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J/AJ/130/2439       Redshift estimates in the SDSS DR2       (Suchkov+, 2005)

A census of object types and redshift estimates in the SDSS photometric catalog from a trained decision tree classifier. Suchkov A.A., Hanisch R.J., Margon B. <Astron. J., 130, 2439-2452 (2005)> =2005AJ....130.2439S
ADC_Keywords: Galaxy catalogs ; Photometry, SDSS ; Redshifts Keywords: astronomical data bases: miscellaneous - galaxies: active - galaxies: distances and redshifts - quasars: general Abstract: We have applied ClassX, an oblique decision tree classifier optimized for astronomical analysis, to the homogeneous multicolor imaging database of the Sloan Digital Sky Survey (SDSS), training the software on subsets of SDSS objects whose nature is precisely known via spectroscopy. We find that the software, using photometric data only, correctly classifies a very large fraction of the objects with existing SDSS spectra, both stellar and extragalactic. ClassX also accurately predicts the redshifts of both normal and active galaxies in SDSS. To illustrate ClassX applications in SDSS research, we (1) derive the object content of the SDSS Data Release 2 photometric catalog and (2) provide a sample catalog of resolved SDSS objects that contains a large number of candidate active galactic nucleus (AGN) galaxies (27,000), along with 63,000 candidate normal galaxies at magnitudes substantially fainter than the typical magnitudes of SDSS spectroscopic objects. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table5.dat 72 91847 Catalog of 91847 Galaxies and Resolved AGN from SDSS DR2 Photometric Catalog classified with ClassX
See also: II/259 : The SDSS Photometric Catalog, Release 3 (Abazajian+ 2005) : SDSS DR2 Home Page Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Seq Running number (1) 7- 15 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 17- 25 F9.5 deg DEdeg Declination in decimal degrees (J2000) 27- 31 F5.2 mag umag SDSS dereddened u band magnitude 33- 37 F5.2 mag gmag SDSS dereddened g band magnitude 39- 43 F5.2 mag rmag SDSS dereddened r band magnitude 45- 49 F5.2 mag imag SDSS dereddened i band magnitude 51- 55 F5.2 mag zmag SDSS dereddened z band magnitude 57- 60 F4.2 --- zlow Lower redshift limit 62- 65 F4.2 --- zup Upper redshift limit 67- 72 A6 --- Type Object type assigned by the classifier
Note (1): The catalog is the result of classification of a sample of 100,000 SDSS DR2 resolved photometric objects, of which 91,847 objects were classified as galaxies and AGN. The sample is constrained to the "faint" magnitude range (see text for details).
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Aug-2006
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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