does the universe have a metal floor? matthew pieri the ohio state university, 1st november, 2007...

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




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

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0.01 ≤ ρ ρ ≤100

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T ∝ ρ α

Intergalactic Medium at High-zIntergalactic Medium at High-zIntergalactic Medium at High-zIntergalactic Medium at High-z

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T ~ 104 K

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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)

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

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Ao

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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

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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


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

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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

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nOVInHI

= 0.04 − 0.08

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nOVInHI

≤ 0.02


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


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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


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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


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


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

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ρ ρ ≤6

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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


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

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ρ ρ ~ 0.1

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ρ ρ ≈4

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)

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˙ ̇ 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

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˙ 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

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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

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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

Radius vs. Opening AngleRadius vs. Opening AngleRadius vs. Opening AngleRadius vs. Opening Angle

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


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

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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

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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


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

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ρ ρ

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Φρ = ′ N ′ ρ <ρ ′ N ′ ρ <ρ ,180

where N’where N’ρρ’<’<ρρ - - cumulative version cumulative version (densities below (densities below ρρ))


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


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

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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

does the universe have a metal floor? matthew pieri the ohio state university, 1st november, 2007...

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