Computational Cosmology: new high redshift galaxy observations

Abstract

When firstly studying the large structure formation from a cosmological perspective it was found that it required the use of simulations to compute the high number of calculations. Nowadays, cosmological simulations are used to discern between different cosmological models through comparison with the observational data. In recent years, Cosmology is entering into an era of precision with goals to drastically reduce the uncertainties of the observations. This will possibly challenge our knowledge of the Universe. In this work, how the newest observations fit inside the current cosmological model has been studied. To do this I have learnt how to use GIZMO by running small cosmological simulations and Rockstar to analyse their results. After this, and using a set of larger simulations, the HMF was obtained and, through an abundance matching with the GSMF from observational data, the stellar-to-halo mass fraction. The observational data at very high redshift used came from the JWST. It was found that the evolution of the HMF and the stellar-to-halo mass fraction was consistent with the current model. On the other hand, the data from the JWST showed bigger stellar masses than what was expected at z = 10, showing that star formation should have started before or had been faster than what was thought to be. In conclusion, the JWST data seems to defy the current cosmological model, but the uncertainties do not exclude an agreement between both and more precise observational data is needed to give a clearer answer.