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The Prospect of Observing the KS Relation at High- z

Desika Narayanan Harvard-Smithsonian CfA. The Prospect of Observing the KS Relation at High- z. Chris Hayward. T.J. Cox . Lars Hernquist. Harvard. Carnegie. Harvard. Kennicutt-Schmidt SFR Laws. Locally: Bigiel 2008; Krumholz et al. 2009. Molecular Kennicutt-Schmidt SFR Laws.

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The Prospect of Observing the KS Relation at High- z

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  1. Desika Narayanan Harvard-Smithsonian CfA The Prospect of Observing the KS Relation at High-z Chris Hayward T.J. Cox Lars Hernquist Harvard Carnegie Harvard

  2. Kennicutt-Schmidt SFR Laws Locally: Bigiel 2008; Krumholz et al. 2009

  3. Molecular Kennicutt-Schmidt SFR Laws z~2: CO (J=3-2) Local: CO J=1-0 SFR Total H2 Gas Mass Gao & Solomon 2004 z~2 Bouché et al. 2007

  4. Prescriptions for multi-phase ISM (McKee-Ostriker) SF (volumetric Schmidt law) BH growth and associated Feedback Halos scaled to z~2 concentration For z~2 study, isolated galaxies Mbar ~ 1011 M, MMW disks SF follows SFR  1, 1.5, 2 Theoretical Approach: SPH simulations of galaxies Springel et al. (2003-2005)

  5. Non-LTE Radiative Transfer (Synthetic Molecular Line Emission) • 3D Monte Carlo code developed based on improved Bernes (1979) algorithm • Considers full statistical equilibrium with collisional and radiative processes • Sub-grid algorithm considering mass spectrum GMCs as SIS; Mcloud=104-106 M, (Blitz et al. 2006, Rosolowsky 2007, Bolatto et al. 2008) • Uniform Galactic CO Abundance, no H2 at NH < 1021 cm-2 DN+ 2006,2008 Desika Narayanan SFR@50, Spineto

  6. SUNRISE (dust RT) to ‘Select’ Galaxies Diffuse ISM GMC Physics Included in Monte Carlo IR RT: -IR transfer of stellar and AGN spectrum (starburst 99 for stars and Hopkins+ 07 for AGN) -dust radiative equilibrium -Kroupa IMF, ULIRG/SMG DTG (same as MW DTM) -Stellar Clusters surrounded by HII regions and PDRs (MAPPINGS; Groves et al. 2008) Jonsson, Groves & Cox (2009)

  7. Does Differential Excitation Matter?: Local Universe Example CO (J=1-0) CO (J=3-2) Index = 1.0 SFR ~ CO (3-2)0.9 SFR ~ CO (1-0)1.5 Narayanan et al. 2005 Iono et al. 2008 Gao & Solomon 2004

  8. Molecular Kennicutt-Schmidt SFR Laws CO J=1-0 HCN J=1-0 Index = 1.0 Index = 1.5 Gao & Solomon (2004) SF follows SFR  1.5

  9. Molecular Kennicutt-Schmidt SFR Laws CO (J=1-0) CO (J=3-2) Index = 1.0 SFR ~ CO (3-2)0.9 SFR ~ CO (1-0)1.5 Narayanan et al. 2005 Iono et al. 2008 Gao & Solomon 2004 SF follows SFR  1.5

  10. Differential Excitation; Underlying n=1.5 KS Index SFR-CO index SFR-HCN index CO (J=1-0) HCN (J=1-0) CO (J=3-2) Krumholz & Thompson 2007 Narayanan et al. 2008 SF follows SFR  1.5

  11. HCN (HCN (J=3-2) Observational Survey Bussmann, DN, Shirley, Wu, Juneau, Vanden Bout, Solomon et al. (2008)

  12. HCN (HCN (J=3-2) Observational Survey Bussmann, DN, Shirley, Juneau et al. 2008

  13. Getting to the KS Relation at z~2 SF follows SFR  1, 1.5, 2

  14. Getting to the KS Relation at z~2 SF follows SFR  1, 1.5, 2

  15. Getting to the KS Relation at z~2 SFR-LCO index versus Transition for KS = 2 galaxies SF follows SFR  1, 1.5, 2

  16. Mapping the CO 3-2 KS relation at z~2 to the underlying volumetric Schmidt Relation Physical KS index vs. SFR-CO (J=3-2) index Data from Tacconi et al. 2010: SFR ~ L(CO3-2)0.97

  17. Conclusions 1. Excitation Matters

  18. Conclusions 1. Excitation Matters 2. Getting the KS relation at high-z is feasible (now!)

  19. Prescriptions for multi-phase ISM (McKee-Ostriker), SF, BH growth and associated Feedback (though BH winds turned off) 100 galaxies used: 20 disk Galaxies 80 merger snapshots SF follows SFR  1.5 Assuming the free-fall time argument for SFR ~ 1.5 holds GADGET SPH Simulations Springel et al. (2003-2005), Desika Narayanan SFR@50, Spineto

  20. Can we Recover the Basic Relations? SFR-CO index SFR-HCN index HCN (J=1-0) CO (J=1-0) SFR ~ 1.5 (assumed Schmidt Law) SFR ~ Lmol (observed) Lmolecule ~  Then =1.5/ So we need to understand how line luminosity varies with gas density CO (J=3-2) SF follows SFR  1.5 Narayanan et al. 2008

  21. SFR ~ 1.5 (assumed Schmidt Law) SFR ~ Lmolecule (observed) Lmolecule ~ Then =1.5/ Fiducial Disk Galaxy V200=115 km/s fgas=0.2 CO (J=1-0) Narayanan et al. 2008

  22. SFR ~ 1.5 (assumed Schmidt Law) SFR ~ Lmolecule (observed) Lmolecule ~ Then =1.5/ Then =1.5/ Fiducial Disk Galaxy V200=115 km/s fgas=0.2 Low ncrit Increasing density will increase the gas mass, thus increasing the CO (1-0) luminosity proportionally Narayanan et al. 2008

  23. SFR ~ 1.5 (assumed Schmidt Law) SFR ~ Lmolecule (observed) Lmolecule ~  Then =1.5/ Then =1.5/ Fiducial Disk Galaxy V200=115 km/s fgas=0.2 High ncrit Narayanan et al. 2008

  24. SFR ~ 1.5 (assumed Schmidt Law) SFR ~ Lmolecule (observed) Lmolecule ~  Then =1.5/ Then =1.5/ Fiducial Disk Galaxy V200=115 km/s fgas=0.2 Increasing density will increase the gas mass, thus increasing the CO (1-0) luminosity proportionally <n> >> ncrit slope=1.5 <n> << ncrit slope < 1.5

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