Lisa Kewley - kewley@ifa.hawaii.edu

Lisa Kewley U. Hawaii

Margaret Geller (SAO), Betsy Barton (UC Irvine)

Lisa Kewley - kewley@ifa.hawaii.edu

MotivationMotivation

Metallicity diagnosticsMetallicity diagnostics

Luminosity-Metallicity RelationLuminosity-Metallicity Relation

Central Star FormationCentral Star Formation

Blue BulgesBlue Bulges

Merger ModelsMerger Models

Conclusions & Future WorkConclusions & Future Work

SummarySummary

Lisa Kewley - kewley@ifa.hawaii.edu

Effect of mergers

on metallicity?unknown

Predicted gas flows?elusive

Fabbiano et al. (2004)

MotivationMotivationFeSiMg

Lisa Kewley - kewley@ifa.hawaii.edu

502 galaxies from the CfA redshift catalog (v > 2300 km/s, v < 1035 km/s, D < 77 h-1 Mpc)

Nuclear spectra for ~200 galaxies in pairs (Barton et al. 2000)

Galaxy PairsGalaxy Pairs

198 galaxies from the CfA redshift catalog

full range in Hubble type & Magnitudes in CfA survey (Jansen et al. 2000) http://cfa-www.harvard.edu/~jansen/nfgs/nfgssample.html

Field GalaxiesField Galaxies

Lisa Kewley - kewley@ifa.hawaii.edu

Kewley & Dopita (2002, ApJS, 142, 35)

“R23”

Metallicity DiagnosticsMetallicity Diagnostics

Also: Pagel (1979), McCall et al. (1985), ...,Also: Pagel (1979), McCall et al. (1985), ...,Skillman et al. (1989), McGaugh (1991),...,Skillman et al. (1989), McGaugh (1991),...,Zaritsky et al. (1994), Charlot (2001), ...Zaritsky et al. (1994), Charlot (2001), ...

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2005, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

Lisa Kewley - kewley@ifa.hawaii.edu

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity Effect?Luminosity Effect?

close pairs

wwide pairs

NFGScz < 2300 km/s

Need 1-2 Mag rise

Lisa Kewley - kewley@ifa.hawaii.edu

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity Effect?Luminosity Effect?

close pairs

wwide pairs

NFGScz < 2300 km/s

No shift in upperbound : MB

Negative shift in right bound: metallicity

Lisa Kewley - kewley@ifa.hawaii.edu

Luminosity Effect?Luminosity Effect?

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

R-Band Luminosity-metallicity Relation

1. still shifts for close pairs

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

metallicity effect?gas infall?

Lisa Kewley - kewley@ifa.hawaii.edu

Central Burst Strength, SCentral Burst Strength, SRR(t)(t)

Barton, Geller & Kenyon (2003):

Stellar population synthesis models + colors + EWsassuming 2 populations (old & young)

SR(t) = current fraction of R-band light from young burst

Lisa Kewley - kewley@ifa.hawaii.edu

Central Central Burst Burst

StrengthStrength

Barton, Geller & Kenyon (2003)

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

2. correlated with central burst strength

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

2. correlated with central burst strength

Lisa Kewley - kewley@ifa.hawaii.edu

Blue BulgesBlue Bulges

Kannappan et al. (2003): “blue bulge parameter”

(B-R) = (B-R)outer - (B-R)inner

where (B-R)outer = (B-R) at 75% light radius

(B-R)inner = (B-R) at 1/2 light radius

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

2. correlated with central burst strength

3. correlated with blue bulges

Blue Bulges

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity GradientMetallicity Gradient

Kewley, Geller, & Barton (2005, AJ, submitted)

Keck LRIS Spectroscopy

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity GradientMetallicity Gradient

Kewley, Geller, & Barton (2005, AJ, submitted)

Keck LRIS Spectroscopy

See also:Li Hsin Chien’sPoster

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Images Courtesy Chris Mihos

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2006, AJ, 131, 2004)

Luminosity-metallicity Relation

1. shifts for close pairs

2. correlated with central burst strength

3. correlated with blue bulges

Evidence for Gas Infall

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity GradientsMetallicity Gradients

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity GradientsMetallicity Gradients

M101

Kennicutt, Bresolin & Garnett (2003)

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Iono et al. (2004): Simulations predict:

1. Gas inflow rate ~ 7 Mo/yr 2. Gas flows within 1st 100 Myr but before disk merger

.

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Iono et al. (2004): Simulations predict:

1. Gas inflow rate ~ 7 Mo/yr 2. Gas flow within 100 Myr but before disk merger

.

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Assuming:1. Gas inflow rate ~ 7 Mo/yr2. Normal Spiral Metallicity gradient

.

How much infalling gas is required?

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Assuming:1. Gas inflow rate ~ 7 Mo/yr2. Normal Spiral Metallicity gradient

.

How much central dilution is required? 50-60%

Merger models predict: 60% infall

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Assuming:1. Gas inflow rate ~ 7 Mo/yr2. Normal Spiral Metallicity gradient 3. Central Gas Mass 108 - 109 Mo ave v. high

.

How long will it take to infall?

.

Lisa Kewley - kewley@ifa.hawaii.edu

Merger ScenarioMerger Scenario

Assuming:1. Gas inflow rate ~ 7 Mo/yr2. Normal Spiral Metallicity gradient 3. Central Gas Mass 108 - 109 Mo

.

How long will it take to infall? 9x106 - 9x107 years

Merger models predict: within 1x108 years

.

Lisa Kewley - kewley@ifa.hawaii.edu

New Theoretical ModelsNew Theoretical Models

Josefa Perez et al. (2006, astro-ph/0605131)

Chemical evolution model (Scannappieco et al. 2005)

CDM model (GADGET-2; Springel & Hernquist 2003)

Lower mean central (O/H) in pairs from inflows

+

Lisa Kewley - kewley@ifa.hawaii.edu

Close galaxy pairs have lower than field Close galaxy pairs have lower than field central metallicitiescentral metallicities

““Smoking gun” Smoking gun” for gas infall during merger?for gas infall during merger?

Central metallicity correlates with: Central metallicity correlates with:

central burst strengthcentral burst strength blue bulgesblue bulges

Timescale consistent with current Timescale consistent with current merger simulationsmerger simulations

ConclusionsConclusions

Lisa Kewley - kewley@ifa.hawaii.edu

Keck LRIS spectra of matched pair membersKeck LRIS spectra of matched pair members

Merger simulations of metallicity gradientsMerger simulations of metallicity gradients

Future DirectionsFuture Directions

Lisa Kewley - kewley@ifa.hawaii.edu

Starburst99-Mappings On-LineStarburst99-Mappings On-LineL. Kewley & C. LeithererL. Kewley & C. Leitherer

Interactive web form to run modelsInteractive web form to run models

Pre-run model gridsPre-run model grids

Starburst99-Mappings Interface: http://www.stsci.edu/science/starburst99/

Mappings Interface: http://www.ifa.hawaii.edu/~kewley/Mappings

Lisa Kewley - kewley@ifa.hawaii.edu

Effect of mergers

on metallicityis unknown

Fabbiano et al. (2004)

MotivationMotivationFeSiMg

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity Diagnostic ComparisonsMetallicity Diagnostic Comparisons

Kewley & Ellison (2005)

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity: Metallicity: Strong lines vs Auroral LinesStrong lines vs Auroral Lines

Garnett, Kennicutt, Bresolin

Lisa Kewley - kewley@ifa.hawaii.edu

Classification Classification SchemeScheme

Lisa Kewley - kewley@ifa.hawaii.edu

Galaxy PairsGalaxy Pairs

Kewley, Geller, & Barton (2005, AJ, submitted)

Luminosity-metallicity Relation

1. shifts for close pairs

2. correlated with central burst strength

3. correlated with blue bulges

Evidence for Gas Infall

1’

Lisa Kewley - kewley@ifa.hawaii.edu

Kobulnicky & Kewley (2004, ApJ, 617,240)

GOODS Survey: 0.3 < z< 1 GOODS Survey: 0.3 < z< 1

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity - [NII]/HaMetallicity - [NII]/Ha

Pettini & Pagel (2004)

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity DiagnosticsMetallicity Diagnostics

1.1. TheoreticalTheoretical - photoionization models - photoionization models e.g., McGaugh (1991), Kewley & Dopita (2002), e.g., McGaugh (1991), Kewley & Dopita (2002),

Tremonti et al. (2004)Tremonti et al. (2004)

2.2. EmpiricalEmpirical - fit to T - fit to Tee metallicities metallicities e.g., Pilyugin (2000), Pettini & Pagel (2004)e.g., Pilyugin (2000), Pettini & Pagel (2004)

CombinationCombination - fit to T - fit to Tee method + method + theoretical metallicitiestheoretical metallicities e.g., Denicolo, Terlevich & Terlevich (2002)e.g., Denicolo, Terlevich & Terlevich (2002)

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity - [OIII]/Hb,[NII]/HaMetallicity - [OIII]/Hb,[NII]/Ha

Pettini & Pagel (2004)

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity Metallicity Diagnostic Diagnostic

ComparisonsComparisons

Kewley & Ellison (2005, in prep)

Lisa Kewley - kewley@ifa.hawaii.edu

Metallicity: Metallicity: Strong lines vs Auroral LinesStrong lines vs Auroral Lines

Garnett, Kennicutt, Bresolin

Lisa Kewley - kewley@ifa.hawaii.edu

Kobulnicky & Kewley (2004, ApJ, 617, 240)

GOODS Survey: 0.3 < z< 1 GOODS Survey: 0.3 < z< 1

Lisa Kewley - kewley@ifa.hawaii.edu

Auroral Line SaturationAuroral Line Saturation

Stasinska (2002,2005)