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

I’m focusing my work on observations of the Lyman-α forest and its cosmological as well as astrophysical interpretation using cosmological simulations.

Currently I’m involved in the Dark Energy spectroscopic instrument (DESI) survey working 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 Σm_ν and inflationary parameters. Furthermore, I am working on improvements of the CCD level calibrations for DESI within the desispec project and am (together with our local PhD student Parth Nayak) investigating new approaches of Lyα forest analysis based on machine learning techniques.

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

ADS: click here

0000-0002-1748-3745

CV

Overleaf: click here