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

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MATTEO VIEL


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slide1

STRUCTURE FORMATION

MATTEO VIEL

INAF and INFN Trieste

SISSA LECTURE #4 – March 14th 2011

slide2

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
  • 5. Low redshift: gas and galaxies
  • 6. Cosmological probes LCDM scenario
slide3

OUTLINE: LECTURE 4

Galactic winds and metal enrichment

The evolution of the UV background

The Warm-Hot Intergalactic Medium

slide5

Galactic winds –I

Local galactic winds M82 X-ray

Local galactic winds M82 optical and infra-red

slide6

Theory: Galactic winds

do they destroy the forest ?

Galactic winds –II

Log overdensity

Log Temp

Flux

Temp.

Dens.

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

slide7

Feedback effects: Galactic winds-IV

Line widths distribution

Column density distribution function

slide8

Metal enrichment CIV systems at z=3

Strong Feedback e=1 ---- 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

slide9

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

slide11

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

slide12

Observations: the POD technique-III

VARIANCE OF THE METALLICITY

Lognormal fit

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

slide14

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

slide16

Ionizing background – I

t ~ 1/ G-12

With the fluctuating Gunn – Peterson approximation

Photoionization rate

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

slide17

Ionizing background-II

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

slide18

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
slide20

WHIM - I

Cen & Ostriker 1999, ApJ, 514, 1L

Fukugita, Hogan, Peebles, 1998, ApJ, 503, 518

slide21

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.

- WWHIMestimate.

- Systematic effects. Joint emission+absorption analysis

- Spatial distribution of WHIM and its bias

slide22

WHIM: model uncertainties – I

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

slide23

= 0.7, m = 0.2457, b = 0.0463, h = 0.7, = 0.85

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

WHIM: model uncertainties – II

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

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)

slide27

Minimum flux (fluence) for detection

NOVII/Dz = 4–8

NOVIII/Dz=0.6–1.3

slide28

OVII Ka @z=0.26

EW=0.1 eV

OVII Ka @z=0.46

EW=0.1 eV

OVII Kb @z=0.46

EW=0.072

OVI KLL@z=0.26

EW=0.06 eV

slide29

WHIM as a mass tracer

Eulerian Hydro-simulation. Flat LCDM

L=25 Mpc/h. l=32.6 Kpc/h. Cen et al. 2003

GalaxyLight: TullyCatalog

Biasing hypothesis

+

ADDING POWER

IGM distribution

Gas properties

OVII distribution

CLOUDY

slide30

WHIM: the observational state of the art

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

NeX

OVIII

OVII

OVII

NeIX

NVI

CVI

OVIII

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

slide31

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