J/MNRAS/450/3893 SDSS DR10 catalogue of candidate quasars (Brescia+, 2015) ================================================================================ Automated physical classification in the SDSS DR10. A catalogue of candidate quasars. Brescia M., Cavuoti S., Longo G. =2015MNRAS.450.3893B ================================================================================ ADC_Keywords: Active gal. nuclei ; QSOs ; Photometry, SDSS ; Redshifts Keywords: methods: data analysis - techniques: photometric - catalogues - galaxies: active - quasars: general Abstract: We discuss whether modern machine learning methods can be used to characterize the physical nature of the large number of objects sampled by the modern multi-band digital surveys. In particular, we applied the MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) method to the optical data of the Sloan Digital Sky Survey - Data Release 10, investigating whether photometric data alone suffice to disentangle different classes of objects as they are defined in the SDSS spectroscopic classification. We discuss three groups of classification problems: (i) the simultaneous classification of galaxies, quasars and stars; (ii) the separation of stars from quasars; (iii) the separation of galaxies with normal spectral energy distribution from those with peculiar spectra, such as starburst or starforming galaxies and AGN. While confirming the difficulty of disentangling AGN from normal galaxies on a photometric basis only, MLPQNA proved to be quite effective in the three-class separation. In disentangling quasars from stars and galaxies, our method achieved an overall efficiency of 91.31% and a QSO class purity of ~95%. The resulting catalogue of candidate quasars/AGNs consists of ~3.6 million objects, of which about half a million are also flagged as robust candidates. Description: The file DAME_QSO_catalogue.dat contains a photometric catalog of 3602210 candidate quasars/AGNs objects. The objects are referred to the SDSS DR10 archive. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file dame_qso.dat 228 3602210 Candidate QSO/AGN Objects from SDSS-DR10 -------------------------------------------------------------------------------- See also: VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014) http://www.sdss.org : SDSS Home Page Byte-by-byte Description of file: dame_qso.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 I19 --- objID Unique SDSS identifier 21- 43 E23.18 deg RAdeg Right Ascension (J2000) 45- 67 E23.19 deg DEdeg Declination (J2000) 69- 77 F9.6 mag umag SDSS PSF magnitude in band u 79- 87 F9.6 mag gmag SDSS PSF magnitude in band g 89- 97 F9.6 mag rmag SDSS PSF magnitude in band r 99-107 F9.6 mag imag SDSS PSF magnitude in band i 109-117 F9.6 mag zmag SDSS PSF magnitude in band z 119-127 F9.6 mag u'mag SDSS better of DeV/Exp mag fit in band u 129-138 F10.7 mag g'mag SDSS better of DeV/Exp mag fit in band g 140-149 F10.7 mag r'mag SDSS better of DeV/Exp mag fit in band r 151-160 F10.7 mag i'mag SDSS better of DeV/Exp mag fit in band i 162-171 F10.7 mag z'mag SDSS better of DeV/Exp mag fit in band z 173-191 I19 --- specID ? Unique SDSS spectroscopic identifier 193-213 A21 --- subclass ? SDSS spectroscopic subclass (1) 215-226 E12.8 --- z [0/7.1]? SDSS spectroscopic redshift 228 I1 --- Qf [0/1] Quality Flag: 0=basic, 1=high -------------------------------------------------------------------------------- Note (1): the subclasses (with the number of sources) are: 294: AGN 312: AGN_BROADLINE 157336: BROADLINE 130: STARBURST 5512: STARBURST_BROADLINE 38: STARFORMING 198: STARFORMING_BROADLINE -------------------------------------------------------------------------------- Acknowledgements: Massimo Brescia, bresciamax(at)gmail.com ================================================================================ (End) Massimo Brescia [INAF-OACN, Italy], Patricia Vannier [CDS] 15-Apr-2015