Chemodynamical Simulations Of the Universe & Elliptical Galaxies. Chiaki Kobayashi (Stromlo Fellow, RSAA, ANU)

Transcription

1 Chemodynamical Simulations Of the Universe & Elliptical Galaxies Chiaki Kobayashi (Stromlo Fellow, RSAA, ANU)

2 Chemodynamical Evolution AGN (negative & positive) Feedback? Gravity Hydrodynamics Star Formation? Feedback? Galaxy-AGN Co-Evolution? Whatʼs the seed? Primordial? Stars? How to fuel? Loss of Angular Momentum?

3 Chemodynamical Evolution MC H,He 10 9 yr? Gravity Hydrodynamics Star Formation? Feedback? yr ISM O,Mg,(Fe) thermonuclear explosion core collapse in WD binaries? of massive stars SN II HN ISM Fe SN Ia HN: Hypernova, Iʼll explain in 5min

4 Cosmological Simulation Animations are: Stellar Luminosity Gas Metallicity 10Mpc; N~ ; m gas ~10 7 M ; H 0 =70, Ω m =0.3, Ω λ =0.7, Ω b =0.04, n=1, σ 8 =0.9

5 Cosmic SFR vs Stellar Density Evolution UV: Lilly+ 95, Connolly+ 97, Madau+ 98, Steidel+ 99, Bouwens+ 03, Giavalisco+ 04, Ouchi+ 04, Iwata+ 03, Bunker+ 04, Schiminovich+ 05, H!: Gallego+ 95, Perez-Gonzalez+ 03, Gronwall 99, Brinchmann+ 04, Tresse & Maddoz 98, Tresse+ 02, X-ray: Norman+ 04, radio: Barger+ 00, Submilli: Hughes+ 98. Present Stellar Fraction No FB: 24% SN FB: 15% HN FB: 8% obs: 6% (Fukugita & Peebles04) With dust correction Fraction of stars formed at... M*>10 8 M All Stars CK, Springel, White 2007

6 Galactic Winds Mass-Metallicity Relation Wind Fraction dots: simulation, lines: observation Origin of the mass-metallicity relation? --- mass-dependent galactic winds. CK, Springel, White 2007

7 Chemodynamical Model

8 GRB Hypernovae SN Light Curve & Spectra bright, broad, blended line E>10 52 erg,m(fe)>0.1m (Iwamoto et al. 1998; Maeda & Nomoto 2003) SN1998bw

9 GRB Hypernovae SN Light Curve & Spectra bright, broad, blended line E>10 52 erg,m(fe)>0.1m HN efficiency=0.5 for M>20 SN1998bw Nomoto et al. 2002

10 Chemical Evolution in our Galaxy

11 Chemodynamical Model Kinematics of DM, gas, star particles Hydrodynamics: (1)GRAPE-SPH code (Kobayashi 04) (2)Parallel Tree-SPH code Gadget-2 (V.Springel et al. 2001, Springel 05) Dρ Dt + ρ v = 0 Dv Dt = 1 P Φ ρ Du Dt = P Dρ ρ 2 Dt + (κ T) + Γ Λ ρ ρ 2 Φ = 4πGρ ρ i = m j W (r i r j ;h) Dv i Dt DA i Dt SPH method P = m j f i i 2 ρ W (h ) + f P j i ij i j 2 i ρ W (h ) i ij j m Π W j ij i j ij = 1 γ 1 2 ρ m Π v γ 1 γ 1 j ij ij iw ij + γ ( Γ Λ) i ρ i Computing: (1)GRAPE (2)Linux IBM p-series Supercomputer Regatta

12 Physical Processes UV background radiation (Haardt & Madau 1996) E Fe O BH,NS,WD Fe E O O Fe E P=1-exp(-Δt/t sf ) Cooling: Z-dependent Λ (Sutherland & Dopita 93) E Star Formation (1) v<0 (2) tcool<tdyn (3) tdyn<tsound Schmidt SFR t sf =t dyn /c, c=0.1 IMF with x=1.35 (1.10 for Es) Feedback 100% thermal to N FB ~400 E Fe E O SNIa SD:Kobayashi et al.1998 primary: 3-8M WD secondary: ~1-3M Z-effect: [Fe/H] > erg O Fe E yield (W7, Nomoto et al. 1997) SNII/HN 8-50M O Fe E E Stellar Wind 8-120M (Z/Z ) 0.8 erg ~ erg M,Z,E dependent yield (Kobayashi et al. 2006)

13 Elliptical Galaxies based on PhD thesis (2002)

14 Elliptical Galaxies Simulations of (dry/wet) major merger produce a galaxy that look like an elliptical galaxy (Toomre 72, Barnes 88, Hernquist, Burkert & Naab). M BH -M bulge relation, dynamical peculiarity (cores, shell, ripple, ), Morphology density relation, Merging rate, Color-Magnitude Relation, Passive Evolution, (1) Metallicity Radial Gradients? (e.g., Faber 1977; Davies, Sadler, Peletier 1993; Organo et al. 2005) (2) Scaling Relation? i.e., Fundamental Plane (e.g., Djorgovski & Davies 1987; Dressler et al. 1987, ) 2D Map with IFU (SAURON) Spectrum Fe5335 Counts Fe5270 H! Mg1 Mg2 Organo et al log!""å)

15 Animations are:

16 Simulated 100 Ellipticals Classify according to the merging history Monolithic-like Collapse Monolithic-like At z>3, assembly of subgalaxies with <10 9 M Monolithic Assembly At z>3, assembly of subgalaxies with ~10 10 M Assembly Submerger At z<3, merger with 1/10<mass ratio<1/5 Major Merger Major Merger At z<3, merger with mass ratio>1/5 Multiple Major Merger At z<3,major mergers more than twice Major Merger

17 Evolution of Radial Gradients Monolithic-like Collapse Major Merger Major Merger: flat metallicity gradients, larger radius Regeneration of gradients by the secondary star burst is included, but not enough.

18 Destruction of MG by Mergers (1) Destruction depending on mass ratio (major evolution) large mass ratio M 2 /M 1 shallower gradients (2) Regeneration due to the induced SF (but rare) large gas mass ratio strong SF@center not so much shallow (3) Weak evolution from minor mergers and/or gas accretion: large gas fraction of secondary weak SF@outer a little shallow Re-generation of metallicity Physical property of merging event vs. the change of metallicity gradient gradients :strong SF by induced, the :weak secondary SF induced mass ratio M 2 /M 1 gas fraction of gal2 gas mass ratio Mg 2 /Mg 1 star burst is automatically included, but not enough.

19 Metallicity Gradients - Mass observation Simulated Galaxies monolithic assembly submerger merger multiple mergers dwarfs Non-Major Merger: steep Major Merger: flat Distruction of the predent gradisnts Dry Merger Regeneration by secondary star burst is small Wet Merger (Kobayashi 2004, MNRAS, 347, 740)

20 Metallicity Gradients Non-Major Merger: steep! Major Merger: flat! (Kobayashi 2004, MNRAS, 347, 740)

21 Fundamental Plane σ 2 I e 2 / r e SB σ 2 / I e 2 / r e M/L 3D space of Velocity dispersion Surface brightness Effective Radius Simulated Galaxies monolithic assembly submerger merger multiple mergers dwarfs observations (Pahre 99) Merger larger r e, fainter SB e larger κ 3,smaller κ 2 σ 2 r e Mass (Kobayashi 2005, MNRAS, 361, 1216)

22 Deviation from Fundamental Plane dashed: dwarfs Non-Major Merger: smaller κ 3, Major Merger: larger κ 3 (Kobayashi 2005, MNRAS, 361, 1216)

23 Conclusions Cosmological Simulations with HN Feedback (half of M>20M ) HN-FB reduces cosmic SFR peaked at z~3-4. Present stellar fraction ~10%. Stars formed in dwarfs before they merge to massive galaxies. Stars are as old as ~10Gyr in giants, ~1-10Gyr in dwarfs. Galactic Winds blows more effectively from dwarfs. The origin of the mass-metallicity relation of galaxies. Chemical enrichment depends on the environment: At z~3, [O/H]~ -0.5 in LBGs, -1.5 in DLAs, -2 in IGM. GRAPE-SPH Simulations of Elliptical Galaxies Major Merger makes the metallicity gradient shallow, and induced SF is not enough to regenerate gradients. Major Merger makes the effective radius larger, which increases the scatter of the fundamental plane. Ellipticals form from successive merging of various (small, gasrich) galaxies under the CDM scenario. Major Merger is sufficient, not necessary. Future Work: AGN Feedback