Multiwavelength cross-correlation analysis of the simulated cosmic web

Abstract

We used magnetohydrodynamical cosmological simulations to investigate the cross-correlation between different observables (i.e. X-ray emission, Sunyaev–Zeldovich (SZ) signal at 21 cm, H i temperature decrement, diffuse synchrotron emission, and Faraday Rotation) as a probe of the diffuse matter distribution in the cosmic web. We adopt a uniform and simplistic approach to produce synthetic observations at various wavelengths, and we compare the detection chances of different combinations of observables correlated with each other and with the underlying galaxy distribution in the volume. With presently available surveys of galaxies and existing instruments, the best chances to detect the diffuse gas in the cosmic web outside of haloes is by cross-correlating the distribution of galaxies with SZ observations. We also find that the cross-correlation between the galaxy network and the radio emission or the Faraday Rotation can already be used to limit the amplitude of extragalactic magnetic fields, well outside of the cluster volume usually explored by existing radio observations, and to probe the origin of cosmic magnetism with the future generation of radio surveys.

Discovery of magnetic fields along stacked cosmic filaments as revealed by radio and X-ray emission

“…We also repeated the above procedure for a different set of simulations, described in Gheller & Vazza (2020). These simulations are lower resolution (83 kpc pixel size, 85 3 Mpc 3 total volume) but include different physical scenarios such as : an astrophysical scenario with B injected by AGNs and star-forming regions, following the cosmic star formation history; a primordial model with a stronger primordial magnetic field of 1 nG; and a dynamo model in which at run-time intracluster medium-like amplification of magnetic fields is assumed, included within filaments.…”

Simulations and observational tests of primordial magnetic fields from Cosmic Microwave Background constraints

“…Vernstrom et al (2017) reported no significant detection of cross-correlation between galaxies and radio emission on ≥20 arcmin scales, and used this information to derive upper limits on the typical magnetization of filaments of the cosmic web. In Gheller & Vazza (2020), we introduced a procedure to simulate the crosscorrelation between the diffuse radio emission at 180 MHz and the projected galaxy distribution in the simulation. In particular, we set the threshold of projected DM density to ρ th = 6 × 10 −29 g cm −3 in order to produce a number of galaxies (i.e.…”

“…Following Gheller & Vazza (2020), the normalized correlation matrix C between 2D N × M pixels images A and B is evaluated through…”

Properties of gas phases around cosmic filaments atz= 0 in the IllustrisTNG simulation

“…Martizzi et al (2019) analyse the gas content and separated gas into different phases of the various structures of the cosmic web at different redshifts of the IllustrisTNG simulation (Nelson et al 2019). More recently, Gheller & Vazza (2020) show that one of the most promising tracers of gas in the diffuse warm-hot intergalactic medium (WHIM) around filaments is the Sunyaev-Zel'dovich (SZ) effect, thanks to its linear dependence on gas pressure.…”