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.

What is a Dwarf Galaxy? Any galaxy with a total mass (baryons + DM) less than 10 11 solar masses Dwarf galaxies are dark matter dominated Tend to be gas poor Predicted to be abundant by Lambda cold dark matter (LCDM) predictions

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

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

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

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?

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)

Rotation Curve

Stellar Density Profile

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

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

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

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