1. By : Sydney Duncan Advisor: Dr. Ferah Munshi 7/30/2015
40 Thieves: An Extremely High Resolution Simulation of Dwarf Galaxies
By : Sydney Duncan
Advisor: Dr. Ferah Munshi
7/30/2015
R Jay Gabany (Blackbird Obs.), Insert: Subaru/Suprime-Cam (NAOJ), Collaboration: David Martinez-Delgado (MPIA, IAC), et al.

2. What is a Dwarf Galaxy?
Any galaxy with a total mass (baryons + DM) less than solar masses
Dwarf galaxies are dark matter dominated
Tend to be gas poor
Predicted to be abundant by Lambda cold dark matter (LCDM) predictions

3. What is an N-body + SPH Simulation?
Is a model of a dynamical system of particles under the influence of a force (gravity)
SPH= smoothed particle hydrodynamics
Particles of different masses represent certain things: gas, dark matter (DM), stars
Stars + DM interact in the N-body sense (under influence of gravity)
Gas modeled via hydrodynamics

4. 40 Thieves: Exceptionally High resolution
SPH resolution ~6 pc, Gravity resolution ~60 pc
7 “observable” halos, many more “dark” halos
Largest collection of dwarf galaxies in a single simulation at pc-level resolution
Unprecedented data set

5. Dwarf Galaxies tell us a lot about Dark Matter
LCDM predicts that all DM halos can be fit an NFW profile:

6. Is LCDM incorrect or is there another process that creates DM cores?
Question:
Is LCDM incorrect or is there another process that creates DM cores?
Can the same mechanism form stellar cores?

7. Supernova Feedback (SN)
SNe injects energy into star forming regions within the galaxy, creating gas outflows (and gas removal)
This rapid deposition of energy alters the orbits of DM and stars [adiabatic process]
pushes orbits outward
Central density of DM is decreased
Governato & Pontzen (2012), Pontzen & Governato (2012), Munshi+ (2013)

8. Rotation Curve

9. Stellar Density Profile

10. ∑ ∗ = 𝐴𝑒 − 1 𝑟 𝑐 𝑟
Exponential Fit
Munshi+ (2015), in prep

11. Stellar cores are consistent with DM cores
Conclusions
Stellar cores indicate that feedback acts upon stellar orbits like on DM orbits
Stellar cores are consistent with DM cores

12. Future Work Comparison with observational data
Further our understanding of SNe as a function of halo mass
Guide predictions for DM direct detection experiments
F.Governato et al 2012

13. References Governato et al. 2009 Governato et al. 2012
Madau et al. 2014
Munshi et al. 2013
Shen et al. 2014