MATTEO VIEL
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Transcript of MATTEO VIEL
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