galaxy clustering. I will then present two recent observational detections of halo assembly bias in SDSS and DESI data obtained by my collaborators and me, and argue that these signals provide direct, testable evidence for environment-dependent halo and galaxy evolution. I will then introduce a new aspect of assembly bias related to satellite systems. Large galaxies are surrounded by populations of satellite galaxies whose spatial distributions are often highly anisotropic. Using numerical simulations within the CDM framework, I will show that subhalos around host halos are distributed far more anisotropically than the underlying dark matter. I will further present recent results demonstrating that host halo clustering depends on the degree of anisotropy or planarity in their satellite populations, implying a clear environmental dependence of satellite configurations. These findings may have important implications for observational tests of satellite anisotropy and for other large-scale structure observations such as intrinsic alignments in weak gravitational lensing.

	Main Colloquium
Prof. John McKean	SCHEDULED

Kapteyn Astronomical Institute, University of Groningen & ASTRON, Dwingeloo, The Netherlands

Gravitational lensing provides a powerful probe of the global mass properties of galaxies, which are best tested using observations at extremely high angular resolution. In addition, through detailed observations of the lensed images, it is possible to place tight constraints on the nature of dark matter through measuring the abundance and properties of low mass haloes via their subtle gravitational lensing signal. Here, we first present new observations with the VLA and HSA to better understand the source of so-called flux-ratio anomalies in four image gravitational lenses, which historically provided the first constraints on CDM using lensing studies. Next, we will present the analysis of the mass properties of ten massive elliptical galaxies at intermediate redshifts, by combining gravitational lensing and the sensitivity and resolving power of the Atacama Large Millimetre Array (ALMA) and global Very Long Baseline Interferometry (radio VLBI). Using imaging at 25 to a few milli-arcsecond resolution, we find that complex mass models with angular structure are strongly favoured by the data. In addition, such observations are sensitive to small-scale structure either in the lens or along the line-of-sight to the background source. From such an analysis of the data from global VLBI observations, we detect of a low mass (million solar mass) dark object, whose properties are inconsistent with a dark matter halo from either cold or warm dark matter models, but may be in agreement with more exotic models, like self-interacting dark matter. Finally, we present a brief overview of future studies using the SKA and a likely African VLBI facility that includes the SKAMPI, MPG-DZA and AMT dishes. Throughout we will also provide some asides on the pc-scale structure of radio jets, constraints on galactic-scale magnetic fields and electron densities, and the super-resolved (about 10 to 20 pc-scale) properties of starburst galaxies at redshifts 1 to 4.

	Main Colloquium
Professor Axel Brandenburg	SCHEDULED

The Nordic Institute for Theoretical Physics (Nordita), Sweden

TBD

	Main Colloquium
Dr. Eda Gjergo	SCHEDULED

Wuhan University, China

TBD