ADS Author Query

Dwarf galaxy formation and evolution in a cosmological framework
Dr. Anatoly Klypin, NMSU and Sebastian Trujillo-Gomez, University of Zurich

My main research interest is exploring galaxy evolution in a cosmological context. Thanks to funding from the Blue Waters Graduate Fellowship, I am currently examining how dwarf galaxies form and evolve both in isolation and around massive (Milky Way like) galaxies.

In order to examine dwarf galaxy evolution, I use the hydrodynamical simulation code hydroART. This is an adaptive mesh code that obtains higher resolution in high gas density regions. Galaxy formation is extremely complex, requiring a huge range of scales and many poorly understood physical phenomena. It is our goal to create simulated galaxies that include physically motivated prescriptions for star formation and feedback at high resolution (<30 of pc) within a cosmological framework. This is by no means a simple task, but we are working to have our code approximate the processes of the Universe as closely as possible.

Our group uses the hydroART code to create cosmological zoom-in simulations. I am currently actively improving/developing aspects of the code including optimizing routines, implementing MPI parallelization, and improving physical processes included in the code such as direct radiation pressure and HII region pressure from young, massive stars.

Blue Waters is a Cray XE/XK supercomputer capable of sustained petascale computing. It has over 26,000 compute nodes and ~1.4 PB of system memory. The Blue Waters system is will significantly advance my research project by allowing me to simulate a large number of isolated dwarf galaxies at high spacial and temporal resolution. This is impossible to do on smaller computing systems as the memory, CPU, and storage needs exceed that of smaller compute clusters. Blue Waters will allow a deeper understand of dwarf galaxy evolution through the creation of this large sample of simulations.

Previous Research Projects

Effects of baryon removal and tidal stripping on the structure of dwarf spheroidal galaxies
Dr. Anatoly Klypin, NMSU and Surhud More, WPI
Arraki, Kenza S.,Klypin, A., More, S., Trujillo-Gomez, S., 2014, MNRAS, 438, 1466

We explored how the inclusion of baryons changes the results of collisionless cosmological simulations on small (satellite galaxy) scales. To do this we ran numerical simulations comparing a "pure" N-body simulation to ones including baryonic effects. We found that the removal of baryons in the satellite galaxy, combined with the addition of a baryon disk component in the host galaxy alleviates some small scale CDM concerns. Dwarfs that were extremely massive in collisionless simulations ("massive failure" or "too big to fail galaxies" in Boylan-Kolchin et al. 2011, 2012) have their circular velocity profiles reduced after including baryon effects, so that they agree with Local Group dSphs.

Predicting tidal stripping of satellite galaxies
Dr. Anatoly Klypin, NMSU

In this project we created predictive models for the tidal stripping of subhalos orbiting a MW including a disk. This was done using N-body simulations for satellites with a wide range of orbits and halo masses. We found that the tidal radius over scale radius value is most important in determining the amount of mass loss and structural changes to a satellite galaxy.