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Research
I am a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics. For a list of publications go here (ADS), or click here for my Curriculum Vita.
My primary research interest is understanding the formation of nuclear
star clusters and their relation to black holes. Nuclear star
clusters are found at the centers of most galaxies and are the most
massive and dense stellar collections in the universe.
I've
worked on a number of projects related to nuclear star clusters:
- Do Black Holes and Nuclear Star Clusters Co-exist? In a paper from
2008, we have shown that nuclear star clusters and black holes (as
indicated by AGN) co-exist in all types of galaxies over a signficant
range in mass.
- How do Nuclear Star Clusters Form? Using observations of
nearby edge-on spiral galaxies with HST, we found
that these clusters are flattened in the plane of their host galaxy
and have complex morphology and stellar populations, with younger
disks of stars embedded in an older spheroid stars (basically
self-similar to the larger galaxy structure!). These observations
suggest that nuclear star clusters form from accretion of material
(gas or star clusters) from their host galaxy disks.
- What can we learn from the nearest nuclear star clusters?
New adaptive optics technology allows us to study the kinematics of
the nearest nuclear star clusters in great detail. Using a wide
variety of telescopes, including adaptive optics corrected spectra
from the Gemini telescope, I have embarked on a study of the nearest
nuclear star. I've published the
first of our targets last year which shows clear rotation.
Detailed analysis of these observations combined with theoretical
modeling will allow us to understand the details of the nuclear star
cluster formation process and enable dynamical detection of any black
holes within the nuclear star clusters.
I've also worked on a number of other projects studying galaxy evolution
through stellar populations and stellar clusters in late-type (spiral
and irregular) galaxies. These include:
- For my PhD thesis, I analyzed the stellar populations of nearby
edge-on galaxies with Julianne Dalcanton and Roelof de Jong. This
work is published in two papers in the
Astronomical Journal. Pretty pictures of the galaxies can be seen here.
- I'm a part of two large Hubble Space Telescope projects focused
on studying the resolved stars in nearby galaxies. The ANGST collaboration has used
HST to image galaxies between 1-4 Mpc to determine their star
formation histories. GHOSTS has focused
on the stellar halos of nearby galaxies; studying the tenuous outer
parts of galaxies can reveal their earliest history.
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