Main Colloquium
Dr. Sebastian Bocquet	SCHEDULED

LMU

With the latest generation of cosmological datasets, we are accessing an unprecedented wealth of information on the geometry and expansion of the universe and on the growth of cosmic structure. This has allowed for tight constraints on, e.g., the properties of neutrinos and dark energy, but also uncovered anomalies such as the Hubble tension and the S8 tension. The abundance of galaxy clusters, the clustering of galaxies, and weak gravitational lensing are key probes of the cosmic large-scale structure. Over the past decade, tremendous progress was made in obtaining high-precision measurements, notably thanks to sensitive wide-field surveys of the cosmic microwave background (CMB) and of galaxies and gravitational lensing. Recently, the abundance of clusters selected in CMB data from the South Pole Telescope (SPT) — in combination with mass calibration based on weak-lensing data from the Dark Energy Survey (DES) and the Hubble Space Telescope (HST) — was shown to be compatible with and complementary to analyses of galaxy clustering and weak lensing (3x2pt using, e.g., DES data). In my talk, I will review the SPT cluster cosmology and mass calibration program. I will focus on the latest SPT + DES + HST analysis and discuss the resulting cosmological constraints. I will then present new results from the multiprobe analysis of SPT clusters and DES 3x2pt. The precision of these new constraints highlights the benefits of multiwavelength multiprobe cosmology and our work paves the way for upcoming joint analyses of next-generation datasets.

	Master Colloquium
Camilla di Giusto	SCHEDULED

MPIfR

Sulphur-bearing species could be used as evolutionary tracers of high-mass star formation. In this context, we studied the molecular emission and absorption of S-bearing species towards Galactic high-mass star-forming clumps. We analyzed spectroscopic observations obtained with the APEX telescope and the SOFIA mission towards 131 clumps of the ATLASGAL survey at 870 μm. Among those, the ATLASGAL "Top100" sample contains the brightest sources in all evolutionary stages of the high-mass star formation process. We detected rotational line transitions of ortho-H2S, para-H2S, OCS, SO and H2CS. While most of the spectra showed single Gaussian emission, signatures of outflows, self-absorption and infalling/expanding envelopes were also found. Assuming LTE conditions, the column densities and abundances of each species were derived. The species abundances showed a loose correlation with the luminosity and evolutionary stage of the clumps. In addition, the ortho-to-para ratio (OPR) of H2S was determined using H2S low frequency lines but found to be degenerate with temperature. By assuming a thermalized OPR value of 3, temperatures of the order of 100 K were found for the H2S emission, pointing to a hot core origin. The spherical non-LTE radiative transfer model RATRAN was used to study the H2S line profiles. However, the model did not reproduce well the observed spectra suggesting a more complex source morphology.

	Main Colloquium
Dr. Reza Ayromlou	SCHEDULED

University of Bonn

TBD

	Master Colloquium
Parisa Rahimi	SCHEDULED

MPIfR

The BRAND receiver is a new system mainly intended for the EVN that covers the remarkably broad contiguous frequency range of 1.5 GHz to 15.5 GHz. It includes all required components of the entire signal path from the cryogenic frontend, feed, amplifiers, hybrids, a 56 Gsps sampler down to the VLBI backend and is intended for VLBI and single-dish work. This band coverage offers flexibility for redshifted spectral lines, sensitivity and frequency agility in the EVN. In my thesis I present the integration tests recently carried out an initial commissioning of the BRAND components into a prototype system installed in the Effelsberg 100 m telescope. This continues the development from the RadioNet BRAND-EVN project. This work is based on technical tests on the cryogenic-, IF-, and data-acquisition system in Bonn and Effelsberg. On-sky tests include single-dish spectroscopy and VLBI resulting a 1.5 to 12 GHz bandwidth spectrum of W3 cloud and VLBI fringes on all baselines. The first on-sky measurements with the latest and broadest-band member in the family of broad-band receivers (C/X with fractional bandwidth of 80 %, UBB with 130 % and BRAND with 165 %) have been done. Cross scans and Moon observations have resulted in a $T_"sys"$ of around 90 K. From the spectrum of the W3, 57 radio recombination lines were detected, and from a VLBI session between four EVN stations, fringes were detected. This has allowed an assessment on the real-world performance in various scenarios, e.g. astronomical as well as geodetic VLBI and single-dish applications and should help inform the decision-making about future EVN capabilities.

	Main Colloquium
Dr. Giulia Illuminati	SCHEDULED

INFN-Bologna

KM3NeT is the next-generation neutrino observatory currently under construction in the Mediterranean Sea, already taking data in a partial configuration. By covering a vast energy range with its ARCA and ORCA detectors, KM3NeT can investigate a variety of scientific topics, including neutrino astronomy, oscillation studies, and dark matter searches. I will present the recent results in all these fields and discuss the exciting prospects KM3NeT offers for advancing our understanding of the cosmos and the fundamental properties of neutrinos.

	Main Colloquium
Andreas Quirrenbach	SCHEDULED

TBD

	Main Colloquium
Dr. Markus Boettcher	SCHEDULED

North-West University, Potchefstroom, South Africa

TBD