MATTEO VIEL

STRUCTURE FORMATION

INAF and INFN Trieste

SISSA LECTURE #4 – March 14th 2011

OUTLINE: LECTURES

1. Structure formation: tools and the high redshift universe

2. The dark ages and the universe at 21cm

3. IGM cosmology at z=2=6

4. IGM astrophysics at z=2-6

5. Low redshift: gas and galaxies

6. Cosmological probes LCDM scenario

OUTLINE: LECTURE 4

Galactic winds and metal enrichment

The evolution of the UV background

The Warm-Hot Intergalactic Medium

GALACTIC

WINDS

Local galactic winds M82 optical and infra-red

Galactic winds –I

Local galactic winds M82 X-ray

Galactic winds –II

Flux

Temp.

Dens.

Log TempLog overdensity

Theory: Galactic winds

do they destroy the forest ?

Theuns, MV, et al, 2002, ApJ, 578, L5

Feedback effects: Galactic winds-IV

Line widths distribution

Column density distribution function

Metal enrichment CIV systems at z=3

Strong Feedback =1 ---- Role of the UV background

Soft background ---- Role of different feedback

e=1

e=0.1

Mori, Ferrara, Madau 2000; Rauch, Haehnelt, Steinmetz 1996; Schaye et al. 2003

e=0

Observations: the POD technique

Aguirre,Schaye, Theuns, 2002, ApJ, 576, 1Cowie & Songaila, 1998, Nature, 394, 44Pieri & Haehnelt, 2004, MNRAS, 347, 985

Pixel-by-pixel search using higher order transitions

Springel & Hernquist 2002,2003

Observations: the POD technique-II

Schaye et al., 2003, ApJ, 596, 768

NO SCATTER INTHE Z- relation

SCATTER INTHE Z- relation

Good fit to the median but not for the scatter

Observations: the POD technique-III

Schaye et al., 2003, ApJ, 596, 768

VARIANCE OF THE METALLICITYLognormal fit

When did the IGM become enriched – II ?

Adelberger et al. 2005

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

UV BACKGROUND

Ionizing background – I

Bolton, Haehnelt, MV, Springel, 2005, MNRAS, 357, 1178

With the fluctuating Gunn – Peterson approximation ~ 1/ -12

Photo

ioniz

ati

on

rate

Ionizing background-II

Bolton, Haehnelt, MV, Springel, 2005, MNRAS, 357, 1178

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

Summary

WHIM

WHIM - I

Fukugita, Hogan, Peebles, 1998, ApJ, 503, 518Cen & Ostriker 1999, ApJ, 514, 1L

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. - WHIM estimate. - Systematic effects. Joint emission+absorption analysis - Spatial distribution of WHIM and its bias

WHIM - II

To asses model (random+systematic) uncertainties To asses model (random+systematic) uncertainties we have used different techniques to simulate WHIM we have used different techniques to simulate WHIM

WHIM: model uncertainties – I

• Semi analytic model (Viel et al. 2003)• Hydro-dynamical model by Borgani• Hydro-dynamical model (Viel 2006)

Gadget-2 SPH code. Metallicity model: Z/ZGadget-2 SPH code. Metallicity model: Z/Zsunsun=min(0.2,0.025.=min(0.2,0.025.–1/3–1/3))

Simple sSimple star formationtar formation prescription. No Feedback. prescription. No Feedback.

Ions: OVI (KLL), OVIIKIons: OVI (KLL), OVIIK, OVII , OVII OVIII, CV, NeIX, MgXI FeXVII.OVIII, CV, NeIX, MgXI FeXVII.

Hybrid collisional ionization + (X+Hybrid collisional ionization + (X+UVUV) photoionization.) photoionization.

Independent spectra drawn by stacking outputs out to z=0.5 Independent spectra drawn by stacking outputs out to z=0.5 ((z=0.1)z=0.1)

= 0.7, m = 0.2457, b = 0.0463, h = 0.7, =

0.85L = 60 h -1 Mpc, , NDM = 4003, NGAS = 4003= 2.5 h -1 kpc

WHIM: model uncertainties – II

NOVII/z = 4–8NOVIII/z=0.6–1.3

Minimum flux (fluence) for detection

OVII K@z=0.46 EW=0.1 eV

OVII K @z=0.46 EW=0.072

OVII K@z=0.26 EW=0.1 eV

OVI KLL@z=0.26 EW=0.06 eV

Eulerian Hydro-simulation. Flat CDM L=25 Mpc/h. l=32.6 Kpc/h. Cen et al. 2003

Galaxy Light: Tully Catalog

Biasing hypothesis+

ADDING POWER

Gas properties

IGM distribution

CLOUDY

OVII distribution

WHIM as a mass tracer

OVII

NeIX

OVIII

OVII

OVIIINeX

NVI CVI

Nicastro et al 2002. PKS2155-304. 1 Absorber @ z~0

Nicastro et al 2005. Mark-421. 2 Absorbers @ z~0.011 and z~0.027

But see Kaastra et al. 2006 and Rasmussen et al 2006

WHIM: the observational state of the art

• Best bright background sources ? GRBs Best bright background sources ? GRBs

• Unambiguous WHIM at detection at z>0 ? YesUnambiguous WHIM at detection at z>0 ? Yes

• Measuring Measuring WHIMWHIM ? Yes. ? Yes. • Tracing Dark Matter (Tracing Dark Matter (mm)) ? ? NoNo

• WHIM spatial distribution ? Yes. EmissionWHIM spatial distribution ? Yes. Emission

..alternative observational strategies are also possible ..alternative observational strategies are also possible

Summary - WHIM

WHIM and feedback - II