The thermal Sunyaev-Zel'dovich Signature of Baryons in the Local Universe

Abstract

Using cosmological hydrodynamical simulations, we investigate the prospects of the thermal Sunyaev-Zel'dovich (tSZ) effect to detect the missing baryons in the local universe. We find that at least 80% of the tSZ luminosity is generated in collapsed structures, and that $\sim$ 70% of the remaining diffuse tSZ luminosity (i.e., $\sim 15$% of the total) comes from overdense regions with ${\delta }_{gas}>$10, such as filaments and superclusters. The gas present in slightly overdense and underdense regions with ${\delta }_{gas}<10$, despite making up 50% of the total baryon budget, leaves very little tSZ signature: it gives rise to only $\sim$ 5% of the total tSZ luminosity. Thus, future Cosmic Microwave Background (CMB) observations will be sensitive to, at best, one half of the missing baryons, improving the current observational status, but still leaving one half unobserved. Since most of the tSZ is generated in haloes, we find a tight correlation between gas pressure and galaxy number density. This allows us to predict the CMB Comptonization from existing galaxy surveys and to forecast the tSZ effect from the local structures probed by the Two Micron All Sky Survey (2MASS) galaxy catalog.

4 pages, 3 figures, submitted to ApJ. Comments welcome

References in corpus (2)

• The Contribution of the Intergalactic Medium to Cosmic Microwave Background Anisotropies
• Millimetric observation of the SZ effect in the Corona Borealis supercluster

Cited by in corpus (9)

• The Santa Fe Light Cone Simulation Project: I. Confusion and the WHIM in Upcoming Sunyaev-Zel'dovich Effect Surveys
• The probability distribution function of the SZ power spectrum: an analytical approach
• The cosmic shallows I: interaction of CMB photons in extended galaxy halos
• Implementation of a Fourier Matched Filter in CMB Analyses. Application to ISW Studies
• The contribution of the kinematic Sunyaev-Zel'dovich Effect from the Warm Hot Intergalactic Medium to the Five-Year WMAP Data
• Missing baryons, bulk flows and the E-mode polarization of the Cosmic Microwave Background
• A galaxy overdensity at z=0.401 associated with an X-ray emitting structure of Warm-Hot Intergalactic Medium
• Estimating Power Spectrum of Sunyaev-Zeldovich Effect from the Cross-Correlation between WMAP and 2MASS
• Reconstructing the Thermal Sunyaev-Zel'dovich Effect in 3D