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Soft X-ray Emission from the Warm-Hot Intergalactic Medium. Taotao Fang UC Berkeley. Collaborator: R. Croft, W. Sanders, J. Houck, R. Dave, N, Katz, D. Weinberg, L. Hernquist. Baryon Phase Diagram:. Dave et al. (2001), Croft et al. (2001). Cosmic X-ray Background.
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Soft X-ray Emission from the Warm-Hot Intergalactic Medium Taotao Fang UC Berkeley Collaborator: R. Croft, W. Sanders, J. Houck, R. Dave, N, Katz, D. Weinberg, L. Hernquist
Baryon Phase Diagram: Dave et al. (2001), Croft et al. (2001)
Cosmic X-ray Background • Total Cosmic X-ray background (0.5 - 2 keV): ~ 6. - 8.10-12 ergs cm-2 s-1 deg-2 • Contribution from discrete sources: 74 - 94 % (Mushotzky et al. 2000) • Contribution from WHIM: likely ~ 5% (simulations from Croft et al. 2000, Phillips et al. 2001) • Metal line emission account for a significant portion of WHIM emission!
Simulating X-ray emission • Parallel TreeSPH simulation by Dave, Katz, Weinberg & Hernquist (see Dave et al. 2001, Croft et al. 2001 for details). • CDM with a cosmological constant • = 0.6, m= 0.4 • b= 0.02 h -2 • The simulation volume: a cube of side-length 50 h-1 Mpc • The spatial resolution is 7 h-1 kpc • Density-depended metallicity
MISSING BARYON EXPLORER A mission to locate baryons… …on the road to completing our picture of the Universe In Partnership With: Missing Baryon Explorer Energy Range 40 – 2000 eV Energy Resolution 4 eV (FHWM) Angular Resolution 4.9 arcmin Field of View 29.5’ x 29.5’ Features Selected deep pointings All-sky survey Guest observer program
MBE sky coverage: This plot shows the fraction of the sky probed by MBE with at least one detectable emission line.
Summary • Cosmological simulations: quantitative predictions of the physical properties of the WHIM gas and its observational signatures. • X-ray emission: mapping 3-D distribution of the WHIM gas. By combining imaging/spectroscopy measurement, X-ray emission shall provide direct evidence of the WHIM gas. • Cross-correlation with nearby galaxies: X-ray emission lines show strong cross-correlation with nearby large scale structure. Angular correlation: WHIM gas tends to cluster strongly at small angle. • Future prospective: high spatial/spectral resolution X-ray telescopes.