Chemical Evolution of Dwarf Spheroidals
I want to understand the evolution of dwarf galaxies
in the Local Group. My main focus is on the recently discovered
ultra-faint dwarf galaxies, which range in luminosity from ~ 1000
L
sun to less than 100,000 L
sun. In order
to understand the evolution of these systems, chemical abundances
are needed to constrain the star formation efficiency and
environmental effects on the internal evolution of each galaxy.
The ultra-faint dwarfs are also laboratories for proving chemical
enrichment models from supernovae at very low metallicities. They
are possible candidates for enrichment from one or few supernovae,
thus making them promising sites for observationally testing
predictions for supernovae elemental yields.
Together with
Marla Geha
and
Evan Kirby, I am
approaching these questions using medium-resolution spectroscopy,
in order to obtain large chemical abundance samples that will allow
us constrain chemical abundance patterns robustly.
In general, I am also interested in any type of galaxies
of Local Group galaxies,
This includes classical dSphs in the
Milky Way, the Andromeda dwarf system, globular clusters, and so on.
Chemical Abundances of Milky Way Halo Stars
In collaboration with
Wako Aoki, I have measured chemical abundances a sample
of metal-poor RGB stars in the Milky Way halo, using high S\/N
Subaru/HDS spectroscopy, which share similar stellar parameters
as red giants observed in the dSphs (with high-resolution spectrography).
I began this project while participating in the East-Asia and Pacific
Fellowship Program, co-funded by the NSF and the Japan Society
for the Promotion of Science.
Search for Ultra-Faint Dwarf Galaxies in SDSS III
SDSS has been pivotal in the discovery of ultra-faint
dwarf galaxies around the Milky Way, owing to its large
spatial coverage of more than 10,000 square degrees
As part of my first-year project at Yale,
I worked with
Marla Geha
to search for faint substructures in the SDSS/SDSS3 footprint,
producing a list of candidate objects. I also learned more
about various data filtering techniques in the process.
See
here for
poster abstract.
Other Projects
Dynamical Heating of Intra Cluster Medium
Advisor: D. Nagai (Yale)
Dark matter substructure is continuously being deposited into
galaxy clusters due to the hierarchical nature of structure formation.
I am investigating whether infalling dark matter clumps heat the ICM
via dynamical friction, using galaxy cluster simulations with the AMR
code CART.
Undergraduate Research: Calibration of Stromgren Photometry
I spent most of my undergraduate years working on the
uvbyHβ
photometric system, focusing on metal-rich G and K dwarfs. During my time
at the (
SDSU REU),
I used the Mount Laguna 24-inch and 40-inch telescopes to enlarge the
available sample of Stromgren photometry of such stars. I also studied
how metallicity affects Stromgren indices, using synthetic spectral libraries.
See
here for the paper, part of which is
based on my work.