Optical Identification of IRAS Faint Source Survey Sources with the ROE Southern Sky Optical Catalog

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Session 3 -- Galaxy Surveys
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[3.03] Optical Identification of IRAS Faint Source Survey Sources with the ROE Southern Sky Optical Catalog

T.P.Conrow, Carol J.Lonsdale, T.J.Chester, T.L.Evans, D.Egret, M.M.Moshir, L.D.Fullmer, B.F.Madore (IPAC), D.Yentis (NRL), R.D.Wolstencroft, H.M.MacGillivray (ROE)

We have performed an automated identification of all IRAS Faint Source Survey sources with ${\delta} < 3{\deg}$, $|b^{II}| \ga 10{\deg}$, with the ROE Southern Sky Optical Catalog, which lists positions and magnitudes for stars and galaxies to B$<$23, and for the whole sky with the Guide Star Catalog. We use a new identification probability technique based on likelihood ratios and random field matching. The identification results will be available for use by remote access to IPAC.

Optical identification to the GSC shows that for $|b| > 30{\deg}$, over 98\% of IRAS stars have a unique match with a reliability of 1.00. Fewer than 2\% have no reliable match at all, and fewer than 1\% have multiple matches with reliabilities $>$ 0. At lower galactic latitudes, the optical counterparts become too faint to be included in the GSC, and thus the number of sources with no reliable matches increases. For $|b| < 5{\deg}$, 56\% of the IRAS stars have no reliable matches. Sources with multiple matches with reliabilities $> 0$ never account for more than 5\% of the sample. Optical identification to the ROE Catalog results picks up more unique matches to IRAS stars at lower galactic latitudes.

The identification results for IRAS galaxies using the ROE Catalog show a smaller percentage of unique matches with high reliability, due to larger positional uncertainties, multiple galaxy systems, confusion with galaxy fragments and confusion with stars at low galactic latitudes: at $|b|>25{\deg}$ and SNR$>$10, $>$90\% of IRAS galaxies match a unique galaxy with reliability $>$80\%, and $>$7.5\% match $>$1 galaxy with reliability $>$80\%. For $15{\deg}<|b|<25{\deg}$, these numbers fall to 77\% for unique matches and 2\% for matches with $>$1 galaxy. Reliable galaxy matches can be found to the limit of the catalog in $b^{II}$.

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