Neutral Gas Reservoirs from z=0 to z ~ 5 Neutral Gas Reservoirs from z=0 to z ~ 5 Art Wolfe Marc Rafelski: UCSD Marcel Neeleman: UCSD Michele Fumagali: UCSC J. Xavier Prochaska: UCSC Hsiao-Wen Chen: U. Chicago Marc Rafelski: UCSD Marcel Neeleman: UCSD Michele Fumagali: UCSC J. Xavier Prochaska: UCSC Hsiao-Wen Chen: U. Chicago

DLAS are Definition of Damped Ly System (DLA): N(HI) cm -2 Distinguishing characteristics of DLAs : (1) Gas is Neutral (2) Metallicity is low: [M/H]=-1.3 (3) Molecular fraction is low:f H2 ~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 Ly System (DLA): N(HI) cm -2 Distinguishing characteristics of DLAs : (1) Gas is Neutral (2) Metallicity is low: [M/H]=-1.3 (3) Molecular fraction is low:f H2 ~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 II Fe II Damped Ly Absorption Systems

Comoving HI mass density from Damped Lyα Systems

ρ * (z=0)

Replenishment of H I requiredReplenishment of H I requiredReplenishment of H I requiredReplenishment of H I required

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

How are DLAs Related to Galaxies? Do DLA metallicities resemble those of Do 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 and Relationship Between Absorbing Gas and Known Star-Forming Galaxies, i.e. LBGs? Known Star-Forming Galaxies, i.e. LBGs?

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

ESI Survey for high-z DLAs high-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 z z=5.179 z=4.820 z=4.797

[M/H] from S II and Si II, and Ly [M/H] from S II and Si II, and Ly SII SiI I SII SiII SiII

Metal Abundances and versus redshift (2004 sample)

2004 sample + new ESI DLAs

Metal Abundance versus look-back time

Comparison between Metallicity distributions of DLAs with z=2-3 and Galaxy stellar populations Pettini (2006)

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

ALMA Search for [C II] 158 μm Emission from DLAs (Wolfe, Neeleman, Fumagali, Prochaska et al. 2011) ALMA Search for [C II] 158 μm Emission from DLAs (Wolfe, Neeleman, Fumagali, Prochaska et al. 2011)

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

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

Obtaining Cooling Rates from C II* Absorption [C II] 158 micron transition dominates cooling of neutral gas in Galaxy ISM Spontaneous emission rate per atom l c =n [CII] obtained from strength of absorption and Lyman alpha absorption Thermal balance condition l c = pe gives heating rate per atom for cold neutral-medium (CNM) lclc =

Metal-line velocity profiles for 3 DLAs with highest z z=5.179 z=4.820 z=4.797

Bimodal Distribution of Cooling Rates l c

H I Contours on 158 μm image of simulated galaxies at z=2.3 (Fumagali etal. 2010) z=2.3 (Fumagali etal. 2010) M h =6×10 11 M M h =6×10 11 M SFR=100 M y -1 SFR=100 M y -1 S ν =4 mJy S ν =4 mJy M h =2×10 11 M M h =2×10 11 M SFR=7 M y -1 SFR=7 M y -1 S ν =0.8 mJy S ν =0.8 mJy

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

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

Search for low surface-brightness emission from star-forming gas surrounding LBG cores star-forming gas surrounding LBG cores (Rafelski, Wolfe, & Chen 2011) Search for low surface-brightness emission from star-forming gas surrounding LBG cores star-forming gas surrounding LBG cores (Rafelski, Wolfe, & Chen 2011) Test Kennicutt-Schmidt law for star formation Test Kennicutt-Schmidt law for star formation in the outskirts of LBGs in the outskirts of LBGs Σ SFR (N)=K kenn (N/N c ) β ; β=1.4 Σ SFR (N)=K kenn (N/N c ) β ; 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 outer atomic-dominated gas situated in the outer regions of nearby galaxies. regions of nearby galaxies.

Star Formation in Atomic-Dominated Gas M83: H I Contours superposed on Galex FUV image (Biegel etal. 2010)

UDF Sample of compact, symmetric LGBs

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

Surface-brightness Profile of Stacked Image

Comoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I Gas Differential:Differential: + +…

Comoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I Gas Differential:Differential: + +…

Comoving SFR Density Predicted for H I Gas Comoving SFR Density Predicted for H I Gas Differential:Differential: + +… Transform from N to intensityTransform from N to intensity

Predicted Surface Brightness vs comoving SFR density

Theory Confronts Observation

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

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

Comparison between outskirts of LBGs and of local galaxies

Possible Avenues for Collaboration 1.Physics of PDRs 2.Simulations of Galaxy Evolution incuding treatment of star formation with molecular treatment of star formation with molecular chemistry chemistry 3.Discussions concerning star formation in LBGs LBGs

SummarySummary Keck Survey for high-redshift DLAKeck Survey for high-redshift DLA --Detected 30 new DLAs with z abs =4 to Detected 30 new DLAs with z abs =4 to Established metallicity evolution at 5- significance out to z=5 --Established metallicity evolution at 5- significance out to z=5 factor of 2 increase in metals every ~1 Gyr factor of 2 increase in metals every ~1 Gyr metals significantly lower than solar at all epochs metals significantly lower than solar at all epochs factor of ~30 scatter at each z implies wide range of galaxy masses factor of ~30 scatter at each z implies wide range of galaxy masses ALMA Search for [C II] 158 μm line in DLAs ALMA Search for [C II] 158 μm line in DLAs Promising technique for measuring DLA size and DM masses Promising technique for measuring DLA size and DM masses CII * selected gas may be detectable CII * selected gas may be detectable PDR contribution is signficant PDR contribution is signficant Search for in situ star formationSearch for in situ star 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 LBGs molecular gas fueling high SFRs in LBGs Keck Survey for high-redshift DLAKeck Survey for high-redshift DLA --Detected 30 new DLAs with z abs =4 to Detected 30 new DLAs with z abs =4 to Established metallicity evolution at 5- significance out to z=5 --Established metallicity evolution at 5- significance out to z=5 factor of 2 increase in metals every ~1 Gyr factor of 2 increase in metals every ~1 Gyr metals significantly lower than solar at all epochs metals significantly lower than solar at all epochs factor of ~30 scatter at each z implies wide range of galaxy masses factor of ~30 scatter at each z implies wide range of galaxy masses ALMA Search for [C II] 158 μm line in DLAs ALMA Search for [C II] 158 μm line in DLAs Promising technique for measuring DLA size and DM masses Promising technique for measuring DLA size and DM masses CII * selected gas may be detectable CII * selected gas may be detectable PDR contribution is signficant PDR contribution is signficant Search for in situ star formationSearch for in situ star 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 LBGs molecular gas fueling high SFRs in LBGs