Warm-hot intergalactic medium contribution to baryonic matter

Abstract

Hydrodynamical simulations indicate that substantial fraction of baryons in the Universe remains in a diffuse component - Warm-Hot Intergalactic Medium (WHIM). To determine physical properties (spatial distribution, temperature and density) of the WHIM, spatial structure of the soft extended X-ray emission surrounding field galaxies is carefully investigated using the XMM-Newton EPIC/MOS observations. Angular correlations between the galaxy distribution and the soft X-ray background extending over several arcmin are determined. The correlations at large scales result from the clustering of galaxies. At small scales (below ~2 arcmin) the excess of the soft flux is interpreted as the genuine emission from halos of the WHIM surrounding individual galaxies. Bulk parameters of the average WHIM halos associated with galaxies in the sample are estimated. Typical halo has a characteristic radius of ~0.3 Mpc and a mass of 4 - 7 x 10^11 M_sun. The average density of the WHIM in the local universe amounts to 7 - 11 x 10^{-32} g cm^{-3} (Omega_WHIM = 0.7 - 1.2 %). Observations of the X-ray WHIM emission are in good agreement with the numerical simulations, but accuracy of the observational material is insufficient to constrain the theory of WHIM. A series of deep observations of a moderately numerous sample of low redshift galaxies with high resolution instruments of Chandra would significantly improve our estimates of the WHIM parameters.

9 pages, 6 figures

References in corpus (16)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Where are the Baryons?
• Baryons in the Warm-Hot Intergalactic Medium
• The Chandra Deep Field-North Survey. XIII. 2 Ms Point-Source Catalogs
• The 2dF Galaxy Redshift Survey: Spectral Types and Luminosity Functions
• Intervening O VI Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir
• The baryon content of the Universe
• The APM Galaxy Survey III: An Analysis of Systematic Errors in the Angular Correlation Function and Cosmological Implications
• Hydrodynamic Simulation of the Cosmological X-ray Background
• XMM-Newton EPIC background modeling for extended sources
• The baryonic mass function of galaxies
• The X-ray surface brightness distribution from diffuse gas
• X-Ray Constraints on the Warm_hot Intergalactic Medium
• Missing baryons and the soft X-ray background
• XMM-Newton Data Processing for Faint Diffuse Emission: Proton Flares, Exposure Maps and Report on EPIC MOS1 Bright CCDs Contamination
• Measuring Feedback Using the Intergalactic Medium State and Evolution Inferred from the Soft X-ray Background

Cited by in corpus (12)

• The Baryon Census in a Multiphase Intergalactic Medium: 30% of the Baryons May Still Be Missing
• Hot gas halos around disk galaxies: Confronting cosmological simulations with observations
• Resolving the unresolved cosmic X-ray background in the Chandra Deep Fields
• Where Do Galaxies End?
• The nature of the unresolved extragalactic soft CXB
• First measurement of the bulk flow of nearby galaxies using the cosmic microwave background
• The Cross-correlation of KSZ Effect and 21 cm Intensity Mapping with Tidal Reconstruction
• A galaxy overdensity at z=0.401 associated with an X-ray emitting structure of Warm-Hot Intergalactic Medium
• The contribution of the Warm-Hot Intergalactic Medium to the CMB anisotropies via the Sunyaev-Zeldovich effect
• Constituents of the soft X-ray background
• Lensing and the Warm Hot Intergalactic Medium
• The signature of the Warm Hot Intergalactic Medium in WMAP and the forthcoming PLANCK data