Colloquium on Apr. 22, 2021

Galaxy Formation Simulations for Cosmology with Emission Line Galaxies

Speaker:Ken Osato (YITP, Kyoto; ENS Paris)

Venue:Video Conference

Time:16:00 PM, Thursday, Apr. 22, 2021

Abstract:

In order to investigate the structure formation and evolution at the distant Universe, emission line galaxies (ELGs) are suitable target for upcoming spectroscopic surveys because they are easily identified with strong emission line and the redshift is robustly determined. At large scales, spatial distribution of ELGs well traces underlying density field with linear bias relation. This simplified relation, however, breaks down at smaller scales due to complex non-linearity relevant to formation of ELGs. The strong emission line of ELGs is sourced by short-lived massive stars, and thus, clustering of ELGs reflects star formation activity, i.e., assembly history of host halos or environment of the formation site. Therefore, modelling of ELG clustering is an important but challenging task to explore full capabilities of future spectroscopic surveys.

In order to address clustering properties of ELGs, we utilise galaxy formation hydrodynamical simulations: IllustrisTNG. We have developed the scheme to simulate emission line intensity from each galaxy with stellar population synthesis code. In simulations, we can directly investigate the relation between properties of ELGs and host halos and measure the cosmological statistics, e.g., correlation function. We address how biased inferred cosmological parameters are with the measured correlation function when the standard linear bias relation is employed and scrutinize galaxy-halo connection. Finally, if time permits, we also present a fast method to generate mock ELG catalogs from N-body simulations based on local density.

Report PPT:SWIFAR_Ken Osato.pdf