Speaker
Description
The large-scale structure of the universe provides valuable information on the fundamental
laws governing its evolution. This structure consists of a network of immense galaxy filaments,
separated by vast cosmic voids, forming an intricate pattern known as the cosmic web, which
is shaped by gravity. To study and better understand these phenomena, cosmologists employ
computational simulations utilizing sophisticated numerical codes to reproduce the evolution
of the universe. One such code is GLASS.
GLASS (Generator for Large Scale Structure) is a novel simulation code for galaxy surveys
in cosmology. It iteratively constructs a light cone, incorporating matter, galaxies, and weak
gravitational lensing signals as a sequence of nested shells.
This project focuses on the implementation of Line-Intensity Mapping (LIM) in GLASS,
with particular emphasis on the HI 21 cm emission line. LIM is an emerging field in physical
cosmology that measures the integrated emission from spectral lines in galaxies and the diffuse
intergalactic medium (IGM) to trace the growth and evolution of cosmic structures.
We model the HI 21 cm signal using the mean neutral hydrogen temperature to generate fullsky
maps of brightness temperature fluctuations. From these maps, we compute the angular
power spectrum Cℓ and compare it with theoretical expectations. We then correlate these
spectra with those from galaxy clustering, revealing a strong complementarity between the
distributions of galaxies and neutral hydrogen.
As a next step, we plan to extend the analysis to more realistic observational scenarios by
incorporating real survey data distributions, such as those expected from MeerKLASS.
