Soft Xray Emission from the WarmHot Intergalactic Medium

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 ke. V): ~ 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 Tree. SPH 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:

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 e. V Energy Resolution 4 e. V (FHWM) Angular Resolution 4. 9 arcmin Field of View 29. 5’ x 29. 5’ Features Selected deep pointings All-sky survey Guest observer program

Configuration and Detection Limits Instrument Astro-E 2 Constellation-X XEUS MBE A (cm 2) 35 3, 000 40, 000 200 ΩFOV 2. 9’x 2. 9’ 2. 5’x 2. 5’ 1 x 1 29. 5 x 29. 5 ΩPIXEL 0. 48’ x 0. 48’ 5’x 5’ 2”x 2” 4. 9 x 4. 9 R 100 400 500 150 RAΩFOV (cm 2 deg 2) 7 2, 083 5, 556 6439 EW (ev) 138. 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.