Calibrating the role of TP-AGB stars in the cosmic matter cycle Paola Marigo Department of Physics and Astronomy G. Galilei University of Padova, Italy Why Galaxies Care about AGB Stars III. University of Vienna July 29, 2014
OUTLINE 1. The TP-AGB star conundrum in galaxy models up to high redshift. 2. The need for a physically sound calibration of the TP-AGB over the age-metallicity plane. 3. Magellanic Cloud clusters as classical calibrators and insidious problems. 4. Magellanic Cloud clusters as novel and more powerful calibration tools. 5. Moving beyond the MC clusters: excellent quality data for resolved AGB are available to be fully exploited! 6. A few steps along calibration cycle.
(I. Cherchneff s talk ) (O. Straniero s talk ) Adapted from M. Marengo (2000) (S. Höfner s talk )
Color-magnitude diagrams: Spitzer SAGE of the LMC Spectral energy distributions: post star-burst galaxies at high z Stellar spectra: visual and IR Stellar atmospheres Nearby resolved galaxies Distant unresolved galaxies The TP-AGB evolution affects the spectrophotometric properties of galaxies up to high redshift.
AN EXAMPLE OF COMPLEX, WELL UNDERSTOOD, PHYSICS IN AGB STARS MOLECULAR CHEMISTRY AESOPUS code (Marigo & Aringer 2009) on the fly in TP-AGB models OPACITY POPULATION EFFECTS EVOLUTIONARY EFFECTS Marigo et al. 2013, MNRAS, 434, 488 22/10/2012 Core He-burn + RGB +E-AGB O-rich TP-AGB stars C-stars Milky Way disk Milky Way Halo
An example of unsatisfactory treatment of the TP- AGB phase: EPS models for high redshift galaxies Composite spectral energy distribution of 64 post-starburst galaxies with 0.7 z 2.0 Kriek et al. 2010, ApJ, 722, L64 SED fitting with population synthesis models yields galaxies masses and ages. The modelling of TP-AGB stars is critical!
Discrepancy by a factor 2-3 in galaxy mass and age among current EPS models MASS AGE 29/10/2012
TP-AGB uncertainties propagate further? Heavy TP-AGB Light TP-AGB Based on the Millennium Cosmological Simulation Courtesy S. Charlot
We need to calibrate the contribution of TP-AGB stars over the age-metallicity plane Nuclear fuel L(t)dd = integrated light No carbon stars at old ages and high metallicity What are the precise limits? How efficient is the third dredge-up? What is the minimum mass for the onset of hot-bottom burning? TP-AGB is maximum at ages 10 9 yr What is the exact peak amplitude? How does it depend on metallicity? How long is the TP-AGB lifetime (Mi,Zi)? What is the rate of mass (gas and dust) injection from AGB stars?
I. MAGELLANIC CLOUD CLUSTERS AS CLASSICAL TP- AGB CALIBRATORS: Pioneer work Frogel, Mould & Blanco 1990 Fuel Consumption Method AGB luminosities nuclear fuel Stellar Isochrone Method AGB star counts lifetimes Integrated colors Maraston 1998, 2005 Girardi & Marigo 2007 Noel et al. 2013
TP-AGB calibrations on MC clusters seem not to work well for other external galaxies EPS model based on Maraston 2005 TP- AGB models overestimate the SEDs in the IR of high-z post star-burst galaxies (Kriek et al 2013, Zibetti et al. 2013) Nearby dwarf galaxies with HST : Marigo & Girardi 2007 TP-AGB models show an average excess: 40% in the AGB star counts factor of 2 in the integrated near-ir flux RGB + AGB stars responsible for 21% + 17% of the integrated flux emitted by galaxies in the near IR (Melbourne et al. 2012, ApJ, 748, 47)
Girardi et al. 2013, ApJ, 777, 142 The peak of TP-AGB contribution has been likely overestimated due to an AGB boosting effect at ages 1.6 Gyr (M TO 1.7 M ) Fuel Consumption Method AGB luminosities nuclear fuel Stellar Isochrone Method AGB star counts lifetimes Integrated colors Maraston 1998, 2005 Girardi & Marigo 2007 Noel, Greggio, Renzini, et al. 2013
The insidious TP-AGB boosting Reason: abrupt change in core He-burning lifetimes close to the critical mass M HeF (degenerate/non degenerate He cores) Girardi et al. 2013, ApJ, 777, 142
The insidious TP-AGB boosting A triple TP-AGB develops at an age of 1.65 Gyr! Reason: abrupt change in core He-burning lifetimes close to the ciritical mass M HeF (degenerate/non degenerate He cores) Girardi et al. 2013, ApJ, 777, 142
The insidious TP-AGB boosting Reason: abrupt change in core He-burning lifetimes close to the ciritical mass M HeF (degenerate/non degenerate He cores) SSP integrated luminosity Age distribution of TP-AGB stars in MC clusters boosting period boosting period Girardi et al. 2013, ApJ, 777, 142
The insidious TP-AGB boosting Reason: abrupt change in core He-burning lifetimes close to the ciritical mass M HeF (degenerate/non degenerate He cores) Previous calibrations biased towards too heavy TP-AGB. Revision of MC clusters urgently needed! SSP integrated luminosity Age distribution of TP-AGB stars in MC clusters boosting period boosting period Girardi et al. 2013, ApJ, 777, 142 L SSS t = L M i φ M i dm i t=ccccc.
II. Beyond the classical calibration on MC clusters: H-R diagrams+abundances+variability+mass loss Kamath et al. 2012, ApJ, 746, 20 Lebzelter & Wood 2007 NGC 419 NGC 1978 NGC 1846 P 2 P 1 P 0 P 2 P 1 P 0 Kamath et al. 2010, MNRAS 408,522 Lebzelter et al. 2008, A&A, 486,511 Lederer et al. 2009
AGB stars in MC clusters: constraints on nucleosynthesis and mixing (M,Z) Envelope overshooting & Intershell composition depth of the partially-mixed zone Efficiency of the 3 rd dredge-up Minimum core mass for the 3 rd dredge-up Kamath et al. 2012, ApJ, 746, 20
III. BEYOND THE MC CLUSTERS: wide age-metallicity sampling and characterization The Milky Way Bulge The Panchromatic Hubble Andromeda Treasury Disk population Near solar metallicity 2MASS,OGLE,WISE super-solar metallicity, old ages The Magellanic Clouds The ACS Nearby Galaxy Survey Treasury Local Group dwarf galaxies Fields and clusters 2MASS, VISTA, Spitzer, OGLE 62 dwarf galaxies d < 4 Mpc All metallicities down to very low
III. BEYOND THE MC CLUSTERS: wide age-metallicity sampling and characterization The Milky Way Bulge The Panchromatic Hubble Andromeda Treasury Disk population Near solar metallicity 2MASS,OGLE,WISE super-solar metallicity, old ages The Magellanic Clouds The ACS Nearby Galaxy Survey Treasury Local Group dwarf galaxies Fields and clusters 2MASS, VISTA, Spitzer, OGLE 62 dwarf galaxies d < 4 Mpc All metallicities down to very low
III. BEYOND THE MC CLUSTERS: wide age-metallicity sampling and characterization The Milky Way Bulge The Panchromatic Hubble Andromeda Treasury Disk population Near solar metallicity 2MASS,OGLE, WISE super-solar metallicity, old ages TP-AGB OBSERVABLES Optical, near-mid IR photometry Spectral classification Long-period variability (OGLE) Mass-loss rates, wind velocities, dust chemistry (Spitzer, ALMA) Chemical abundances Initial-final mass relation Stelllar parameters from interferometry The ACS Nearby Galaxy Survey Treasury The Magellanic Clouds 62 dwarf galaxies d < 4 Mpc All metallicities down to very low Local Group dwarf galaxies Fields and clusters 2MASS, VISTA, Spitzer, OGLE
I. TP-AGB lifetimes to more recent ones Weiss & Ferguson 2009 Renzini & Voli 1981 Groenewegen & de Jong 1993 Mohucine & Lançon 2002 Marigo & Girardi 2007 Karakas et al. 2002 Z=0.008 Marigo et al. 2013 from older TP-AGB models
I.TP-AGB lifetimes: probing the low-metallicity low-mass regime more details in Rosenfield s talk The ACS Nearby Galaxy Survey Treasury AGB star counts & luminosity functions Rosenfield et al. 2014, ApJ, TP-AGB TP-AGB lifetimes 62 dwarf galaxies d < 4 Mpc All metallicities down to very low At low metallicities: Short TP-AGB lifetimes at older ages τ 1Myr for M i 1 M Metallicity dependence: Z τ
Different stages of mass loss pulsation-assisted dust-driven winds plot from Straniero et al. 2006 Before the onset of large-amplitude pulsation stellar winds in giants driven by other mechanisms, e.g. flux of Alfvén wave energy associated to cool chromospheres (W. Vlemmings talk )
Different stages of mass loss pulsation-assisted dust-driven winds plot from Straniero et al. 2006 Before the onset of large-amplitude pulsation stellar winds in giants driven by other mechanisms, e.g. flux of Alfvén wave energy associated to cool chromospheres (W. Vlemmings talk ) Novel theoretical efforts: Cranmer & Saar 2011, ApJ, 741, 54 Magnetohydrodynamic turbolence in the convective subsurface zones dm/dt (F A* ) 12/7, steep scaling with the magnetic energy flux efficient pre-dust mass loss in low-metallicity low-mass TP-AGB stars compared to classical Reimers 1975 and Schröder & Cuntz 2005
II. The core mass growth: the initial-final mass relation 66 white dwarfs, most in open clusters Extension to the low-mass end: CPMPs Catalan et al. 2008 old open clusters Kalirai et al. 2008 change of slope at M i 4 M Large scatter hetereogeneous sources, various metallicities. Uncertainties due to WD models and stellar evolution M WD and t cooling: spectral fitting (Teff and g) + grid of WD models and theoretical M-R relation M i : τ M i = τ cluster t cooling (WD) Age and metallicity of clusters overshooting Thickness of the WD H/He layers Composition of the WD core (He, C-O, O-Ne)
II. The core mass growth depends on: a) efficiency of mass loss Pulsation-assisted dust-driven wind Superwind PN ejection exponential increase Figure adapted from Straniero et al. 2006
II. The core mass growth depends on: b) efficiency of the third dredge-up Reduction of the core mass O.Pols 2 M, Z=0.02 The efficiency λ = Δm du Δm H is poorly known from theory General trend: the third dredge-up goes deeper at M and Z
Differences among different models, getting smaller in more recent calculations Larger final masses at lower Z, (despite more efficient dredgeup) due to larger M c,1tp Bressan et al. 2012
Accurate and homogeneous IFMR data can constrain mass loss and third dredge-up 18 high S/N white dwarfs, homogeneous analysis, all clusters sharing Z =0.02 ([Fe/H]=+0.1) NGC6819 NGC7789 Hyades Praesepe M c,1tp Kalirai et al. 2014, ApJ, 782, 17
Bracketing mass loss and third dredge-up No dredge-up (λ=0) Reimers 1975 Bedjin 1988 Vassiliadis & Wood 1993 Van Loon et al. 2005 Blöcker 1995 deep dredge-up The stronger the mass loss, the weaker the effect of the third dredge-up
Calibrating mass loss, 3 rd dredge-up, lifetimes Z=0.02 mass-loss 3 rd dredge-up Kalirai et al. 2014, ApJ, 782, 17 Inefficient C-star formation, see also poster S5-01 (Boyer et al.) TP-AGB lifetimes
CURRENT STATE OF THE CALIBRATION (ongoing) ANGST calibration new IFMR data
CURRENT STATE OF THE CALIBRATION (ongoing) ANGST calibration new IFMR data
CURRENT STATE OF THE CALIBRATION (ongoing) ANGST data new IFMR data The island of AGB stars: solar and MC metallicites and intermediate ages 11 9 yy
Take away Classical calibration on MC clusters: TP-AGB likely overestimated due to a boosting at ages aroung 1.7 Gyr. Complete revision needed. Novel and extensive calibration on MC clusters: wealth of additional information (long-period variability, chemical abundances, mass loss). Good constraints of the TP-AGB core mass growth and fuel: accurate and homogeneous initial-final mass relation data. Calibration beyond the MC clusters: unprecedented high-quality data in other nearby galaxies to probe unexplored regions of the age-metallicity plane (very low-and supersolar metallicities). The «island» of TP-AGB stars: stronger TP-AGB contribution at intermediate ages ( 1 Gyr) and MC solar metallicities (ongoing calibration). This research is supported under ERC Consolidator Grant funding scheme (project STARKEY) Why Galaxies Care about AGB Stars III. University of Vienna July 29, 2014
Emitted light by a TP-AGB star core mass growth + chemical yields mass fraction primary He, C, N, O chemical yields core mass growth 1 st thermal pulse AGB-tip time E TT AAA = l t dd F TT AAA X + 0. 11 M AAAA c M 111 c + F Y HH + τ AAA F Y C, N, O Marigo & Girardi 2002
Emitted light by a TP-AGB star core mass growth + chemical yields mass fraction primary He, C, N, O chemical yields EMITTED LIGHT & CHEMICAL ENRICHMENT ARE COUPLED! core mass growth 1 st thermal pulse AGB-tip time E TT AAA = l t dd F TT AAA X + 0. 11 M AAAA c M 111 c + F Y HH + τ AAA F Y C, N, O Marigo & Girardi 2002
A hybrid approach: The COLIBRI code Marigo et al. 2013, MNRAS, 434, 488 It optimizes the ratio pppppppp aaaaaaaa ccccccccccccc iiiiii Initial conditions at the 1 st TP from Parsec tracks (Bressan et al. 2012) Integrations of the 4 stucture equations from the atmosphere down to the bottom of the H- burning shell. Sperically symmetric atmosphere Hot-bottom burning : pp chains, CNO cycle, NeNa, MgAl cycles, Cameron-Fowler Beryllium transport mechanism for 7 Li production. Nuclear network coupled to a diffusive approximation of convection. PDCZ nucleosynthesis Ausiliary analytic formalism from Wagenhuber & Groenewegen 1998, Karakas et al. 2002, Bressan et al. 2012
TP-AGB nucleosynthesis and molecular chemistry Convective envelope abundances Photospheric molecular concentrations AESOPUS on-the-fly log log M i =5 Msun Z=0.008
An efficient tool: ÆSOPUS Accurate Equation of State and OPacity Utility Software Marigo & Aringer 2009, A&A, 508, 1539 Rosseland mean opacites on demand for arbitrary chemical mixtures Web-interface: http://stev.oapd.inaf.it/aesopus Æsopi fabula: De sole et vento Illustra tion by Francis Ba rlo w, 1687 Uncomparably fast performance: 1 opacity table computed in real time and ready in < 40 s Full freedom in setting the abundances of atoms from H to U
ÆSOPUS CHEMISTRY The EOS under instantaneous equilibrium assumption solved for the concentrations of 800 species: 300 atoms and ions + 500 molecules Z=0.02 Z=0
ÆSOPUS opacity H and He: continuum true absorption, scattering, line transitions, collision-induced absorption heavier elements: atoms (Opacity Project database), molecules (line lists: HITRAN and other sources, optimized opacity sampling) 22.07.2013
ÆSOPUS suitable for AGB star models Marigo & Aringer 2009, A&A, 508, 1539 WEB interface http://stev.oapd.inaf.it/aesopus C/O < 1 C/O > 1 Workshop del Dipartimento di Fisica e Astronomia G.Galilei 22/10/2012