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Does The Universe Have A Metal Does The Universe Have A Metal Floor?Floor?
Matthew Pieri
The Ohio State University, 1st November, 2007The Ohio State University, 1st November, 2007
Collaborators: Hugo Martel, Joop Schaye, Collaborators: Hugo Martel, Joop Schaye, Anthony Aguirre, Martin Haehnelt, Cédric Anthony Aguirre, Martin Haehnelt, Cédric
Grenon, Steeve PinsonneaultGrenon, Steeve Pinsonneault
Big question: Big question: How Widespread is Metal How Widespread is Metal Enrichment?Enrichment?
Why care?Why care?
Formation of galaxiesFormation of galaxies
Formation of Population III starsFormation of Population III stars
Properties of the Intergalactic MediumProperties of the Intergalactic Medium
Big question: Big question: How Widespread is Metal How Widespread is Metal Enrichment?Enrichment?
Why care?Why care?
Formation of galaxiesFormation of galaxies
Formation of Population III starsFormation of Population III stars
Properties of the Intergalactic MediumProperties of the Intergalactic Medium
OutlineOutlineOutlineOutline
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
To Earth
Heavy element absorption
Emission lines from the Quasar
Lyman limit
Hydrogen absorption due to galaxy
Quasar
Observed wavelength (Å)Lyman alpha forest
DLA
Illustration courtesy of John Webb
Filaments, pancakes & voids of structure that trace Filaments, pancakes & voids of structure that trace dark matterdark matter
Mostly moderately overdense, although can be Mostly moderately overdense, although can be
Mostly photoionized hydrogen since reionization Mostly photoionized hydrogen since reionization epochepoch
neutral to 1 part in 10neutral to 1 part in 1044
atat
From photoionization heating and adiabatic From photoionization heating and adiabatic coolingcooling
No in situ metal enrichment No in situ metal enrichment
Hence need for transport mechanismHence need for transport mechanism
OVI and CIV most prominent metal speciesOVI and CIV most prominent metal species
Filaments, pancakes & voids of structure that trace Filaments, pancakes & voids of structure that trace dark matterdark matter
Mostly moderately overdense, although can be Mostly moderately overdense, although can be
Mostly photoionized hydrogen since reionization Mostly photoionized hydrogen since reionization epochepoch
neutral to 1 part in 10neutral to 1 part in 1044
atat
From photoionization heating and adiabatic From photoionization heating and adiabatic coolingcooling
No in situ metal enrichment No in situ metal enrichment
Hence need for transport mechanismHence need for transport mechanism
OVI and CIV most prominent metal speciesOVI and CIV most prominent metal species
€
0.01 ≤ ρ ρ ≤100
€
T ∝ ρ α
Intergalactic Medium at High-zIntergalactic Medium at High-zIntergalactic Medium at High-zIntergalactic Medium at High-z
€
T ~ 104 K
€
ρ ρ ~ 1
Galaxy Formation and Evolution of Galaxy Formation and Evolution of the IGMthe IGM
Galaxy Galaxy formationformation
FeedbackFeedback
Gravitational Gravitational instabilityinstability
Energy dissipationEnergy dissipation
Radiative Radiative feedbackfeedback
OutflowsOutflows
IGMIGM GalaxiGalaxieses
HeatingHeating(Re)ionization(Re)ionization
HeatingHeatingCollisional IonizationCollisional IonizationKinetic energyKinetic energyMetal depositionMetal deposition
Where To Look For Widespread Where To Look For Widespread EnrichmentEnrichment
Where To Look For Widespread Where To Look For Widespread EnrichmentEnrichment
Low density regions (around mean density or Low density regions (around mean density or lower)lower)
Ionization species which are dominant thereIonization species which are dominant there
Regions far from galaxiesRegions far from galaxies
Locations requiredLocations required
Low density regions (around mean density or Low density regions (around mean density or lower)lower)
Ionization species which are dominant thereIonization species which are dominant there
Regions far from galaxiesRegions far from galaxies
Locations requiredLocations required
Line of sight to Quasar
Metal Outflow
Renyue Cen
Which Ionization Species to Look Which Ionization Species to Look ForFor
Which Ionization Species to Look Which Ionization Species to Look ForFor
Various ionization Various ionization species detectedspecies detected
OVIOVI
best tracer in the best tracer in the lowest density lowest density systems (voids)systems (voids)
CIV CIV
useful for moderate useful for moderate density systems density systems (filamentary (filamentary structures)structures)
Various ionization Various ionization species detectedspecies detected
OVIOVI
best tracer in the best tracer in the lowest density lowest density systems (voids)systems (voids)
CIV CIV
useful for moderate useful for moderate density systems density systems (filamentary (filamentary structures)structures)
Rauch, Haehnelt & Steinmetz (1997)
OutlineOutlineOutlineOutline
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
The Spectra IThe Spectra IThe Spectra IThe Spectra I
A synthetic LyA synthetic Ly forest in a QSO spectrum forest in a QSO spectrum
1D Gaussian Random field1D Gaussian Random field
Density power spectrum filtered for pressure Density power spectrum filtered for pressure effectseffects
PDF mapped to a lognormal - mimic non-linear PDF mapped to a lognormal - mimic non-linear structurestructure
Power law equation of statePower law equation of state
Noise, instrumental broadening and bulk absorption Noise, instrumental broadening and bulk absorption same as observedsame as observed
A synthetic LyA synthetic Ly forest in a QSO spectrum forest in a QSO spectrum
1D Gaussian Random field1D Gaussian Random field
Density power spectrum filtered for pressure Density power spectrum filtered for pressure effectseffects
PDF mapped to a lognormal - mimic non-linear PDF mapped to a lognormal - mimic non-linear structurestructure
Power law equation of statePower law equation of state
Noise, instrumental broadening and bulk absorption Noise, instrumental broadening and bulk absorption same as observedsame as observed
/Ang
The Spectra IIThe Spectra IIThe Spectra IIThe Spectra II
… … with an OVI forestwith an OVI forest
OVI (1032 ,1038 ) an excellent tracer of OVI (1032 ,1038 ) an excellent tracer of metals in voids metals in voids
BUT is found in the LyBUT is found in the Ly Forest in QSO spectra Forest in QSO spectra
… … with an OVI forestwith an OVI forest
OVI (1032 ,1038 ) an excellent tracer of OVI (1032 ,1038 ) an excellent tracer of metals in voids metals in voids
BUT is found in the LyBUT is found in the Ly Forest in QSO spectra Forest in QSO spectra
/Ang
€
Ao
€
Ao
A A LyLy forest – forest – and an OVI forestand an OVI forest
Binned byBinned by Ly and equivalent apparentand equivalent apparent OVI pixelspixels Median optical depths takenMedian optical depths taken Various techniques for minimising contamination Various techniques for minimising contamination
of OVI signalof OVI signal
zp zp
Pixel by Pixel SearchPixel by Pixel SearchPixel by Pixel SearchPixel by Pixel Search
/Ang
A A LyLy forest – forest – and an OVI forestand an OVI forest
Binned byBinned by Ly and equivalent apparentand equivalent apparent OVI pixelspixels Median optical depths takenMedian optical depths taken Various techniques for minimising contamination Various techniques for minimising contamination
of OVI signalof OVI signal Sensitive to weak absorption throughout the Sensitive to weak absorption throughout the
spectrumspectrum
zp zp
Pixel by Pixel SearchPixel by Pixel SearchPixel by Pixel SearchPixel by Pixel Search
/Ang
Overall Affect on SearchOverall Affect on SearchOverall Affect on SearchOverall Affect on Search
)log( Ly
€
log(Apparent τ OVI )
Real and Synthetic Spectra with Real and Synthetic Spectra with best best
Real and Synthetic Spectra with Real and Synthetic Spectra with best best
Spectra UsedSpectra Used
Q1122-165Q1122-165
z=2.0-2.3z=2.0-2.3
Q1442+293Q1442+293
z=2.5-2.6z=2.5-2.6
Q1107+485Q1107+485
z=2.7-3.0z=2.7-3.0
Q1422+231Q1422+231
z=3.2-3.5z=3.2-3.5
Spectra UsedSpectra Used
Q1122-165Q1122-165
z=2.0-2.3z=2.0-2.3
Q1442+293Q1442+293
z=2.5-2.6z=2.5-2.6
Q1107+485Q1107+485
z=2.7-3.0z=2.7-3.0
Q1422+231Q1422+231
z=3.2-3.5z=3.2-3.5
€
nOVI nHI
MP & Haehnelt (2004)MP & Haehnelt (2004)
Statistical Significance of OVI DetectionStatistical Significance of OVI DetectionStatistical Significance of OVI DetectionStatistical Significance of OVI Detection
22 test of agreement test of agreement between simulation between simulation and observationand observation
in three of the four in three of the four QSOs results QSOs results consistent with consistent with
for for Q1422Q1422
22 test of agreement test of agreement between simulation between simulation and observationand observation
in three of the four in three of the four QSOs results QSOs results consistent with consistent with
for for Q1422Q1422
€
nOVInHI
= 0.04 − 0.08
€
nOVInHI
≤ 0.02
MP & Haehnelt (2004)MP & Haehnelt (2004)
Statistical Significance of Low Density Statistical Significance of Low Density DetectionDetection
Statistical Significance of Low Density Statistical Significance of Low Density DetectionDetection
No OVI below No OVI below (95% (95% confidence)confidence)
Limit mainly Limit mainly contamination by contamination by Lyman linesLyman lines
No OVI below No OVI below (95% (95% confidence)confidence)
Limit mainly Limit mainly contamination by contamination by Lyman linesLyman lines
MP & Haehnelt (2004)MP & Haehnelt (2004)
€
ρ ρ ≈4
Volume Filling Factor of MetalsVolume Filling Factor of MetalsVolume Filling Factor of MetalsVolume Filling Factor of Metals
Fraction of universe Fraction of universe filled by overdensities filled by overdensities
and aboveand above
Provides fraction of Provides fraction of the universe that is the universe that is metal enrichedmetal enriched
Volume filling factor Volume filling factor 4% or more4% or more
Fraction of universe Fraction of universe filled by overdensities filled by overdensities
and aboveand above
Provides fraction of Provides fraction of the universe that is the universe that is metal enrichedmetal enriched
Volume filling factor Volume filling factor 4% or more4% or more
MP & Haehnelt (2004)MP & Haehnelt (2004)
€
n n ( )cut
Can We Do Better With CIV?Can We Do Better With CIV?Can We Do Better With CIV?Can We Do Better With CIV?
No LyNo Lyαα forest but lower forest but lower ττ
New limit - noise and continuum fittingNew limit - noise and continuum fitting
No LyNo Lyαα forest but lower forest but lower ττ
New limit - noise and continuum fittingNew limit - noise and continuum fitting
Spectra UsedSpectra Used
PKS2126-158PKS2126-158 z=2.6-3.2z=2.6-3.2
Q1422+231Q1422+231 z=2.9-3.5z=2.9-3.5
Q0055-269Q0055-269 Z=2.9-3.5Z=2.9-3.5
Spectra UsedSpectra Used
PKS2126-158PKS2126-158 z=2.6-3.2z=2.6-3.2
Q1422+231Q1422+231 z=2.9-3.5z=2.9-3.5
Q0055-269Q0055-269 Z=2.9-3.5Z=2.9-3.5
CIV Statistical SignificanceCIV Statistical SignificanceCIV Statistical SignificanceCIV Statistical Significance
We findWe find
No detection for No detection for (95% (95% confidence)confidence)
Volume Filling Factor Volume Filling Factor 1% or more1% or more
Schaye et al. (2003) Schaye et al. (2003)
CIV down to CIV down to
With large scatter With large scatter
VFF still poorly VFF still poorly constrainedconstrained
€
ρ ρ ≤6
€
ρ ρ ≈0.1
Nearby Lyman Break Galaxies and the IGMNearby Lyman Break Galaxies and the IGMNearby Lyman Break Galaxies and the IGMNearby Lyman Break Galaxies and the IGM
Adelberger et al. Adelberger et al. (2003, 2005)(2003, 2005)
Find strong CIV and Find strong CIV and close LBG are same close LBG are same systemssystems
X-correlation of X-correlation of log(Nlog(NCIVCIV)>12.5 and LBGs )>12.5 and LBGs similar to LBG similar to LBG autocorrelationautocorrelation
Claim Claim allall enrichment enrichment from superwinds at z ~ 3from superwinds at z ~ 3
What is the spatial distribution of What is the spatial distribution of metals that are seen with the pixel metals that are seen with the pixel search?search?
Two Samples of PixelsTwo Samples of PixelsTwo Samples of PixelsTwo Samples of Pixels
Line Of Sight
Marker pixels in LOSPixels in LOS within km/s
of marker pixels LBG
MP, Schaye & Aguirre (2006)MP, Schaye & Aguirre (2006)
Markers provided byMarkers provided byLBGsLBGsStrong CIV absorptionStrong CIV absorption
Strong CIV Absorption as a proxy Strong CIV Absorption as a proxy for Galaxiesfor Galaxies
Strong CIV Absorption as a proxy Strong CIV Absorption as a proxy for Galaxiesfor Galaxies
8% of pixels in “near” sample8% of pixels in “near” sample Nearest 30km/s discardedNearest 30km/s discarded Clear signal of excess enrichment close to strong Clear signal of excess enrichment close to strong
CIVCIV Most enrichment detected far from strong CIVMost enrichment detected far from strong CIV Scatter in sub-samples lower but not low enoughScatter in sub-samples lower but not low enough
8% of pixels in “near” sample8% of pixels in “near” sample Nearest 30km/s discardedNearest 30km/s discarded Clear signal of excess enrichment close to strong Clear signal of excess enrichment close to strong
CIVCIV Most enrichment detected far from strong CIVMost enrichment detected far from strong CIV Scatter in sub-samples lower but not low enoughScatter in sub-samples lower but not low enough
MP, Schaye & Aguirre (2006)MP, Schaye & Aguirre (2006)
Summary of ObservationsSummary of ObservationsSummary of ObservationsSummary of Observations
Consistent with full enrichment down toConsistent with full enrichment down to
Partial enrichment down to Partial enrichment down to
Volume filling factor > Volume filling factor > 4% 4%
Large scatter in the metallicity Large scatter in the metallicity
Increase in enrichment near galaxiesIncrease in enrichment near galaxies
BUT regions far from known galaxies (and most BUT regions far from known galaxies (and most of metals by volume) still show enrichmentof metals by volume) still show enrichment
Inclusion of known galaxy location lowers Inclusion of known galaxy location lowers scatterscatter
Consistent with full enrichment down toConsistent with full enrichment down to
Partial enrichment down to Partial enrichment down to
Volume filling factor > Volume filling factor > 4% 4%
Large scatter in the metallicity Large scatter in the metallicity
Increase in enrichment near galaxiesIncrease in enrichment near galaxies
BUT regions far from known galaxies (and most BUT regions far from known galaxies (and most of metals by volume) still show enrichmentof metals by volume) still show enrichment
Inclusion of known galaxy location lowers Inclusion of known galaxy location lowers scatterscatter
€
ρ ρ ~ 0.1
€
ρ ρ ≈4
OutlineOutlineOutlineOutline
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
Background: The Intergalactic MediumBackground: The Intergalactic Medium
Observations of the extent of enrichmentObservations of the extent of enrichment
Model for galactic outflowsModel for galactic outflows
Galactic OutflowsGalactic Outflows
Many simultaneous Type II supernovae (SNe II) Many simultaneous Type II supernovae (SNe II) in the starburst phasein the starburst phase
Coherent Extragalactic OutflowsCoherent Extragalactic Outflows
Outflows may be necessary to explain many Outflows may be necessary to explain many observations and solve many problems:observations and solve many problems:
• Metallicity of the IGMMetallicity of the IGM
• Entropy content of the IGMEntropy content of the IGM
• Abundance of Local Group dwarf Abundance of Local Group dwarf galaxiesgalaxies
• M/L ratio of dwarf galaxies M/L ratio of dwarf galaxies
• Overcooling problemOvercooling problem
• ……
Value of Anisotropic OutflowsValue of Anisotropic OutflowsValue of Anisotropic OutflowsValue of Anisotropic Outflows
Travel preferentially in to low-density Travel preferentially in to low-density regionsregions
Not require large volume filling factorsNot require large volume filling factors
Travel furtherTravel further
Provide a source of metallicity scatterProvide a source of metallicity scatter
Observations of Anisotropic Outflows
Near IR and Near IR and visible ACS-HST visible ACS-HST mosaic of M82 mosaic of M82 ((Gallagher, Mountain Gallagher, Mountain & Puxley)& Puxley)
H emission
Blue, star Blue, star forming forming regionregion
For well-formed For well-formed disks (Mac Low & disks (Mac Low & Ferrara, 1999)Ferrara, 1999)
Dark matter halo Dark matter halo (NFW, MIS)(NFW, MIS)
Gaseous diskGaseous disk
Simulations of Individual Objects I - Disk scale effectsSimulations of Individual Objects I - Disk scale effects
Better description Better description ofof
Larger scale Larger scale effect of many effect of many randomly randomly orientated disksorientated disks
Forming galaxies Forming galaxies in starburst phasein starburst phase
Off centre Off centre explosionsexplosionsBlueBlue: cold, dense : cold, dense gasgas
RedRed: hot gas : hot gas (outflow)(outflow)
Simulation of Individual Objects II - Halo scale effectsSimulation of Individual Objects II - Halo scale effects
Superposition of 3 intersecting plane-wave density perturbationsSuperposition of 3 intersecting plane-wave density perturbations
Galaxy at intersection of 2 filaments inside a cosmological pancakeGalaxy at intersection of 2 filaments inside a cosmological pancake
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
Analytical Model for Analytical Model for Anisotropic OutflowsAnisotropic Outflows
LSN
R(t)
MLSN
R(t)
M
e
e.g. Tegmark, Silk, & e.g. Tegmark, Silk, & Evrard (1993), Evrard (1993), Scannapieco & Scannapieco & Broadhurst (2001)Broadhurst (2001)
MP, Martel & Grenon MP, Martel & Grenon (2007)(2007)
The isotropic The isotropic casecase
An anisotropic An anisotropic casecase
Choice of Opening AngleChoice of Opening Angle
M82 M82 obs: obs:
~ 75~ 75oo
MacLow & MacLow & Ferrara Ferrara sims: sims:
~ 55~ 55oo
Martel & Shapiro Martel & Shapiro sims: sims:
~ 100~ 100oo
Hence, we treat opening angle as a free Hence, we treat opening angle as a free parameterparameter
3D Gaussian random field of volume (12 h3D Gaussian random field of volume (12 h-1-1 Mpc) Mpc)33
Filtered on 10 mass scales to reproduce halo Filtered on 10 mass scales to reproduce halo collapse on different scalescollapse on different scales
Unfiltered grid Unfiltered grid Filtered grids Filtered grids
++RR1 1 = 50.4 kpc= 50.4 kpc
MM1= 1= 7.6 x 107.6 x 1077 M M
RR10 10 =1.86 Mpc=1.86 Mpc
MM1010=3.8 x 10=3.8 x 101212 M M
For each filtered grid:For each filtered grid:
Find density peaksFind density peaks
Calculate direction of least resistanceCalculate direction of least resistance
Calculate collapse redshift (peak reaches Calculate collapse redshift (peak reaches and forms and forms halo)halo)
Check for mergers and unphysical halosCheck for mergers and unphysical halos
Monte Carlo SimulationMonte Carlo SimulationMonte Carlo SimulationMonte Carlo Simulation
Galaxy FormationGalaxy FormationGalaxy FormationGalaxy Formation
Halo gas heated to the THalo gas heated to the Tvirvir during collapse during collapse
Cools due to atomic line cooling Cools due to atomic line cooling
which is more efficient for metal enriched gaswhich is more efficient for metal enriched gas
Once gas is cooled star-formation beginsOnce gas is cooled star-formation begins
10% of gas turned into stars10% of gas turned into stars
Neglect life time of the most massive stars and SNe II Neglect life time of the most massive stars and SNe II beginbegin
Galactic outflow quenches star formationGalactic outflow quenches star formation
Burst length 50 MyrsBurst length 50 Myrs
10105151 ergs ergs released by each SN IIreleased by each SN II
1 SNII per 89.7 M1 SNII per 89.7 Msolsol of stars of stars
Outflow energy escapes galaxy with mass dependent Outflow energy escapes galaxy with mass dependent efficiencyefficiency
Halo gas heated to the THalo gas heated to the Tvirvir during collapse during collapse
Cools due to atomic line cooling Cools due to atomic line cooling
which is more efficient for metal enriched gaswhich is more efficient for metal enriched gas
Once gas is cooled star-formation beginsOnce gas is cooled star-formation begins
10% of gas turned into stars10% of gas turned into stars
Neglect life time of the most massive stars and SNe II Neglect life time of the most massive stars and SNe II beginbegin
Galactic outflow quenches star formationGalactic outflow quenches star formation
Burst length 50 MyrsBurst length 50 Myrs
10105151 ergs ergs released by each SN IIreleased by each SN II
1 SNII per 89.7 M1 SNII per 89.7 Msolsol of stars of stars
Outflow energy escapes galaxy with mass dependent Outflow energy escapes galaxy with mass dependent efficiencyefficiency
Density structure around a density peak on the halo Density structure around a density peak on the halo smoothing scale:smoothing scale:
peakpeak AxAx22 ByBy22
CzCz22 22DxyDxy
22ExzExz 22FyzFyz
Largest of Largest of ((AA’,’,BB’,’,CC’)’) Direction of least Direction of least resistanceresistance
Determine Determine AA, , BB, , CC, , DD, , EE, , FF by least-square fit. by least-square fit.
Rotate coordinate axes to Rotate coordinate axes to eliminate cross-terms eliminate cross-terms (D,E & F)(D,E & F)
((xx, , yy, , zz)) ((xx’, ’, yy’, ’, zz’) ’)
and and peak peak A’x’A’x’22 B’y’B’y’22 C’z’C’z’22
xx
z’z’
x’x’yy
zz
yy’’
Halo Smoothing ScaleHalo Smoothing Scale
The Direction of the OutflowThe Direction of the OutflowThe Direction of the OutflowThe Direction of the Outflow
Driving Driving pressurepressure
(energy (energy injection and injection and expansion)expansion)
(Energy deposition rate by (Energy deposition rate by Supernovae and dissipation Supernovae and dissipation rate by Compton drag) rate by Compton drag)
€
˙ ̇ R =8π G p − pext( )
ΩbH 2R−
3
R˙ R − HR( ) −
ΩH 2R
2−
GM
R2
Drag due to Drag due to sweeping up sweeping up IGMIGM
Gravitational Gravitational deceleration deceleration from the from the enclosed matter enclosed matter and the haloand the halo
€
˙ p =L
2π R3 1− cos α 2( )[ ]−
5 ˙ R p
R
€
L = LSN − Lcomp
The Expansion of the OutflowThe Expansion of the OutflowThe Expansion of the OutflowThe Expansion of the Outflow
Rate of Energy Deposition/DissipationRate of Energy Deposition/DissipationRate of Energy Deposition/DissipationRate of Energy Deposition/Dissipation
€
LSN = 2.86 fw f*
Ωb,0
Ω0
⎛
⎝ ⎜
⎞
⎠ ⎟
M
1Mù
⎛
⎝ ⎜
⎞
⎠ ⎟Lù
… … from IMF (Kropa 2001), energy per SN and from IMF (Kropa 2001), energy per SN and burst lengthburst length
ffww- energy escape - energy escape fractionfraction
ff**- star formation - star formation efficiency efficiency
€
Lcomp ∝ 1− cosα
2
⎛
⎝ ⎜
⎞
⎠ ⎟1+ z( )
4pR3
Cooling due to Compton drag against CMB Cooling due to Compton drag against CMB photons:photons:
Total rate of driving by SNe:Total rate of driving by SNe:
Equations solved numerically for radius, R, Equations solved numerically for radius, R, at each time-stepat each time-step
Largest outflow Largest outflow
= 180= 180oo
Halo Mass = 2.8 x Halo Mass = 2.8 x 10109 9 MM
Formed at z=8.1Formed at z=8.1
Example Isotropic OutflowExample Isotropic OutflowExample Isotropic OutflowExample Isotropic Outflow
MP, Martel & Grenon MP, Martel & Grenon (2007)(2007)
Two possibilities:Two possibilities:
1.1. Ram-pressure stripping (prevents Ram-pressure stripping (prevents galaxy formation) whengalaxy formation) when
2.2. Metal deposition: need to Metal deposition: need to recalculate cooling time (leads to recalculate cooling time (leads to earlier galaxy formation)earlier galaxy formation)
1.1. Calc based on volume of overlap Calc based on volume of overlap and metal content of outflows:and metal content of outflows:
Density Peaks Hits Before CollapseDensity Peaks Hits Before CollapseDensity Peaks Hits Before CollapseDensity Peaks Hits Before Collapse
Neighbouring
Collapsing peak
Source Halo
€
MZ =fesc f*
44.9
Ωb,0
Ω0
M2 M2 M of metals per SN of metals per SN and IMFand IMF
ffesc esc - mass escape - mass escape fractionfraction
€
l2
4R2
⎛
⎝ ⎜
⎞
⎠ ⎟Moυ o ≥ Mbυ esc
Our Simulation at End (z=2)Our Simulation at End (z=2)Our Simulation at End (z=2)Our Simulation at End (z=2)
Case of Case of = 40 = 40oo
Red wedges Red wedges
outflowsoutflows
Black circles Black circles
pre-collapse radius pre-collapse radius (smoothing scale) of (smoothing scale) of halos with galaxieshalos with galaxies
Galaxies in a Galaxies in a common filament common filament produce aligned produce aligned outflowsoutflows
MP, Martel & Grenon MP, Martel & Grenon (2007)(2007)
Volume Filling Factor StatisticsVolume Filling Factor StatisticsVolume Filling Factor StatisticsVolume Filling Factor Statistics
N - Total # of grid N - Total # of grid pointspoints
NNρρ - # of grid points - # of grid points at density at density ρρ
N’N’ρρ - # of enriched - # of enriched grid points at grid points at density density ρρ
- Gas - Gas overdensityoverdensity
€
ρ ρ
€
Φρ = ′ N ′ ρ <ρ ′ N ′ ρ <ρ ,180
where N’where N’ρρ’<’<ρρ - - cumulative version cumulative version (densities below (densities below ρρ))
MP, Martel & Grenon MP, Martel & Grenon (2007)(2007)
Impact of Reionization on Impact of Reionization on Enrichment of IGMEnrichment of IGM
Impact of Reionization on Impact of Reionization on Enrichment of IGMEnrichment of IGM
Remember that observations of 4% volume filling factor
Cumulative
Volume Filling Factor
F O C
MP & Martel MP & Martel (2007)(2007)
Impact on Enriching GalaxiesImpact on Enriching GalaxiesImpact on Enriching GalaxiesImpact on Enriching Galaxies
F O C
Volume Filling Factor
MP & Martel MP & Martel (2007)(2007)
ConclusionsConclusionsConclusionsConclusionsObservations consistent with Observations consistent with
Full enrichment down toFull enrichment down to
Partial enrichment down to Partial enrichment down to
Volume filling factor of metal enrichment > Volume filling factor of metal enrichment > 4%4%
Large unexplained scatter in metallicityLarge unexplained scatter in metallicity
More enrichment near known galaxies but still clear More enrichment near known galaxies but still clear signal of metals farsignal of metals far
Anisotropic outflows due to large scale structuresAnisotropic outflows due to large scale structures
Motivated by observations and simulationsMotivated by observations and simulations
Travel furtherTravel further into low-density regions, away from into low-density regions, away from filaments and sheets of structurefilaments and sheets of structure
With With in in dramatic dramatic in enrichment of high density in enrichment of high density systemssystems
Can enrich 10% more of the underdense Universe and 40% Can enrich 10% more of the underdense Universe and 40% more of Universe belowmore of Universe below
The extent of enrichment is sensitive to epoch of The extent of enrichment is sensitive to epoch of reionizationreionization
€
ρ ρ =0.1
€
ρ ρ ≈4
€
ρ ρ ~ 0.1
Future WorkFuture WorkFuture WorkFuture Work
Switch to N-bodySwitch to N-body
Produce fake spectra and compare with Produce fake spectra and compare with observationsobservations
Consider impact of reionization on PopIII Consider impact of reionization on PopIII star formation at z<5star formation at z<5
More sophisticated models of reionizationMore sophisticated models of reionization
SimulationsSimulationsAnalysis of dataAnalysis of data
Extent of Extent of enrichmenenrichmen
t?t?
More Answers!More Answers!
N-bodyN-body
AnalyticAnalytic
OVI Near to and Far from Strong CIVOVI Near to and Far from Strong CIVOVI Near to and Far from Strong CIVOVI Near to and Far from Strong CIV
Again excess enrichment close to strong CIVAgain excess enrichment close to strong CIV
Little or no evidence for OVI in far sampleLittle or no evidence for OVI in far sample
Mostly likely since OVI too weak to detectMostly likely since OVI too weak to detect
Better examples of OVI detection at lower zBetter examples of OVI detection at lower z
Again excess enrichment close to strong CIVAgain excess enrichment close to strong CIV
Little or no evidence for OVI in far sampleLittle or no evidence for OVI in far sample
Mostly likely since OVI too weak to detectMostly likely since OVI too weak to detect
Better examples of OVI detection at lower zBetter examples of OVI detection at lower z