Galaxy Decomposition Service

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Galaxy Decomposition Service

• Yogesh Wadadekar (STScI)
• Milan Bogosavljevic (Caltech)
• Ashish Mahabal (Caltech)

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Science driversHow do Hubble types evolve with
redshift? At what redshift does the Hubble
sequence form? Does galaxy formation occur
heirarchically or through primodial collapse?
How does the morphology in clusters change as a
function of cluster mass and distance from
cluster center?TOOL Galaxy photometric
decomposition code (FITGAL) performs a chi2
minimization between a user provided galaxy image
and a multicomponent (bulge,disk,point etc.)
model.
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• Why another web service?
• Obtaining the global minimum of a complicated
  multidimensional chi2 surface is something of a
  black art
• Many users can test the code on different data
  in minutes
• (no compiling! ) )
• Building a new Web service
• (small step for mankind, big for ...)
• We converted a stand alone program into a Web
  tool.
• Simplest approach
• - Input HTML form
• - CGI program to transfer user files to STScI
• and launch child process
• - User can visually monitor progress in
  browser,
• or run from command line.

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The Web service interface
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Submitting job to STScI...
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Monitoring the iterations....
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All done
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• A little bit about the code
• (Wadadekar et al, AJ, 1999)

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• Bigger goals for the future
• Integrating the web service to query other
  imaging services for galaxies to your liking you
  dont need to have any data locally.
• combine this service with GRID resources so that
  users can process large samples. We will
  ourselves attempt to run this code on millions of
  Sloan survey galaxies using the Teragrid.
• Our extracted parameters can be added as extra
  columns to the Sloan catalog and made accessible
  to the community through Openskyquery.