A Method for Obtaining Detailed Abundances of Extragalactic Globular Clusters w/ Andy McWilliam (Carnegie Obs.) Scott Cameron, Janet Collucci (UM) MW- 47TucNGC 5128 LMC- NGC 2005

Galaxy #1, Milky Way: Formation: halo  bulge/thick disk  thin disk Evidence: abundances (Fe,O,Mg,Eu…) & kinematics (bulk, streams) (1) Stars: *timescales*, substructure ( recent: Ivans et al 2003) The goal: formation histories of galaxies halo thick bulge thin Prochaska et al 2004Yanny et al 2003

Galaxy #1, Milky Way: Formation: halo  bulge/thick disk  thin disk Evidence: abundances & kinematics (2) Globular clusters: easy targets! date-able! old! The goal: formation histories of galaxies Parmentier et al 2000

Formation history of other galaxies: Local Group: getting details (limitation: flux) Evidence: Supergiants ( Venn et al 04, McWilliam & Smecker-Hanes 04 ) bright = young! (no history) Venn et al 2004

Formation history of other galaxies: Beyond…: different tools (limitation: flux & resolution) Evidence: integrated light - broad-band colors + [stellar population models] general: red (old/metal-rich) blue (young/metal-poor) - line indices + [stellar population models] Lick System (Worthey et al, Trager et al, Gonzalez et al), Rose

Formation history of other galaxies: Worthy 1998 Age Z blue Beyond: low resolution spectra (>2Å) + stellar population models Limitations: 1- Age/metallicity degenerate (young/z-rich  old/z-poor) 2- z vs Fe ? Mg, O,Ca…? calibration: abundances ratios? * multiple generations of star formation.

Formation history of other galaxies : Forbes et al. 04 Age Z Beyond: low resolution spectra (>2Å) + stellar population models Limitations: 1- Age/metallicity degenerate (young/z-rich  old/z-poor) 2- z vs Fe ? Mg,O,Ca…? calibration: abundances ratios? Recent: Principle component analysis: PC1  metallicity Strader,Brodie ’04,Burstein et al 04 Globular clusters*

Formation history of other galaxies : Forbes et al. 04 Beyond: integrated light of GCs Principle component analysis: PC1  metallicity Forbes et al.’04, Strader,Brodie ’04, Burstein et al 04 [Fe/H] ( or z):  0.1 dex (optimistic?) Age:  3 Gyrs [E/Fe]:  (?) (“  ” or “enhanced”) C,N; O,Mg,Si,Ca; Cr; Na produced in SNII, SNI, and AGB stars Missing: z vs. Fe vs. , self-enrichment, IMF **M31: young (0.5-5Gyr), disk GC system (Beasley 04, Burstein 04, Morrison 04)

Why high resolution? [Fe/H]  -1 Perrett et al 2002, M31 Globular cluster spectra: 5.1 Å 0.17 Å Mg 2 Mg b

Why globular clusters? E, Sa galaxies:  v  150km (R  850) Milky Way GCs:  v  2-18 (R  7-60 k) -7 > M v > -9 10,000 < R < 30,000

Element-yield review: < 2M  : H  C 2-8M  :H  C/O/Ne, n-capture (s-process) [binary] SN Type I: Fe-peak 8-30M  : H  Fe, SN Type II: Fe-peak,  -elements, n-capture (r-process) Punch line: “  -elements” …………………SN II:fast (Myrs) (O,Mg, Si,S,Ca, Ti; Al,Na?) Fe:…………………………………SN I: slow (Gyrs) SN II:fast Fe-peak (21-30p) :………… SN I: slow (Sc, V, Cr, Mn, SN II:fast Co, Ni, Cu, Zn) Fe-dep. yields? Heavy (Ba, Y, Zr, La, Sr…) …………SN I: slow (Eu, Sm, Nd…) …………………SN II:fast Why get detailed abundances? Prochaska et al 2000, Bensby et al 2004 halo thick bulge thin

Element-yield review:  (X) = relative number = (x/H) = log (N(X)/N(H)) + 12 [Fe/H] = log(Fe/H) - log(Fe/H)  [X/Fe] =  (X/Fe) -  (X/Fe)  z = mass fraction beyond He z  = halo thick bulge thin Why get detailed abundances? Prochaska et al 2000 deficient enriched Metal poor

[  /Fe] vs [Fe/H]: formation timescale [Eu/Fe]: r-process (SNII) IMF, nucleosynthesis [Ba/Fe] : s-process (SNI, low-m), IMF, nucleosynthesis Why get detailed abundances? *1- Detailed formation of galaxy #2 2- test stellar population models 3- understand the line indices halo thick bulge thin Prochaska et al 2000 deficient enriched Metal poor

The goal: GC abundances outside the local group… Requirements: S/N  50 H  R  10,000 – 30, A MIKE + Magellan: GC limit  18 V mag Bernstein, Shectman, Gunnels, installed Nov 2002

NGC 5128: S0 (Dec = -43) D = 3.5 Mpc m-M = 27.7 GCs: M v  mag (RGB tip: v  mag) (young supergiants) Rejkuba 2001 (UVES/FORS imaging) The goal: Galaxies outside the local group…

NGC 1313: SBd (Dec = -66) D = 4.4 Mpc m-M = 28 GC: v  mag (RGB tip: v  mag)

High resolution analysis — A Training Set The Milky Way Globular Clusters (  = mag/asec 2 ):

High resolution analysis — A Training Set [Fe/H] = -2.0  v = 4km/s V = -6 mag vs [Fe/H]=-0.76  v = 12km/s V = -9 mag Milky Way GCs: GC Integrated Light Spectra (ILS) at different abundances & masses

High resolution analysis — A Training Set NGC 104 (47Tuc): [Fe/H] =  v = 12 km/s V = -9 mag Eu in RGB: EW= 16 mÅ! Milky Way GCs: ILS spectrum vs single RGB

A Training Set: Milky Way: 7 clusters (  = mag/asec 2 ): [Fe/H] Mv ngc ngc ngc ngc ngc ngc 104(47Tuc) ngc LMC: 7 clusters to date (m-M=18.5, m v =10 mag,  v = mag/asec 2 ) ngc 2019, 2005[Fe/H] ≈ -2.0old (>5 Gyr) ngc 1866, 1978[Fe/H] ≈ ?intermediate ( Gyr) ngc 1711, 2002, 2100[Fe/H] ≈ -0.6young (<0.1 Gyr)

Training Set: observations Milky Way (6) + LMC (8) : Integrated light spectra 32”x32” 12”x12” 1”x4” slit MW: 47Tuc LMC: n1711 individual stars

Training Set: analysis? Individual stars: EW obs vs. Modeled stellar atmospheres - Kurucz stellar atmosphere grids (ATLAS9) T eff *( B-V) obs log g *(V) obs  *(1-2 km/s) [Fe/H]  mass,T,P,N(e-) - MOOG (Sneden 1998), for each line:, EP, loggf,  (X)  EW mod *tune to get same  (Fe) for all FeI,II lines.

Training Set: analysis Integrated light: EW obs vs ??? Build up an atmosphere model. RESOLVED globular cluster --> observed CMD!

Training Set: analysis Integrated light: EW obs vs composite model atmosphere - Kurucz stellar atmosphere grids (ATLAS9) T eff ( B-V) obs log g (V) obs   log g [Fe/H] - MOOG (Sneden v.1998), for each line:, EP, loggf,  (X)  EW per box.  Combine to get light-weight EW * NO PARAMETER TUNING

Training Set: step 0 - observed CMD RESOLVED globular cluster --> observed CMD! Training set issues: scanned core only! rare stars not included.

Training Set: step 0 - observed CMD (n6397) NGC 6397: Stable FeI solution: Is  (Fe) stable with lines’ Excitation Potential Checks T eff, reddening: Population of energy state depends on T

Training Set: step 0 - observed CMD (n6397) NGC 6397: Stable FeI solution:Is  (Fe) stable with lines’ wavelength Checks fraction of flux from hot/cool stars: blue light -- from hot stars with weak lines red light -- cool stars with strong lines.

Training Set: step 0 - observed CMD (n6397) NGC 6397: Stable FeI solution: Is  (Fe) stable with lines’ EW. Checks  (  log g, 1-2 km/s) Microturbulence decreases saturation of strong lines. (0km/s larger covering factor in wavelength space. Larger velocities “spread” the atoms in wavelength space, decreasing saturation.)

Training Set: step 0 - observed CMD (n6397) Balmer lines: equivalent widths (EW) and profiles example: NGC member RGB star NGC ILS 47 Tuc - ILS Broadened by hot stars Age/Metallicity: Old/metal-rich = red (cool) Young/metal-poor = blue (hot)

Training Set: step 0 - observed CMD (n6397) Balmer lines: H , H , H , H  — EW and profiles — ILS NGC 6397 — synthesized lines from the observed CMD (w/ BHB) (w/o BHB) Age/Metallicity + HB morphology Observational constraint: flux in / color of HB (otherwise, HB is a wild card…Age? mass loss?)

Training Set: step 0 - observed CMD (n6397) ILS analysis [Fe/H] x  (x) N-lines  /  N[X/Fe][X/Fe] Cr FeI FeII NiI  -elements: MgI CaI TiI,II n-capture BaII (Castihlo 2000) NGC 6397: Derived abundances — consistent with results from single stars!

What (we think) we know from analysis of a RESOLVED GC (n6397): 1. the composite stellar models can work! 2. We have tools to identify problems! Balmer lines  T eff (CMD: reddening, {age, [Fe/H]}, HB morph) FeI (EW, EP, ) FeI vs Fe II  log g (CMD: giants vs dwarfs, age) (ionized lines sensitive to N(e-)) RECAP —

Training Set: step 1 - isochrone CMD (47Tuc) GCs are a single age population! Isochrones - stellar evolution models predict cluster CMD at given age. Padova (Girardi et al 2000) BaSTI (Pietrinferni et al 2004) + Kroupa IMF (Kroupa & Boily 2002), flattens below 0.5M  + Normalize #’s of stars to observed M v (In the case of a faint cluster, don’t make boxes w/ <1 star) What if the cluster is unresolved? (e.g. NGC )

Training Set: step 1 - isochrone CMD (47Tuc) Do they reproduce the CMD? 2 problems: 1. mass segregation (for training set) 2. AGB bump (general) 47Tuc Schiavon et al 2002 Spitzer & Hart 1971 MW: eg. Ferraro 1997 LMC: eg.Grijs et al 2002

Training Set: step 1 - isochrone CMD (47Tuc) Do they reproduce the CMD? Adjustments: 1- remove stars 3 mag below turn-off. 2- increase fraction in AGB bump.

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW and profile Models: age = 6.3 Gyr z = * note blends

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s Color = AGE NGC 6397 match: Age ≈ 6.3 Gyr [A/H] ≈ -2 Models change very little > 3 Gyrs

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s and profiles Models: age = 10 Gyr z = *note blends are worse!! (metal rich GC) Need to synthesize blended lines

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s 47Tuc match: Age ≈ Gyr [A/H] ≈ -0.9

What (we think) we know: Balmer lines T eff (CMD: reddening, {age, [Fe/H]}, HB morph) * add synthesis of blended lines age constraints are weak FeI stability w/ (EW, EP, ) T eff (CMD: reddening, {age, [Fe/H]}, HB morph) FeI vs Fe II log g (CMD: giants vs dwarfs, age) RECAP

2- FeI & FeII Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

2- FeI & FeII [FeI/H]  input [A/H]  input age Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

2- FeI & FeII [FeI/H]  input [A/H]  input age +/-0.1 !! at <1 Gyr: young = hot modeled lines=weak. at >1 Gyr: models not changing much Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

Training Set: step 2 - isochrone CMD (47 Tuc) FeI checks: no FeI slope w/ EP if:age > 2 & [A/H] < -1 w/ if: age > 3 w/ EW if:age > 3 Gyrs

2- FeI & FeII [FeI/H]  input [A/H]  input age +/ !! [FeII/H]  input [A/H]  input age Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

Training Set: step 2 - isochrone CMD (47 Tuc) The age-metallicity degeneracy!

2- FeI & FeII [FeI/H]  input [A/H]  input age +/ !! [FeII/H]  input [A/H]  input age expected age to increase giant:dwarf… g … N(e-). Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

2- FeI & FeII [FeI/H]  input [A/H]  input age +/-0.05 !! (statistical) [FeII/H]  input [A/H] (  N(e-))  input age [Fe/H]=[FeII/H]: [Fe/H]  -0.6 age = 5-16 Gyrs Best FeI solution: [Fe/H]  -0.6 (10Gyr, [A/H]=-0.68) Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, unadjusted isochrones)

Training Set: step 2 - isochrone CMD (47 Tuc) 1- iron peak x  (x)  N-lines [X/Fe][Fe/H][X/Fe] (C’04) Sc II V I Cr I Mn I Fe I , (KI’03) Fe II Ni I * Abundance results for 47Tuc! Carretta et al 2004 Kraft & Ivans 2003 (Padova, 10Gyr, [A/H]=-0.68, adjusted) Isochrone analysis (w/ mass segregation + boosted AGB dump) CONSISTENT with solution from individual stars. unambiguous [Fe/H]=0.7

Training Set: step 2 - isochrone CMD (47 Tuc) (Padova, 10Gyr, [A/H]=-0.68, adjusted) Abundance results for 47Tuc!

Training Set: step 2 - isochrone CMD (47 Tuc) 2.  -elements x  (x)  N-lines [X/Fe][X/Fe] (CG04) [O I] Mg I Si I Ca I Ti I Ti II non-alpha, light elements Na I Al I (Padova, 10Gyr, [A/H]=-0.68, adjusted) Carretta & Gratton 2004 Abundance results for 47Tuc!

Training Set: step 2 - isochrone CMD (47 Tuc) 4- neutron-capture elements (s-, r-process) x  (x)  N-lines [X/Fe][X/Fe] Y II ? (Brown+Wallerstein’89) Y I: Zr I * ? Ba II *-0.11 La II Nd II Eu II ? (Padova, 10Gyr, [A/H]=-0.68, adjusted) Abundance results for 47Tuc!

Results for 47Tuc:  -elements: Similar to halo/bulge. Exactly as expected. light-elements: (Na, Al) HIGH! Consistent with proton-burning (self-enrichment!) in GCs: Ne  Na, Mg  Al Gratton, Sneden, Carretta 2004 halo thick bulge thin

Results on 47Tuc: halo thick bulge thin Fe-Peak elements: Similar to halo/bulge. Exactly as expected.

Results on 47Tuc: Heavy elements: (r-, s-process) Similar to halo… close to solar. Sites of r-process not well known. Differences in SN yields with metallicity…

Second Training Set - LMC Important because: 1- MW GCs all age > 8 Gyrs … LMC 0.1 < Age < 5 Gyr 2- Test the standard model for chemical enrichment! [  /Fe] > 0 when metal poor, [  /Fe] ~ 0 when metal rich Single stars: Magellan+MIKE (VLT+UVES) ILS: 2.5m telescope

EXTRAGALACTIC GCs -- first round targets NGC 5128: S0, D = 3.5 Mpc m-M = 27.7 Mv  mag hghh23 Mv=18.3 B-V=1.1 (red)Peng et al hghh29 Mv=18.2 B-V=1.0 (red) hghh17 Mv=17.6 B-V=0.8 (blue) NGC 1313: SBd, D = 4.4 Mpc, m-M = 28.2 Mv  mag 379: Mv=17.6 B-V=0.27 (blue)Larson et al 1999

EXTRAGALACTIC GCs — first peak…

Next steps: 1. MW & LMC -new abundances results -mass estimates -finish the “training” 2. NGC 5128 & NGC first metallicities in *old* extragalactic environment

Training Set: step 1 - isochrone CMD (47Tuc) Do they reproduce the CMD? Adjustments: 1- remove stars 3 mag below turn-off. 2- increase fraction in AGB bump.

Training Set: observations Milky Way (6) + LMC (8) : Integrated light spectra individual stars 32”x32” 12”x12” 1”x4” slit MW: 47Tuc LMC: n1711

Training Set: step 1 - isochrone CMD (47Tuc) Do they reproduce the CMD?

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s and profiles

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s NGC 6752 match: Age ≈ 6.3 Gyr [A/H] ≈ -1.5

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s and profiles

Training Set: step 1 - isochrone CMD (4 GCs) 1- Balmer lines - H , H , H , H  EW’s n6388 match: Age ≈ 12 Gyr [A/H] ≈ -2 Age ≈ 6.3 Gyr [A/H] ≈ -1 Age ≈ 2 Gyr [A/H] ≈ -0.4

Galaxy #1, Milky Way: Formation: halo  bulge/thick disk  thin disk Evidence: abundances (Fe,O,Mg,Eu…) & kinematics (bulk… streams) Stars (Ivans et al 2003: halo substructure… #SNI/II) The goal: formation histories of galaxies halo thick bulge thin Prochaska et al 2004Odenkirchen et al 2002

Formation history of other galaxies: Beyond…: coarse information Evidence: integrated light -- “z” + bulk kinematics - broad-band colors + [stellar population models] - line indices + [stellar population models] Extended thick disks are uniformly old and metal poor compared to thin disk. Limitations: 1- age metallicity degeneracy 2- calibration Dalcanton et al 2002, Zibetti et al 02

Formation history of other galaxies: Beyond…:coarse information Evidence: integrated light: “z” + bulk kinematics - broad-band colors + [stellar population models] red= old/metal rich blue= young/metal poor - low resolution spectra (>2Å, R<2000) line indices + stellar population models (Lick, Rose: Worthey et al, Trager et al, Tripico & Bell, Rose et al)

Formation history of other galaxies: Worthy 1998 Age Z blue Beyond: integrated light of **GCs** low resolution spectra (>2Å) + stellar population models Limitations: 1- Age/metallicity degenerate (young/z-rich  old/z-poor) 2- accuracy: [Fe/H]: ± few/10 dex (?) z vs Fe ? Mg, O,Ca…? calibration? fiducial populations? * SINGLE generations of star formation.

Formation history of other galaxies: Worthy 1998 Age Z blue Beyond: integrated light of *GCs* low resolution spectra (>2Å) + stellar population models Limitations: 1- Age/metallicity degenerate (young/z-rich  old/z-poor) 2- coarse: [Fe/H]: ± few/10 dex 3- z vs Fe ? Mg, O,Ca…? 4- calibration? abundance of fiducial populations? O,Mg,Ca vs Fe * SINGLE* generations of star formation.