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Session 14 - Various Stellar Surveys.
Display session, Wednesday, January 07
Exhibit Hall,

[14.03] The FIRST Unbiased Survey for Radio Sources

D. J. Helfand, S. Schnee (Columbia U.), R. H. Becker (UC Davis and IGPP), R. L. White (STScI), R. G. McMahon (Cambridge)

Of the 100,000 brightest sources in the radio sky, fewer than 20 are stars. Nonetheless, as a consequence of targeted searches of optically selected samples, nearly 1000 sources of stellar radio emission have been identified since the advent 25 years ago of sensitive radio interferometers operating at centimeter wavelengths. Stellar objects with high radio luminosities include dMe flare stars, rapidly rotating young stars, some pre- and post-main sequence stars, and various classes of close binary systems. To date, however, no radio survey has had the sensitivity and astrometric accuracy to produce a radio-selected stellar sample. The VLA FIRST radio survey, now complete over 5000 square degrees, provides the first such sample to a sub-millijansky threshold. We have compared the FIRST catalog with the Hipparcos and Tycho catalogs of bright stars, as well as with other stellar catalogs with the requisite proper motion information. Several dozen radio stars are detected, more than tripling the number of known radio stars in our survey region. Many of these sources are shown to be highly variable through comparison of observations in the overlap regions of the FIRST pointing grid. We find additional stellar radio emitters at fainter flux densities by comparing the Hipparcos and Tycho positions directly to the FIRST images. We quantify the increase in stellar identifications that the GSC II catalog will provide, and discuss the implications for stellar radio luminosity functions that this FIRST unbiased survey for radio stars provides.

The FIRST project is supported by grants from the National Geographic Society, the National Science Foundation, NATO, IGPP, Columbia University, and Sun Microsystems.

Program listing for Wednesday