Neutral Gas Reservoirs Neutral Gas Reservoirs from z=0 to z ~ 5 from z=0 to z ~ 5

Neutral Gas Reservoirs Neutral Gas Reservoirs from z=0 to z ~ 5 from z=0 to z ~ 5

Art WolfeArt Wolfe Art WolfeArt Wolfe

Marc Rafelski: UCSDMarcel Neeleman: UCSDMichele Fumagali: UCSCJ. Xavier Prochaska: UCSCHsiao-Wen Chen: U. Chicago

Marc Rafelski: UCSDMarcel Neeleman: UCSDMichele Fumagali: UCSCJ. Xavier Prochaska: UCSCHsiao-Wen Chen: U. Chicago

DLAS are

•Definition of Damped LySystem (DLA): N(HI)≥ 21020 cm-2

•Distinguishing characteristics of DLAs : (1) Gas is Neutral (2) Metallicity is low: [M/H]=-1.3 (3) Molecular fraction is low:fH2~10-5

•DLAs cover 1/3 of the sky at z=[2.5,3.5]•DLAs dominate the neutral gas content of the Universe at z < 5

•Definition of Damped LySystem (DLA): N(HI)≥ 21020 cm-2

•Distinguishing characteristics of DLAs : (1) Gas is Neutral (2) Metallicity is low: [M/H]=-1.3 (3) Molecular fraction is low:fH2~10-5

•DLAs cover 1/3 of the sky at z=[2.5,3.5]•DLAs dominate the neutral gas content of the Universe at z < 5

Si IIFe II

Damped LyDamped Ly Absorption Systems Absorption SystemsDamped LyDamped Ly Absorption Systems Absorption Systems

Comoving HI mass density from Damped Lyα SystemsComoving HI mass density from Damped Lyα Systems

ρρ**(z=0)(z=0)

ρρ**(z=0)(z=0) RReepplleenniisshhmmeenntt ooff HH II rreeqquuiirreedd

Predicted Time Evolution of DLAsPredicted Time Evolution of DLAs (Faucher-Giguere & Keres 2011)(Faucher-Giguere & Keres 2011)

How are DLAs Related toHow are DLAs Related toGalaxies?Galaxies?

•Do DLA metallicities resemble those ofDo DLA metallicities resemble those of known stellar populations?known stellar populations?

•Size, Mass of Galaxies Hosting DLAs?Size, Mass of Galaxies Hosting DLAs?

•Relationship Between Absorbing Gas andRelationship Between Absorbing Gas and Known Star-Forming Galaxies, i.e. LBGs?Known Star-Forming Galaxies, i.e. LBGs?

Keck ESI Survey for DLAs at zKeck ESI Survey for DLAs at zabsabs> 4> 4

(Rafelski, Wolfe, & Prochaska 2011)(Rafelski, Wolfe, & Prochaska 2011)Keck ESI Survey for DLAs at zKeck ESI Survey for DLAs at zabsabs> 4> 4

(Rafelski, Wolfe, & Prochaska 2011)(Rafelski, Wolfe, & Prochaska 2011)

ESI Survey for ESI Survey for

high-z DLAshigh-z DLAs

• 26 quasar spectra26 quasar spectra

• 34 DLAs34 DLAs

• 30 in which z > 430 in which z > 4

Metal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest z

z=5.179z=5.179 z=4.820z=4.820 z=4.797z=4.797

[M/H] from S II and Si II, and Ly[M/H] from S II and Si II, and Ly[M/H] from S II and Si II, and Ly[M/H] from S II and Si II, and Ly

SIISII

SiISiIII

SIISII SiIISiII

SiIISiII

Metal Abundances and <Z/ZMetal Abundances and <Z/Z> versus redshift (2004 sample)> versus redshift (2004 sample)Metal Abundances and <Z/ZMetal Abundances and <Z/Z> versus redshift (2004 sample)> versus redshift (2004 sample)

<Z/Z<Z/Z>>

2004 sample + new ESI DLAs 2004 sample + new ESI DLAs

Metal Abundance versus look-back timeMetal Abundance versus look-back time

Comparison betweenComparison between

Metallicity distributionsMetallicity distributions

of DLAs with z=2-3of DLAs with z=2-3

and Galaxy stellarand Galaxy stellar

populationspopulations

Pettini (2006)Pettini (2006)

Comparison between halo stars and z>4 DLAsComparison between halo stars and z>4 DLAs

halo starshalo stars

z>4 DLAsz>4 DLAs

ALMA Search for [C II] 158 μm Emission from DLAsALMA Search for [C II] 158 μm Emission from DLAs

(Wolfe, Neeleman, Fumagali, Prochaska (Wolfe, Neeleman, Fumagali, Prochaska et al. et al. 2011)2011)

ALMA Search for [C II] 158 μm Emission from DLAsALMA Search for [C II] 158 μm Emission from DLAs

(Wolfe, Neeleman, Fumagali, Prochaska (Wolfe, Neeleman, Fumagali, Prochaska et al. et al. 2011)2011)

158 μm emission from the Galaxy (Bennet 158 μm emission from the Galaxy (Bennet etal.etal. 1994) 1994)

[C II] 158 μm contours superposed on 6.8 μm image[C II] 158 μm contours superposed on 6.8 μm image

Obtaining Cooling Rates from C II* AbsorptionObtaining Cooling Rates from C II* Absorption

• [C II] 158 micron transition dominates cooling of neutral gas in Galaxy ISM

• Spontaneous emission rate per atom lc=n[CII] obtained from strength of 1335.7 absorption and Lyman alpha absorption

• Thermal balance condition lc= pe

gives heating rate per atom for

cold neutral-medium (CNM)

2121)IH(*)IIC(

][ ~ Ahn NN

IIC ν 2121)IH(*)IIC(

][ ~ Ahn NN

IIC νlc =

Metal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest zMetal-line velocity profiles for 3 DLAs with highest z

z=5.179z=5.179 z=4.820z=4.820 z=4.797z=4.797

Bimodal Distribution of Cooling Rates Bimodal Distribution of Cooling Rates llcc

H I Contours on 158 μm image of simulated galaxies atH I Contours on 158 μm image of simulated galaxies at z=2.3 (Fumagali z=2.3 (Fumagali etal. etal. 2010)2010)

MMhh=6×10=6×101111MM

SFR=100 MSFR=100 Myy-1-1

SSνν=4 mJy=4 mJy

MMhh=2×10=2×101111MM

SFR=7 MSFR=7 Myy-1-1

SSνν =0.8 mJy =0.8 mJy

Alma 3-σ Sensitivity for Detecting 158 μm Emission vs zAlma 3-σ Sensitivity for Detecting 158 μm Emission vs z

Search for low surface-brightness emission fromSearch for low surface-brightness emission from star-forming gas surrounding LBG coresstar-forming gas surrounding LBG cores(Rafelski, Wolfe, & Chen 2011)(Rafelski, Wolfe, & Chen 2011)

Search for low surface-brightness emission fromSearch for low surface-brightness emission from star-forming gas surrounding LBG coresstar-forming gas surrounding LBG cores(Rafelski, Wolfe, & Chen 2011)(Rafelski, Wolfe, & Chen 2011)

Search for low surface-brightness emission fromSearch for low surface-brightness emission from star-forming gas surrounding LBG coresstar-forming gas surrounding LBG cores(Rafelski, Wolfe, & Chen 2011)(Rafelski, Wolfe, & Chen 2011)

Search for low surface-brightness emission fromSearch for low surface-brightness emission from star-forming gas surrounding LBG coresstar-forming gas surrounding LBG cores(Rafelski, Wolfe, & Chen 2011)(Rafelski, Wolfe, & Chen 2011)

•Test Kennicutt-Schmidt law for star formationTest Kennicutt-Schmidt law for star formation

in the outskirts of LBGsin the outskirts of LBGs

ΣΣSFRSFR((NN)=K)=Kkennkenn((NN//NNcc))β β ; β=1.4 ; β=1.4

•Make use of evidence for star formation in Make use of evidence for star formation in atomic-dominated gas situated in the outeratomic-dominated gas situated in the outer regions of nearby galaxies.regions of nearby galaxies.

Star Formation in Atomic-Dominated GasStar Formation in Atomic-Dominated Gas

M83:M83:H I ContoursH I Contourssuperposed onsuperposed onGalex FUV imageGalex FUV image(Biegel (Biegel etal.etal. 2010) 2010)

UDF Sample of compact, symmetric LGBsUDF Sample of compact, symmetric LGBs

Median stack of 48 compact, symmetric z~3 LBGsin V band UDF image

Median stack of 48 compact, symmetric z~3 LBGsin V band UDF image

Surface-brightness Profile of Stacked ImageSurface-brightness Profile of Stacked ImageSurface-brightness Profile of Stacked ImageSurface-brightness Profile of Stacked Image

Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas

•Differential:Differential:•Differential:Differential: ++ +…+…

Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas

•Differential:Differential:•Differential:Differential: ++ +…+…

Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I GasComoving SFR Density Predicted for H I Gas

•Differential:Differential:•Differential:Differential: ++ +…+…

•Transform from Transform from N N to intensityto intensity•Transform from Transform from N N to intensityto intensity

Predicted Predicted Surface Brightness vs comoving SFR densitySurface Brightness vs comoving SFR density

Theory Confronts ObservationTheory Confronts Observation

Kennicutt-Schmidt Law for Atomic-DominatedKennicutt-Schmidt Law for Atomic-Dominated Gas at high redshiftGas at high redshift

K-S laws predicted by simulations (Gnedin & Kravtsov 2009)K-S laws predicted by simulations (Gnedin & Kravtsov 2009)K-S laws predicted by simulations (Gnedin & Kravtsov 2009)K-S laws predicted by simulations (Gnedin & Kravtsov 2009)

Comparison between outskirts of LBGs and of local galaxiesComparison between outskirts of LBGs and of local galaxies

Possible Avenues for CollaborationPossible Avenues for Collaboration

1.1.Physics of PDRsPhysics of PDRs

2.2.Simulations of Galaxy Evolution incuding Simulations of Galaxy Evolution incuding treatment of star formation with moleculartreatment of star formation with molecular chemistrychemistry

3.3.Discussions concerning star formation inDiscussions concerning star formation in LBGsLBGs

SummarySummarySummarySummary

•Keck Survey for high-redshift DLAKeck Survey for high-redshift DLA --Detected 30 new DLAs with z--Detected 30 new DLAs with zabsabs=4 to 5.1=4 to 5.1

--Established metallicity evolution at 5---Established metallicity evolution at 5- significance out to z=5 significance out to z=5 factor of 2 increase in metals every ~1 Gyrfactor of 2 increase in metals every ~1 Gyr metals significantly lower than solar at all epochsmetals significantly lower than solar at all epochs factor of ~30 scatter at each z implies wide range of galaxy massesfactor of ~30 scatter at each z implies wide range of galaxy masses•ALMA Search for [C II] 158 μm line in DLAsALMA Search for [C II] 158 μm line in DLAs Promising technique for measuring DLA size and DM massesPromising technique for measuring DLA size and DM masses CIICII** selected gas may be detectable selected gas may be detectable PDR contribution is signficantPDR contribution is signficant•Search for Search for in situ in situ star formationstar formation in DLA gas around LBG core --Extended rest-frame FUV emission found out to ~10 kpc in stacked image--Extended rest-frame FUV emission found out to ~10 kpc in stacked image --Star formation efficiency of this gas a factor of 10 or more lower--Star formation efficiency of this gas a factor of 10 or more lower than in Galaxy than in Galaxy --Stars are plausible source of metals and turbulence in DLA gas--Stars are plausible source of metals and turbulence in DLA gas --May have found direct evidence for neutral-gas reservoir that replenishes--May have found direct evidence for neutral-gas reservoir that replenishes molecular gas fueling high SFRs in LBGsmolecular gas fueling high SFRs in LBGs

•Keck Survey for high-redshift DLAKeck Survey for high-redshift DLA --Detected 30 new DLAs with z--Detected 30 new DLAs with zabsabs=4 to 5.1=4 to 5.1

--Established metallicity evolution at 5---Established metallicity evolution at 5- significance out to z=5 significance out to z=5 factor of 2 increase in metals every ~1 Gyrfactor of 2 increase in metals every ~1 Gyr metals significantly lower than solar at all epochsmetals significantly lower than solar at all epochs factor of ~30 scatter at each z implies wide range of galaxy massesfactor of ~30 scatter at each z implies wide range of galaxy masses•ALMA Search for [C II] 158 μm line in DLAsALMA Search for [C II] 158 μm line in DLAs Promising technique for measuring DLA size and DM massesPromising technique for measuring DLA size and DM masses CIICII** selected gas may be detectable selected gas may be detectable PDR contribution is signficantPDR contribution is signficant•Search for Search for in situ in situ star formationstar formation in DLA gas around LBG core --Extended rest-frame FUV emission found out to ~10 kpc in stacked image--Extended rest-frame FUV emission found out to ~10 kpc in stacked image --Star formation efficiency of this gas a factor of 10 or more lower--Star formation efficiency of this gas a factor of 10 or more lower than in Galaxy than in Galaxy --Stars are plausible source of metals and turbulence in DLA gas--Stars are plausible source of metals and turbulence in DLA gas --May have found direct evidence for neutral-gas reservoir that replenishes--May have found direct evidence for neutral-gas reservoir that replenishes molecular gas fueling high SFRs in LBGsmolecular gas fueling high SFRs in LBGs