1. STRUCTURE FORMATION MATTEO VIEL INAF and INFN Trieste
SISSA LECTURE #4 – March 14th 2011

2. OUTLINE: LECTURES
Structure formation: tools and the high redshift universe
The dark ages and the universe at 21cm
IGM cosmology at z=2=6
IGM astrophysics at z=2-6
Low redshift: gas and galaxies
6. Cosmological probes LCDM scenario

3. OUTLINE: LECTURE 4 Galactic winds and metal enrichment
The evolution of the UV background
The Warm-Hot Intergalactic Medium

4. GALACTIC
WINDS

5. Galactic winds –I Local galactic winds M82 X-ray
Local galactic winds M82 optical and infra-red

6. Galactic winds –II Theory: Galactic winds do they destroy the forest ?
Log overdensity
Log Temp
Flux
Temp.
Dens.
Theuns, MV, et al, 2002, ApJ, 578, L5

7. Feedback effects: Galactic winds-IV
Line widths distribution
Column density distribution function

8. Metal enrichment CIV systems at z=3
Strong Feedback e= Role of the UV background
Mori, Ferrara, Madau 2000;
Rauch, Haehnelt, Steinmetz 1996;
Schaye et al. 2003
Soft background ---- Role of different feedback
e=0
e=1
e=0.1

9. Observations: the POD technique
Aguirre,Schaye, Theuns, 2002, ApJ, 576, 1
Cowie & Songaila, 1998, Nature, 394, 44
Pieri & Haehnelt, 2004, MNRAS, 347, 985
Pixel-by-pixel search using higher order transitions

10. Springel & Hernquist 2002,2003

11. Observations: the POD technique-II
NO SCATTER IN
THE Z-r relation
SCATTER IN
THE Z-r relation
Good fit to the median but not for the scatter
Schaye et al., 2003, ApJ, 596, 768

12. Observations: the POD technique-III
VARIANCE OF THE METALLICITY
Lognormal fit
Schaye et al., 2003, ApJ, 596, 768

13. When did the IGM become enriched – II ?
Adelberger et al. 2005

14. GALAXY-IGM CONNECTION
- Early or late metal enrichment???? PopIII objects?? Where are the
metals? How far can they get?
- Search for galactic winds. No definitive proof of galactic winds
at high redshift. DEFINITIVE proof will be signatures of outflows
in QUASAR PAIRS (within 2yrs)?
- Lyman-break proximity effect? Is there still something odd?
radiative transfer effects?
- Better modelling of the ISM into cosmological hydro simulations
ISM-IGM connection

15. UV BACKGROUND

16. Ionizing background – I
t ~ 1/ G -12
With the fluctuating Gunn – Peterson approximation
Photoionization rate
Bolton, Haehnelt, MV, Springel, 2005, MNRAS, 357, 1178

17. Ionizing background-II
Bolton, Haehnelt, MV, Springel, 2005, MNRAS, 357, 1178

18. Summary Metal enrichment: Significant progress made on the
understanding of the IGM-galaxy connection but still:
No proofs of strong galactic winds at high redshfit
No clues of who is polluting the IGM and to what extent.
PopIII? Lyman-break galaxies?
the amplitude, shape of the (fluctuating?) UV background
is quite uncertain

19. WHIM

20. WHIM - I Cen & Ostriker 1999, ApJ, 514, 1L
Fukugita, Hogan, Peebles, 1998, ApJ, 503, 518

21. WHIM - II
Possibility of detecting the WHIM in absorption with EDGE (Explorer of Diffuse Emission and Gamma-ray burst Explosions) characterize its physical state, spatial clustering and estimate the baryon mass density of the WHIM.
- WHIM models and uncertainties.
- Probability of WHIM detections.
- WWHIM estimate.
- Systematic effects. Joint emission+absorption analysis
- Spatial distribution of WHIM and its bias

22. WHIM: model uncertainties – I
To asses model (random+systematic) uncertainties we have used different techniques to simulate WHIM

23. WHIM: model uncertainties – II
Semi analytic model (Viel et al. 2003)
Hydro-dynamical model by Borgani
Hydro-dynamical model (Viel 2006)
= 0.7, m = , b = , h = 0.7,  = 0.85
L = 60 h -1 Mpc, , NDM = 4003, NGAS = 4003, = 2.5 h -1 kpc
Gadget-2 SPH code. Metallicity model: Z/Zsun=min(0.2,0.025.r–1/3)
Simple star formation prescription. No Feedback.
Ions: OVI (KLL), OVIIKa, OVII Kb, OVIII, CV, NeIX, MgXI FeXVII.
Hybrid collisional ionization + (X+UV) photoionization.
Independent spectra drawn by stacking outputs out to z=0.5 (Dz=0.1)

27. Minimum flux (fluence) for detection
NOVII/Dz = 4–8
NOVIII/Dz=0.6–1.3

28. OVII
EW=0.1 eV
OVII
EW=0.072
OVII
OVI
EW=0.06 eV

29. WHIM as a mass tracer Galaxy Light: Tully Catalog Biasing hypothesis +
Eulerian Hydro-simulation. Flat LCDM
L=25 Mpc/h. l=32.6 Kpc/h. Cen et al. 2003
Biasing hypothesis +
ADDING POWER
IGM distribution
Gas properties
OVII distribution
CLOUDY

30. But see Kaastra et al. 2006 and Rasmussen et al 2006
WHIM: the observational state of the art
Nicastro et al PKS
1 z~0
Nicastro et al Mark-421.
2 z~0.011 and z~0.027
NeX
OVIII
OVII
OVII
NeIX
NVI
CVI
OVIII
But see Kaastra et al and Rasmussen et al 2006

31. Best bright background sources ? GRBs
Summary - WHIM
Best bright background sources ? GRBs
Unambiguous WHIM at detection at z>0 ? Yes
Measuring WWHIM ? Yes. e~20%
Tracing Dark Matter (Wm) ? No
WHIM spatial distribution ? Yes. Emission
..alternative observational strategies are also possible

33. WHIM and feedback - II