1. On the initial conditions and evolution of isolated galaxy models 2012 Workshop on Computational Sciences and Research Hub Induck Hall at Pusan Nat'l University 2012. 07 12 ~ 14

2. Background  Cosmological hydrodynamic simulations  Observations indicate that spiral galaxies comprise five different components: → DM halo, stellar disk, stellar bulge, gaseous disk and gaseous halo. So far, however, ICs for almost all hydrodynamic simulations of galaxy (interactions) have considered only cold gas at the start of the simulation. Moster et al. (2011) included, for the first time, a diffuse rotating hot gaseous halo as well as the other four components and performed hydrodynamic simulations of mager mergers of disk galaxies.

3. Numerical Codes Galaxy Models Evolution Star formation histories of our models Contents

4. The Codes ICs (galaxy models) generated using the ZENO software package (version 008): - provided by Barnes - allows one to build multiple components in mutual equilibrium with user-specified density profiles in collisionless or gaseous form. Simulations performed using (an early version of) Gagdet3: - the Tree-SPH code developed by Springel - includes radiative cooling, star formation, SN feedback, a phenomenological model for galatic winds, and sub-resolution model of multiphase ISM (Springel & Hernquist 2003)

5. Galaxy models (Stellar) Bulge follows a Hernquist (1990) model & tapers at larger radii. Star and Gas Disks have an exponential radial profile & a sech 2 vertical profile. DM Halo follows a Navarro et al. (1996) model & tapers at larger radii. Gas Halo follows either the NFW or a non-singular isothermal profile.

6. Galaxy models Our primary goal: to study the effects of a hot gaseous halo on galaxy evolution Different types of our models: Type DH: 3 collisionless components + gas disk & gas halo Type DHi: Isothermal gas halo Type DHn: NFW gas halo Type D: 3 collisionless components + gas disk Type H: 3 collisionless components + gas halo In all our models: M tot =M b + M d + M h = 126 X 10 10 M ⊙ M b = 1 X 10 10 M ⊙ M d = M ds + M dg = 5 X 10 10 M ⊙ M h = M hd + M hg = 120 X 10 10 M ⊙

7. Galaxy models Model Parameters

8. Galaxy models Galaxy Models Wind Test Runs (including galactic winds)

9. Galaxy Models Model DHi (& DHir) at t=0

10. Galaxy Models Model DHi (& DHir) at t=0

11. Evolution of the Models 1. DHi 2. DHi-f5 3. DHir 4. DHn 5. DHn-f5 6. D 7. Hi

12. 1. Model DHi Gas halo: Isothermal, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384 Internal Energy vs Local Density t=0t=1 Gyrt=2 Gyr

13. 2. Model DHi-f5 Gas halo: Isothermal, f hg =0.05, M hg =6.0 X 10 10 M ⊙, N hg = 163840 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384 1. Model DHi Gas halo: Isothermal, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

15. 3. Model DHir Gas halo: Isothermal+Spin, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

16. 1. Model DHi Gas halo: Isothermal, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

17. 4. Model DHn Gas halo: NFW, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384 1. Model DHi Gas halo: Isothermal, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

18. 4. Model DHn Gas halo: NFW, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

20. 5. Model DHn-f5 Gas halo: NFW, f hg =0.05, M hg =6.0 X 10 10 M ⊙, N hg = 163840 Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

21. 7. Model Hi Gas halo: Isothermal, f hg =0.01, M hg =1.2 X 10 10 M ⊙, N hg = 32768 Gas disk: N/A 6. Model D Gas halo: N/A Gas disk: Exponential, f dg =0.12, M dg =0.6 X 10 10 M ⊙, N dg = 16384

22. Star Formation Rate vs Time

23. Summary * Models without a GH (type D): An increasing SFR at the beginning and then a continuously decreasing rate to the end * Models with a GH (type DH): More flat SFR than those without a GH * Models with an NFW GH (type DHn): Higher SFR than in those with an isothermal GH More gas accretion from the halo onto the disk * Models with a rotating GH: Lower SFR than in those with non-rotating GH