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Michael Walther
Hi, I’m Michael Walther, a postdoctoral researcher in the group for Astrophysics, Cosmology and Artificial Intelligence at the university observatory Munich, which is part of Ludwig Maximilians University, Munich, Germany. Previously I worked at CEA Saclay, France, UC Santa Barbara, US and MPIA Heidelberg, Germany.
Work topics
Currently, I am the coordinator of the AI in Physics specialization program, which is part of the LMU physics MSc degree. I also organize the AI Lab course, which is a mandatory course within this specialization, and have been teaching students in multiple labs and seminars on topics in AI and cosmology.
Scientifically, I have focused my work on observations of the Lyman-α forest and its cosmological and astrophysical interpretation using cosmological simulations as well as fast emulation techniques.
I am involved in the Dark Energy Spectroscopic Instrument (DESI) survey, where I focus on measurements of the Lyα forest power spectrum based on observations of high-redshift quasar spectra. To simulate the intergalactic medium that creates this forest, I also performed hydrodynamical simulations with the Nyx code of up to 40963 resolution elements (see here for a video showing the evolution of a single slice through a box). The main goal of this work is to obtain more accurate constraints on warm dark matter (WDM), the neutrino mass Σmν, and inflationary parameters. Within the DESI collaboration, I co-led the topical group for Lya forest analysis software development. I’m currently co-leading the analysis on the 1D power spectrum of the Lyman-alpha forest.
Furthermore, I was working on improvements of the CCD level calibrations for DESI within the desispec project, on obtaining accurate Galaxy redshift measurements using redrock (together with previous master student Shirsh Chhabra), and am studying the information contained in Lyα forest statistics (with master student Sookyung Chang) and more optimal ways to constrain parameters using machine learning (together with PhD student Parth Nayak and master student Uday Nakade).
Previously, I have been working on constraining thermal evolution in the intergalactic medium using high-resolution Lyα forest observations from the VLT/UVES and Keck/HIRES spectrographs.
Publications
Publication list: link to astrophysics data system
0000-0002-1748-3745CV
Short CV: link to overleaf
Long CV: link to overleaf