Redshift Drift fluctuations from N-body simulations

Measurements of the redshift drift -- the real time variation of the redshift of distance sources -- are expected in the next couple of decades using next generation facilities such as the ANDES spectrograph at the ELT and the SKAO survey. The unprecedented precision of such observations will demand precise theoretical and numerical modeling of the effect in the standard $\Lambda$CDM cosmology. In this work, we use the \texttt{Gadget4} $N$-body code to simulate the redshift drift and its fluctuations in $\Lambda$CDM cosmologies, deriving the corresponding power spectra from a simulation with $1024^3$ particles in a $1\textrm{Gpc}\,h^{-1}$ box. Our results represent an initial step toward deriving the redshift drift fluctuation power spectra from $N$-body simulations and establishing a methodology for the statistical analysis of the redshift drift effect using data from future large-scale surveys. However, further work is required to refine the approach and achieve an accurate modeling of the redshift drift fluctuation power spectra.