HI Column Densities, Kinematics, and Metallicities in Strong MgII

Absorbers

Dave TurnshekUniversity of Pittsburgh

Outline:Outline: Strong MgII Absorbers (low ionization, neutral gas)Strong MgII Absorbers (low ionization, neutral gas)

HI Column Densities (DLAs and sub-DLAs)HI Column Densities (DLAs and sub-DLAs) KinematicsKinematics Element AbundancesElement Abundances

Model ImplicationsModel Implications DLA Absorbing Galaxies DLA Absorbing Galaxies

Selection Effects (esp. MgII)Selection Effects (esp. MgII)

Pittsburgh Collaborators:Pittsburgh Collaborators: Sandhya RaoSandhya Rao Michele Belfort-MihalyiMichele Belfort-Mihalyi Daniel Nestor (now U. Florida)Daniel Nestor (now U. Florida) Anna Quider Anna Quider + SDSS collaborators …+ SDSS collaborators …

Strong MgII AbsorbersStrong MgII Absorbers(MgII(MgII2796 REW > 0.3 Å)2796 REW > 0.3 Å)

Detected in large numbers at 0.4 < z < 2.2 Detected in large numbers at 0.4 < z < 2.2 by SDSS (e.g., Nestor, Turnshek, Rao 2005)by SDSS (e.g., Nestor, Turnshek, Rao 2005)

Selection biased by gas cross sectionSelection biased by gas cross section

Tracers for DLAs when REW2796 > 0.6 Å Tracers for DLAs when REW2796 > 0.6 Å (Rao, Turnshek, Nestor 2005)(Rao, Turnshek, Nestor 2005)

Remainder are mostly sub-DLAs Remainder are mostly sub-DLAs (incomplete?)(incomplete?)

MgIIMgII2796 REW 2796 REW DistributionDistribution

Left: Left: MMT + MMT + SDSSSDSS

Right: Right: SDSS SDSS alonealone

Incidence of MgII REWs: z = 0.4 Incidence of MgII REWs: z = 0.4 2.22.2

Dashed: no Dashed: no evolution evolution curve (NEC)curve (NEC)

Larger Larger REWs REWs decrease decrease relative to relative to NEC at NEC at decreasing decreasing redshiftredshift

HI Column DensitiesHI Column Densities

Rao, Turnshek, Nestor (2005):Rao, Turnshek, Nestor (2005): HST UV spectra of 197 strong MgII absorbers HST UV spectra of 197 strong MgII absorbers

MgIIMgII2796 REW > 0.6 Å:2796 REW > 0.6 Å: DLA fraction increases with increasing REWDLA fraction increases with increasing REW Mean N(HI) = 4(10Mean N(HI) = 4(102020) atoms/cm) atoms/cm2

0.3 Å < MgII0.3 Å < MgII2796 REW < 0.6 Å:2796 REW < 0.6 Å: Mean N(HI) = 10Mean N(HI) = 101919 atoms/cm atoms/cm2

Mean HI Column DensitiesMean HI Column Densities(all strong MgII absorbers)(all strong MgII absorbers)

Mean HI Column DensitiesMean HI Column Densities

all strong MgIIs: only MgII DLAs:

Strong MgII Absorber Strong MgII Absorber KinematicsKinematics

Doublet ratios indicate that strong MgIIs are saturated. Their REWs are mainly indicators of absorptionvelocity spread.

e.g., Petitjean (1998)

DLA Fraction and Mean HI DLA Fraction and Mean HI Column Density vs. REW in Column Density vs. REW in

Velocity UnitsVelocity Units(all strong MgII absorbers)(all strong MgII absorbers)

REW is given inunits of km/s instead of Åon the top horizontal axis.

Element Abundances Element Abundances in Strong MgII Absorbersin Strong MgII Absorbers

Use SDSS composite spectra (high S/N)Use SDSS composite spectra (high S/N)

MgII2796 REW measures kinematicsMgII2796 REW measures kinematics

Metallicities from weak unsaturated linesMetallicities from weak unsaturated lines

Study metallicity - kinematics correlationsStudy metallicity - kinematics correlations

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation

(ZnII, CrII, MgII SDSS (ZnII, CrII, MgII SDSS Composites)Composites)

Approximately6000 strongMgII absorbers.

Also seen inSiII, FeII, and MnII.

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation

(ZnII and CrII SDSS Composites)(ZnII and CrII SDSS Composites)

Approximately6000 strongMgII absorbers.

MgII2796 REWintervals notedin units of km/s.

ZnII CrII

DLA Fraction and Mean HI DLA Fraction and Mean HI Column Density versus Column Density versus

Velocity SpreadVelocity Spread(all strong MgII absorbers)(all strong MgII absorbers)

REW is given inunits of km/s instead of Åon the top horizontal axis.

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation

(Zn, Cr, Si, Mn, and Fe)(Zn, Cr, Si, Mn, and Fe)

rare largeREW systems

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation(Zn and Cr)(Zn and Cr)

(more depletion)

(little depletion)

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation(Zn and Si)(Zn and Si)

(-enhancement)

Metallicity–Kinematics Metallicity–Kinematics CorrelationCorrelation

(Keck HIRES data, z=1.74.2, taken from Prochaska et al.)

Model Implications Model Implications (z=0.5(z=0.52)2)

Kinematic spread at z=1Kinematic spread at z=12 consistent with 2 consistent with predictions of Mo, Mao, White (1998) predictions of Mo, Mao, White (1998)

DLA galaxy impact parameters at z<1 DLA galaxy impact parameters at z<1 consistent with Mo, Mao, White (1998) consistent with Mo, Mao, White (1998) predictions at z=1predictions at z=1

Implications for cosmic SFRImplications for cosmic SFR DLAs different from LBGs (Mo, Mao, White 1998)DLAs different from LBGs (Mo, Mao, White 1998) Application of Kennicutt’s Schmidt Law to DLAs Application of Kennicutt’s Schmidt Law to DLAs

suggests DLAs contribute at low-z, not at high-z suggests DLAs contribute at low-z, not at high-z (Hopkins, Rao, Turnshek 2005; Rao talk)(Hopkins, Rao, Turnshek 2005; Rao talk)

DLA Fraction and Mean HI DLA Fraction and Mean HI Column Density versus Column Density versus

Velocity SpreadVelocity Spread(all strong MgII absorbers)(all strong MgII absorbers)

REW is given inunits of km/s instead of Åon the top horizontal axis.

Kinematics and Impact Kinematics and Impact ParameterParameter

(Mo, Mao, White 1998)(Mo, Mao, White 1998)

DLA Galaxy Properties (z<1)DLA Galaxy Properties (z<1)(updated from Rao et al. 2003)(updated from Rao et al. 2003)

Selection EffectsSelection Effects The probability of detecting a DLA absorber is The probability of detecting a DLA absorber is

the product of their comoving number the product of their comoving number density times their gas cross section.density times their gas cross section.

Could we be missing very high N(HI) Could we be missing very high N(HI) absorbers with low neutral gas cross section?absorbers with low neutral gas cross section? Detection of one low cross section system with Detection of one low cross section system with

N(HI) = 10N(HI) = 102323 atoms/cm atoms/cm2 would require doubling would require doubling ΩΩHI

MgII REW selection biasMgII REW selection bias Not relevant Not relevant ΩΩHI [since mean N(HI) flat with REW] [since mean N(HI) flat with REW] Relevant for cosmic metallicity and DLA galaxy IDsRelevant for cosmic metallicity and DLA galaxy IDs

Ultra-StrongUltra-StrongMgII FieldsMgII Fields

Recent WIYN Recent WIYN observations of observations of Nestor et al.Nestor et al.

Example of an Ultra-Strong Example of an Ultra-Strong MgIIMgII

FeII region MgII + MgI region

DLA Galaxy Properties (z<1)DLA Galaxy Properties (z<1)(updated from Rao et al. 2003)(updated from Rao et al. 2003)

Summary: Strong MgII Summary: Strong MgII AbsorbersAbsorbers

Galaxies Selected by Gas Cross-Section Galaxies Selected by Gas Cross-Section

HST UV: N(HI) – kinematics correlationHST UV: N(HI) – kinematics correlation

SDSS: kinematics – metallicity correlationSDSS: kinematics – metallicity correlation

Consistency with Mo, Mau, White (1998)?Consistency with Mo, Mau, White (1998)?

MgII selection effects need to be MgII selection effects need to be incorporatedincorporated

Extras …Extras …

DLA Galaxy Properties (z<1)DLA Galaxy Properties (z<1)(updated from Rao et al. 2003)(updated from Rao et al. 2003)

PKS 1127-145 PKS 1127-145

IRTF K-IRTF K-band band imaging imaging of DLA of DLA field at field at z=0.313z=0.313..

Strong MgII Nearest Strong MgII Nearest Neighbors Neighbors

IRTF K-IRTF K-band band imaging imaging of DLA of DLA and and sub-DLA sub-DLA fields at fields at z<1.z<1.

Strong MgII Nearest Strong MgII Nearest Neighbors Neighbors

IRTF K-IRTF K-band band imaging imaging of DLA of DLA and and sub-DLA sub-DLA fields at fields at z<1.z<1.

Schmidt LawSchmidt Law

from Kennicutt (1998)from Kennicutt (1998)

DLAs and Cosmic Star DLAs and Cosmic Star FormationFormation

Hatched Hatched region: region: observed observed cosmic cosmic SFRSFR

Filled Filled circles: circles: DLAsDLAs

Hopkins, Rao, Turnshek (2005)

DLAs and Cosmic Star DLAs and Cosmic Star FormationFormation

Hatched Hatched regions: regions: neutral gas neutral gas and and stellar stellar mass mass densities densities predicted predicted from from observed observed cosmic SFRcosmic SFR

Filled Filled circles: circles: DLAsDLAs

Hopkins, Rao, Turnshek (2005)

DLAs and Cosmic Star DLAs and Cosmic Star FormationFormation

Hatched Hatched region: region: metals metals predicted predicted from from observed observed cosmic cosmic SFRSFR

Filled Filled circles: circles: metals metals from from DLAsDLAs

Hopkins, Rao, Turnshek (2005)

DLA Fraction in Strong DLA Fraction in Strong MgIIsMgIIs

Mean HI Column DensitiesMean HI Column Densities

all strong MgIIs: only MgII DLAs:

Evolution of Incidence of Evolution of Incidence of DLAsDLAs

Lower curve: Lower curve: no-evolutionno-evolution

incidence is incidence is product of product of absorber cross-absorber cross-section times section times absorber absorber number densitynumber density

Rao, Turnshek, Nestor (2005)

Evolution of HI Evolution of HI Cosmological Mass Density Cosmological Mass Density

from DLAsfrom DLAs

DLA neutral DLA neutral gas mass is gas mass is ≈ constant at ≈ constant at z=0.5z=0.54.5, 4.5, but is 2 times but is 2 times lower at z=0.lower at z=0.

Rao, Turnshek, Nestor (2005)

SDSS Spectrum of MgII SDSS Spectrum of MgII AbsorptionAbsorption

z=0.741 MgII absorption system (REW2796 = 2.95Angstroms)z=0.741 MgII absorption system (REW2796 = 2.95Angstroms)

Right: Strong MgII doublet and weakerMgI line.

Left: Two Strong FeII lines and threeweaker MnII lines.

H I 21 cm Maps of Some Nearby Galaxies:

VLA and WSRT maps courtesy John Hibbard, NRAO

H I 21 cm Maps of Some Nearby Galaxies:

VLA and WSRT maps courtesy John Hibbard, NRAO

H I 21 cm Maps of Some Nearby Galaxies:

VLA and WSRT maps courtesy John Hibbard, NRAO

Identification of MgII Absorbing Identification of MgII Absorbing GalaxiesGalaxies

Hubble SpaceTelescope imageof a field withseveral quasar absorption linesystem galaxiesidentified. A galaxy at the DLA redshift (z=0.656) is not visible.

Courtesy Chuck Steidel

Quasar 3C336Sightline

Identification of DLA Absorbing Identification of DLA Absorbing GalaxiesGalaxies

Infrared K-band image of the Q0738+313 sightline with DLAs at z = 0.091 and z = 0.221. IDs put the galaxies at 0.08 and 0.1L*, respectively.

Turnshek et al. 2001

Optical Images of Stars in M51:Courtesy NOAO

Deep exposure Short exposure

Evolution of Neutral Gas Metal Evolution of Neutral Gas Metal AbundanceAbundance

Beginning Beginning to measure to measure abundanceabundances at lower-s at lower-z, seeing z, seeing evidence evidence for for evolution.evolution.

Rao et al. 2004

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