# Dissecting the thermal Sunyaev-Zeldovich-gravitational lensing cross-correlation with hydrodynamical simulations

Hojjati, A, McCarthy, IG, Harnois-Deraps, J, Ma, Y-Z, Waerbeke, LV, Hinshaw, G and Brun, AMCL (2014) Dissecting the thermal Sunyaev-Zeldovich-gravitational lensing cross-correlation with hydrodynamical simulations. Journal of Cosmology and Astroparticle Physics. ISSN 1475-7516 (Submitted)

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## Abstract

We use the cosmo-OWLS suite of cosmological hydrodynamical simulations, which includes different galactic feedback models, to predict the cross-correlation signal between weak gravitational lensing and the thermal Sunyaev-Zeldovich (tSZ) y-parameter. The predictions are compared to the recent detection reported by van Waerbeke and collaborators. The simulations reproduce the weak lensing-tSZ cross-correlation, ξyk (θ), well. The uncertainty arising from different possible feedback models appears to be important on small scales only ($\theta \lesssim 10$ arcmin), while the amplitude of the correlation on all scales is sensitive to cosmological parameters that control the growth rate of structure (such as $\sigma_8$, $\Omega_m$ and $\Omega_b$). This study confirms our previous claim (in Ma et al.) that a significant proportion of the signal originates from the diffuse gas component in low-mass ($M_{\rm{halo}} \lesssim 10^{14} M_{\odot}$) clusters as well as from the region beyond the virial radius. We estimate that approximately 20$\%$ of the detected signal comes from low-mass clusters, which corresponds to about 30$\%$ of the baryon density of the Universe. The simulations also suggest that more than half of the baryons in the Universe are in the form of diffuse gas outside halos ($\gtrsim 5$ times the virial radius) which is not hot or dense enough to produce a significant tSZ signal or be observed by X-ray experiments. Finally, we show that future high-resolution tSZ-lensing cross-correlation observations will serve as a powerful tool for discriminating between different galactic feedback models.

Item Type: Article astro-ph.CO; astro-ph.CO Q Science > QB Astronomy Astrophysics Research Institute IOP Publishing Author 12 Jun 2015 12:08 04 Sep 2021 14:34 https://researchonline.ljmu.ac.uk/id/eprint/695