Kavli Affiliate: George Efstathiou
| Summary:
We study the implications of relaxing the requirement for ultralight axions to account for all dark matter in the Universe by examining mixed dark matter (MDM) cosmologies with axion fractions $f leq 0.3$ within the fuzzy dark matter (FDM) window $10^-25$ eV $lesssim m lesssim 10^-23$ eV. Our simulations, using a new MDM gravity solver implemented in AxiREPO, capture wave dynamics across various scales with high accuracy down to redshifts $zapprox 1$. We identify halos with Rockstar using the CDM component and find good agreement of inferred halo mass functions (HMFs) and concentration-mass relations with theoretical models across redshifts $z=1-10$. This justifies our halo finder approach a posteriori as well as the assumptions underlying the MDM halo model AxionHMcode. Using the inferred axion halo mass-cold halo mass relation $M_texta(M_textc)$ and calibrating a generalised smoothing parameter $α$ to our MDM simulations, we present a new version of AxionHMcode. The code exhibits excellent agreement with simulations on scales $k< 20 h$ cMpc$^-1$ at redshifts $z=1-3.5$ for $fleq 0.1$ around the fiducial axion mass $m = 10^-24.5$ eV $ = 3.16times 10^-25$ eV, with maximum deviations remaining below 10%. For axion fractions $fleq 0.3$, the model maintains accuracy with deviations under 20% at redshifts $zapprox 1$ and scales $k< 10 h$ cMpc$^-1$, though deviations can reach up to 30% for higher redshifts when $f=0.3$. Reducing the run-time for a single evaluation of AxionHMcode to below $1$ minute, these results highlight the potential of AxionHMcode to provide a robust framework for parameter sampling across MDM cosmologies in Bayesian constraint and forecast analyses.
| Search Query: arXiv Query: search_query=au:”Fialkov Anastasia”&id_list=&start=0&max_results=10
Read More