Galaxy Evolution Explorer
When and where are stars born? GALEX
is a new ultra-violet telescope satellite that is to answer our questions
about the star formation history of the universe. As part of the GALEX
science team, I work on the UV galaxy luminosity function and evolution
of the mean luminosity density using photometric redshifts. I am also
interested in characterizing the clustering behavior of these galaxies
as well as their spectral energy distributions and physical properties.
Links
Sloan Digital Sky Survey
The Cosmic Genome project, SDSS is
one of the most ambitious surveys in astronomy. Its goal is to image
close to 10,000 square degrees of the northern sky and map the distribution
of close to 100,000,000 galaxies. My recent work on the angular correlation
function of galaxies with different spectral types shows that distribution
is bimodal similarly to their red and blue colors. Studying the large-scale
structure of the galaxies, the luminous matter, allows us to explore
the nature and dynamics of the universe.
Links
Virtual Observatory
The VO is an international initiative
to federate astronomical resources using interoperable services. I was
part of the small team at JHU that built the first prototype for catalog
archives. SkyQuery won 2nd prize
on the 2002 XML Web Services programming contest and currently provides
seamless access to over a dozen astronomical datasets. We have implemented
various other VO services including
the spectrum service that
currently publishes over 500,000 spectra from SDSS, 2dF and other surveys.
Our filter profile service
provides access to transmission curves of passbands of most photometric
systems and instruments.
Links
Hubble Space Telescope
This gem of the astronomy arsenal has been providing superb astronomical
images for over two decades. The Hubble
Deep Field (HDF) observations were the testbed for many new techniques
including photometric redshifts. In my PhD thesis, I derived photometric
redshifts for the HDF-N/NICMOS
catalog, in which the farthest
known supernova was found. The discovery of this distant Type Ia
supernova provides strong evidence that we live in an accelerating universe
that consists of mostly some dark
energy. As of today (April 2004), SN 1997ff supernova still holds
the record distance and the most convincing measurement for its redshift
was our
photometric redshift for the host galaxy, zphot = 1.7.
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