Soft X-ray Emission from the Warm-Hot Intergalactic Medium
description
Transcript of Soft X-ray Emission from the Warm-Hot Intergalactic Medium
Taotao FangUC Berkeley
Collaborator: R. Croft, W. Sanders, J. Houck, R. Dave, N, Katz, D. Weinberg, L. Hernquist
Soft X-ray Emission from the Warm-Hot Intergalactic Medium
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
Enlarged Region of Area (A) and (B):
(A) (B)
Cross-correlation of metal emission with nearby galaxies
Auto-correlation:
In Partnership With:
MISSING BARYON EXPLORER
A mission to locate baryons…
…on the road to completing our picture of the Universe
Missing Baryon Explorer Energy Range 40 – 2000 eVEnergy Resolution 4 eV (FHWM)Angular Resolution 4.9 arcminField of View 29.5’ x 29.5’Features Selected deep pointings All-sky survey Guest observer program
Configuration and Detection Limits
Instrument Astro-E2 Constellation-X XEUS MBE
A (cm2) 35 3,000 40,000 200
ΩFOV 2.9’x2.9’ 2.5’x 2.5’ 1x1 29.5x29.5
ΩPIXEL 0.48’ x 0.48’ 5’x5’ 2”x2” 4.9x4.9
R 100 400 500 150
RAΩFOV
(cm2 deg2)7 2,083 5,556 6439
EW (ev) 138.0 8.0 4.9 4.5
MBE view of a 10º x 10º sky region
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.