Signatures of past events in the Milky Way can be found in the
form of structures in the position, velocity, and chemical
abundance space. To study this, large amounts of multi-dimensional
data already exists and numerous upcoming missions will create
even larger and complex datasets. To efficiently and accurately
analyze such datasets we develop a group finding algorithm which
can work in a space of arbitrary number and type of dimensions.
We develop a novel scheme which uses the idea of Shannon entropy
to calculate a locally adaptive distance metric for each data point
so as to extract maximum information from the data. We first apply
this to the 2MASS data set (data with 2 angular positions and radial
distance) and successfully identify some of the known structures
in the form of tidal streams and dwarf galaxies and also predict
some new structures. In order to understand the accretion history
of the Milky Way we compare these results with synthetic surveys
created out of simulated stellar halos (constructed within the LCDM
cosmology). With an eye on future upcoming missions like GAIA and
WFMOS; which will also have additional information in the form of
proper motion, radial velocity and chemical abundances, we create
similar synthetic surveys from our simulated stellar halos and analyze
them. We show how adding the velocity and abundance information
greatly improves the identification of structures. We also study the
effect of observational errors on the identification of structures.
View poster as pdf.