AAS 207th Meeting, 8-12 January 2006
Session 63 From Here to Eternity: The Spitzer Legacy Programs
Poster, Tuesday, 9:20am-6:30pm, January 10, 2006, Exhibit Hall

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[63.44] Stellar Objects with Infrared Excess in the \textit{Spitzer Space Telescope} Wide-Area Infrared Extragalactic Survey (SWIRE)

F. Y. Morales, M. W. Werner (JPL, Caltech), D. Padgett, S. Fajardo-Acosta, D. Stevens Stern, R-R. Chary, S. Dawson, M. Dickinson, J.R. Stauffer, B. Smith, S. Walton, A.C. Cadavid (SSC/IPAC, CalTech), SWIRE Team, Ana Christina Cadavid Collaboration

We have identified two new debris disk candidates in the \textit{Spitzer Space Telescope} Legacy Project Wide-Area InfraRed Extragalactic Survey (SWIRE). We searched two of the six SWIRE photometric survey fields, and present 3.6-160 \mum photometry obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer (MIPS) instruments. We followed up the candidates with spectro-photometry from 4-36 \mum using the Infrared Spectrometer (IRS) low resolution modules. The candidates spectral energy distributions (SEDs) were constructed from Keck's LRIS optical spectroscopy, \textit{2MASS} J, H, Ks, \textit{Spitzer's} IRAC 3.6, 4.5, 5.8, 8.0 \mum bands, and MIPS 24 m photometry (70 and 160 \mum when detected). The two candidates, Lockman_tile32_1228 and EN1_tile22_11767, were selected by their 24 \mum emission above photospheric expected levels, an indicator of the Vega phenomenon, or the presence of circumstellar dust at ~120 K. Object Lockman_tile32_1228 has 70 and 160 \mum surplus in flux, suggesting the presence of cold dust represented by blackbody curves of ~65 and ~23 Kelvin. The infrared spectra reveal both sources to have infrared excess at wavelengths shorter than 24 \mum as well. The shape of Lockman_tile32_1228's SED exhibits interesting features from 8 to 20 \mum, possibly due to the composition of the emitting material. To confirm these sources are stellar objects, 0.32-0.95 \mum optical spectra was obtained via W.M. Keck Observatory's LRIS dual spectrometer. LRIS blue and red arm spectroscopy confirms the candidates are K-type main sequence stars about 195 and 160 pc away from the Sun. At high-galactic latitudes, where interstellar material is scarce, the SEDs of these sources illustrate there can exist a diversity of debris disk evolutionary states in foreground stars of the Galaxy.

This work is based on observations made with \textit{Spitzer Space Telescope}, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407.

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