Seminars and Colloquia at ESO Garching and on the campus

The main DESI redshift surveys have now collected 3 years of data and analysis of the Year-1 data set is almost complete. While concentrating  on the analysis of the Bright Galaxy Survey (BGS) in which I'm most directly involved  I plan to review the main cosmological results from other components of DESI. The BGS is a magnitude-limited (r<19.5) galaxy redshift survey and so rather like the SDSS main survey but about two magnitudes deeper. As such it is not only a useful cosmological probe but also a powerful probe of the local galaxy population and so a constraint on galaxy formation and the galaxy dark matter connection. I will present an analysis of how galaxy clustering depends on galaxyproperties and the galaxy luminosity function depends on environment.

On their way from the main sequence to the final supernova explosion, massive stars lose a substantial fraction of their mass through line-driven winds. Recent decades have witnessed significant advancements in both observational and theoretical studies of these winds that sail on starlight. The advancements in our understanding of radiative driving lead to progressively more accurate estimates of mass-loss rates from massive stars. In this talk, we will outline the key ingredients necessary for reliable predictions of mass-loss rates from numerical simulations, and demonstrate how state-of-the-art theoretical mass-loss rate estimates compare with observational results.

It is creativity/novelty that drives scientific breakthroughs and societal progress, but the journey from a novel scientific idea to a practical solution can be long and winding. Debates also persist regarding whether and how science contributes to practical solutions. In his talk, Jian will explore the complex relationship between novelty and impact in science and technological innovation. Furthermore, he will examine concerns that the current science funding system is increasingly risk-averse and favours short-term, safe projects over long-term, risky and novel projects. He will also present empirical evidence about whether major funding agencies are biased against novelty in their project selection process, and whether receiving funding enables grantees to engage more in novel research. Finally, he will discuss strategies that scientists can use to boost creativity, such as how to structure the professor-PhD student relationship, collaboration teams, and broader collaboration networks.

You can find the abstract and a short bio by the speaker at:

https://indico.euro-fusion.org/event/2559/page/18-highlight-topic-creativity-in-science

High resolution, hydrodynamic galaxy simulations can be used to investigate the inherent variation of dark matter around the Solar Circle of a Milky Way-type galaxy. These simulations self consistently include both the baryonic back-reaction as well as assembly history of substructures, all of which may have lasting impacts on the dark matter’s spatial and velocity distributions, creating `gusts’ of dark matter wind around the Solar Circle, potentially complicating interpretations of direct detection experiments on Earth. Direct detection is a key experimental goal to advance the microscopic understanding of the dark matter that fills the Universe. We investigate how dark matter substructure, simulated in halos analogous to our own Milky Way, impacts the shape, summary statistics, and interpretation of results from terrestrial dark matter direct detectors.

Implementing a new numerical integration technique, our work generates bespoke predictions for terrestrial underground detection, finding large uncertainties arising in the expected signals of direct detection experiments. Having developed a realistic end-to-end pipeline for studying these effects, we discuss the implications of these astrophysical variations in the dark matter distribution of the solar neighbourhood on current and future particle physics searches for dark matter.