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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 660700.0, MPI für Astronomie / Publikationen_mpia
The Photometric Classification Server for Pan-STARRS1
Authors:Saglia, R. P.; Tonry, J. L.; Bender, R.; Greisel, N.; Seitz, S.; Senger, R.; Snigula, J.; Phleps, S.; Wilman, D.; Bailer-Jones, C. A. L.; Klement, R. J.; Rix, H. -. W.; Smith, K.; Green, P. J.; Burgett, W. S.; Chambers, K. C.; Heasley, J. N.; Kaiser, N.; Magnier, E. A.; Morgan, J. S.; Price, P. A.; Stubbs, C. W.; Wainscoat, R. J.
Date of Publication (YYYY-MM-DD):2012
Journal Abbrev.:The Astrophysical Journal
Issue / Number:2
Start Page:id. 128
Audience:Not Specified
Abstract / Description:The Pan-STARRS1 survey is obtaining multi-epoch imaging in five bands (g P1 r P1 i P1 z P1 y P1) over the entire sky north of declination -30 deg. We describe here the implementation of the Photometric Classification Server (PCS) for Pan-STARRS1. PCS will allow the automatic classification of objects into star/galaxy/quasar classes based on colors and the measurement of photometric redshifts for extragalactic objects, and will constrain stellar parameters for stellar objects, working at the catalog level. We present tests of the system based on high signal-to-noise photometry derived from the Medium-Deep Fields of Pan-STARRS1, using available spectroscopic surveys as training and/or verification sets. We show that the Pan-STARRS1 photometry delivers classifications and photometric redshifts as good as the Sloan Digital Sky Survey (SDSS) photometry to the same magnitude limits. In particular, our preliminary results, based on this relatively limited data set down to the SDSS spectroscopic limits, and therefore potentially improvable, show that stars are correctly classified as such in 85% of cases, galaxies in 97%, and QSOs in 84%. False positives are less than 1% for galaxies, ≈19% for stars, and ≈28% for QSOs. Moreover, photometric redshifts for 1000 luminous red galaxies up to redshift 0.5 are determined to 2.4% precision (defined as 1.48 × Median|z phot - z spec|/(1 + z)) with just 0.4% catastrophic outliers and small (-0.5%) residual bias. For bluer galaxies up to the same redshift, the residual bias (on average -0.5%) trend, percentage of catastrophic failures (1.2%), and precision (4.2%) are higher, but still interestingly small for many science applications. Good photometric redshifts (to 5%) can be obtained for at most 60% of the QSOs of the sample. PCS will create a value-added catalog with classifications and photometric redshifts for eventually many millions of sources.
Free Keywords:galaxies: active; galaxies: distances and redshifts; stars: general; surveys
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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