AAS 201st Meeting, January, 2003
Session 85. X-Rays
Poster, Wednesday, January 8, 2003, 9:20am-6:30pm, Exhibit Hall AB

[Previous] | [Session 85] | [Next]

[85.05] Preliminary Census of ROSAT Bright Sources: Results from ClassX

R.L. White, A.A. Suchkov, R.J. Hanisch, M. Postman, M.E. Donahue (STScI), T.A. McGlynn, E.L. Winter, M.F Corcoran, S.A. Drake, W.D. Pence, N. White, L. Angelini (NASA/GSFC), F. Genova, F. Ochsenbein, P. Fernique, S. Derriere (CDS), W. Voges (MPIE)

ClassX is being developed as a system for automated classification of X-ray sources within the Virtual Observatory environment. Its core is a network of classifiers ``trained'' using diverse data sets for X-ray sources of known object type and their optical, infrared, radio, etc. counterparts. The network is integrated in the ClassX pipeline with a search engine that queries remote multi-wavelength data repositories, using systems such as CDS VizieR service, to get data (in the VOTable format) for the sources to be classified. In this paper we present a preliminary census from ClassX for earlier unclassified X-ray sources observed with the ROSAT PSPC and compare it with the frequency of object types in samples of previously classified sources. The early results include findings that our sources are dominated by QSOs followed by clusters of galaxies. Previously classified sources are by contrast dominated by stars. Since these star-dominated samples were used to train our classifiers, the predominance of extragalactic sources is all the more striking. We find it encouraging that the ClassX census appear to be quite consistent with expectations based on the analysis of flux differences of previously classified and unclassified sources, while the variations between census versions from different classifiers are rather transparently related to the classifier differences.

[Previous] | [Session 85] | [Next]

Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.