n-body/sph simulations of galactic disks · 2010-07-13 · rok roškar, sarah loebman fabio...
TRANSCRIPT
![Page 1: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/1.jpg)
N-body/SPH Simulationsof Galactic Disks
Thomas Quinn, University of Washington
![Page 2: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/2.jpg)
Greg Stinson, Charlotte Christensen, Alyson BrooksRok Roškar, Sarah Loebman
Fabio Governato, Chris Brook, Victor Debattista,
James Wadsley
![Page 3: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/3.jpg)
A short history of the Universe:
● The Big Bang
● Quantum era: the large structures we see today started as quantum froth
● Universe becomes transparent
● First stars form
● Galaxies form
● Much later: Sun and planets form
![Page 4: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/4.jpg)
Image courtesy NASA/WMAP
![Page 5: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/5.jpg)
What is the Universe made of?
● Mostly not baryons
● Simulations show: not known neutrinos
● DM Candidates:
– Sterile Neutrinos
– Axions
– Lightest SUSY Particle (LSP)
![Page 6: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/6.jpg)
Evidence for Dark Matter
● Motions of Galaxies in Clusters
● <v2> ~ GM/R
● Mtotal
>> Mstars
![Page 7: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/7.jpg)
Image courtesy NASA/WMAP
Galaxy Formation: How does this ...
![Page 8: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/8.jpg)
... turn into this?
![Page 9: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/9.jpg)
Computational Cosmology
● CMB has fluctuations of 1e-5● Galaxies are overdense by 1e7● It happens (mostly) through
Gravitational Collapse● Making testable predictions from a
cosmological hypothesis requires– Non-linear, dynamic calculation– e.g. Computer simulation
![Page 10: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/10.jpg)
Cosmology and Galaxies
● CDM implies structure at all scales– Hierarchical Merging– Substructure
● Angular momentum from tidal torques– 10's of Mpc for a galaxy halo
● Accretion evolves with time● Galaxies form in a context
![Page 11: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/11.jpg)
Simulating Galaxy FormationRequirements:
● Full cosmological context with high resolution● Dynamic range of 100,000 in time and space● Treecode/SPH or similar adaptive method is
required.
● Physically motivated subgrid effects of star formation and feedback
● Complete simulations to present epoch.● Analyze with multiple simulated observations
![Page 12: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/12.jpg)
Simulation process● Start with fluctuations based on Dark Matter
properties● Follow model analytically (good enough to get
CMB)● Create a realization of these fluctuations in
particles.● Follow the motions of these particles as they
interact via gravity.● Compare final distribution of particles with
observed properties of galaxies.
![Page 13: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/13.jpg)
Simulating galaxies: Procedure
1. Simulate 100 Mpc volume at 10-100 kpc resolution
2. Pick candidate galaxies for further study
3. Resimulate galaxies with same large scale structure but with higher resolution, and lower resolution in the rest of the computational volume.
4. At higher resolutions, include gas physics and star formation.
![Page 14: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/14.jpg)
Gas Stars
Dark Matter
![Page 15: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/15.jpg)
Effect of Increasing Resolution on the size of disksEffect of Increasing Resolution on the size of disks
![Page 16: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/16.jpg)
Star Formation/Feedbackimplemented in GASOLINE (Wadsley et al 2004)
Gas
SFThreshold
Stars
< 8 MsunMetals
Blast WaveNo Cooling
> 8 Msun
Dynamical timeSF efficiency
Kroupa IMFPadova lifetimes
Winds
SN II
SN Ia
Stinson et al 2006
![Page 17: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/17.jpg)
Effects of Feedback on MorphologyEffects of Feedback on Morphology
![Page 18: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/18.jpg)
Simulation successes
In Large Disk galaxies:● Number and luminosity of MW satellites● Star formation history vs. mass (downsizing)● Galaxy Luminosity vs. Mass (Tully-Fisher)● Disk scale length● Mass-Metallicity relation
![Page 19: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/19.jpg)
Cosmological Disks Summary:
Tested the CDM Galaxy Formation Model over a wide range of Observational
Constraints.
Governato et al 07Data from Giavanelli
![Page 20: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/20.jpg)
The Astronomer’s Periodic Table
H He
Metals
![Page 21: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/21.jpg)
The Mass-Metallicity Relationship for Galaxies
Stellar Mass (M∕ )
12+
log(
O/H
)
Brooks et al. (2007)Tremonti et al. (2004)
Erb et al. (2006)
MZR
![Page 22: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/22.jpg)
Dwarf galaxies: CDM's hurdle
● Substructure problem● Core/cusp problem● Angular momentum problem● Bulge/Disk ratio● Can Baryon/Disk physics solve these?
![Page 23: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/23.jpg)
The CDM Substructure Problem
Moore et al 1998
![Page 24: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/24.jpg)
Core/Cusps in Dwarfs
Moore 1994
![Page 25: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/25.jpg)
Angular momentum Problem
Van den Bosch 01Bullock 01Too few low-J baryons
![Page 26: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/26.jpg)
Bulge/Disk ratioDutton 08
● Disk dominated● Sersic n ~ 1● Blue: g – r < 0.6
![Page 27: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/27.jpg)
Dwarf simulated to z=0
Stellar mass = 5e8 Msun`
Mi = -16.8
g - r = 0.53V
rot = 55 km/s
Rd = 1 kpc
MHI/M
* = 2.5
fb = .3 f
b cosmic
i band image
![Page 28: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/28.jpg)
![Page 29: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/29.jpg)
Dwarf Galaxy Properties
● Bursty SF● Holes in HI● HI turbulence 5-10
km/s● Rising rotation
curve● Low specific SF
rate● Low baryon
fraction
![Page 30: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/30.jpg)
Dwarf Galaxy Properties
● Bursty SF● Holes in HI● HI turbulence 5-10
km/s● Rising rotation
curve● Low specific SF
rate● Low baryon
fraction
![Page 31: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/31.jpg)
Dwarf Galaxy Properties
● Bursty SF● Holes in HI● HI turbulence 5-10
km/s● Rising rotation
curve● Low specific SF
rate● Low baryon
fraction
![Page 32: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/32.jpg)
Dwarf Galaxy Properties
● Bursty SF● Holes in HI● HI turbulence 5-10
km/s● Rising rotation
curve● Low specific SF
rate● Low baryon
fraction
![Page 33: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/33.jpg)
Dwarf Light Profile
![Page 34: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/34.jpg)
Rotation Curve
![Page 35: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/35.jpg)
Angular Momentum
Outflows preferential remove low J baryons
![Page 36: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/36.jpg)
Resolution effects
Low resolution: badLow resolution star formation: worse
![Page 37: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/37.jpg)
Simulation Issues
● Resolution: Large particle number/high force resolution
● Understanding star formation/feedback● Resolution: H2 regions need to be
resolved● Understanding ISM physics● Resolution● Constraining formation scenarios with
Stellar Kinematics● Resolution
![Page 38: N-body/SPH Simulations of Galactic Disks · 2010-07-13 · Rok Roškar, Sarah Loebman Fabio Governato, Chris Brook, Victor Debattista, ... 1. Simulate 100 Mpc volume at 10-100 kpc](https://reader034.vdocuments.site/reader034/viewer/2022042417/5f331396e6bf0278f708ae86/html5/thumbnails/38.jpg)
Aquila project
● Comparison of a Milky Way size galaxy● Range of Resolutions● Variety of codes
– Models of subgrid physics● Hybrid particles● No subgrid model
– Hydrodynamic algorithms● SPH/Moving Mesh/Eulerian