Simulated catalogs and maps of radio galaxies at millimeter wavelengths in Websky

TL;DR

This paper introduces simulated millimeter-wavelength maps and catalogs of radio galaxies based on the Websky simulation, accurately modeling their properties and correlations with other large-scale structure components for cosmological analyses.

Contribution

It presents a new framework for generating realistic radio galaxy samples from any halo catalog, integrating astrophysical and empirical models to match observed data.

Findings

Simulated radio galaxy counts match observations from Planck, ALMA, SPT, and ACT.

The model accurately reproduces spectral and polarization properties of radio galaxies.

Predictions for cross-correlations with CIB, tSZ, and CMB lensing maps are provided.

Abstract

We present simulated millimeter-wavelength maps and catalogs of radio galaxies across the full sky that trace the nonlinear clustering and evolution of dark matter halos from the Websky simulation at $z<4.6$ and $M_{\rm halo}>10^{12} M_{\odot}/h$, and the accompanying framework for generating a new sample of radio galaxies from any halo catalog of positions, redshifts, and masses. Object fluxes are generated using a hybrid approach that combines (1) existing astrophysical halo models of radio galaxies from the literature to determine the positions and rank-ordering of the observed fluxes with (2) empirical models from the literature based on fits to the observed distribution of flux densities and (3) spectral indices drawn from an empirically-calibrated frequency-dependent distribution. The resulting population of radio galaxies is in excellent agreement with the number counts, polarization fractions, and distribution of spectral slopes from the data from observations at millimeter wavelengths from 20-200~GHz, including \emph{Planck}, ALMA, SPT, and ACT. Since the radio galaxies are correlated with the existing cosmic infrared background (CIB), Compton-$y$ (tSZ), and CMB lensing maps from Websky, our model makes new predictions for the cross-correlation power spectra and stacked profiles of radio galaxies and these other components. These simulations will be important for unbiased analysis of a wide variety of observables that are correlated with large-scale structure, such as gravitational lensing and SZ clusters.