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J/A+A/568/A126      SDSS-DR9 photometric redshifts           (Brescia+, 2014)

A catalogue of photometric redshifts for the SDSS-DR9 galaxies. Brescia M., Cavuoti S., Longo G., De Stefano V. <Astron. Astrophys. 568, A126 (2014)> =2014A&A...568A.126B
ADC_Keywords: Galaxy catalogs ; Galaxies, photometry ; Photometry, SDSS ; Redshifts Keywords: techniques: photometric - galaxies: distances and redshifts - galaxies: photometry - methods: data analysis - catalogs Abstract: Accurate photometric redshifts for large samples of galaxies are among the main products of modern multiband digital surveys. Over the last decade, the Sloan Digital Sky Survey (SDSS) has become a sort of benchmark against which to test the various methods. We present an application of a new method to the estimation of photometric redshifts for the galaxies in the SDSS Data Release 9 (SDSS-DR9). Photometric redshifts for more than 143 million galaxies were produced. The MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) model provided within the framework of the DAMEWARE (DAta Mining and Exploration Web Application REsource) is an interpolative method derived from machine learning models. The obtained redshifts have an overall uncertainty of sigma=0.023 with a very small average bias of about 3x10^-5, and a fraction of catastrophic outliers of about 5%. This result is slightly better than what was already available in the literature, particularly in terms of the smaller fraction of catastrophic outliers. Description: We present an application of a machine learning method to the estimation of photometric redshifts for the galaxies in the SDSS Data Release 9 (SDSS-DR9). Photometric redshifts for more than 143 million galaxies were produced. The MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) model provided within the framework of the DAMEWARE (DAta Mining and Exploration Web Application REsource) is an interpolative method derived from machine learning models. The obtained redshifts have an overall uncertainty of σ=0.023 with a very small average bias of about 3x10-5 and a fraction of catastrophic outliers of about 5%. After removal of the catastrophic outliers, the uncertainty is about σ=0.017. The catalogue files report in their name the range of DEC degrees related to the included objects. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file r00_01.dat 186 3174048 Photo-z for objects with DEC in [+00, +01[ deg r01_02.dat 186 2622557 Photo-z for objects with DEC in [+01, +02[ deg r02_03.dat 186 2425949 Photo-z for objects with DEC in [+02, +03[ deg r03_04.dat 186 2452418 Photo-z for objects with DEC in [+03, +04[ deg r04_05.dat 186 2581739 Photo-z for objects with DEC in [+04, +05[ deg r05_06.dat 186 2584264 Photo-z for objects with DEC in [+05, +06[ deg r06_07.dat 186 2573026 Photo-z for objects with DEC in [+06, +07[ deg r07_08.dat 186 2527441 Photo-z for objects with DEC in [+07, +08[ deg r08_09.dat 186 2477638 Photo-z for objects with DEC in [+08, +09[ deg r09_10.dat 186 2446000 Photo-z for objects with DEC in [+09, +10[ deg r10_11.dat 186 2421873 Photo-z for objects with DEC in [+10, +11[ deg r11_12.dat 186 2345616 Photo-z for objects with DEC in [+11, +12[ deg r12_13.dat 186 2368326 Photo-z for objects with DEC in [+12, +13[ deg r13_14.dat 186 2399749 Photo-z for objects with DEC in [+13, +14[ deg r14_15.dat 186 2481196 Photo-z for objects with DEC in [+14, +15[ deg r15_16.dat 186 2453102 Photo-z for objects with DEC in [+15, +16[ deg r16_17.dat 186 2424682 Photo-z for objects with DEC in [+16, +17[ deg r17_18.dat 186 2443693 Photo-z for objects with DEC in [+17, +18[ deg r18_19.dat 186 2393301 Photo-z for objects with DEC in [+18, +19[ deg r19_20.dat 186 2344795 Photo-z for objects with DEC in [+19, +20[ deg r20_21.dat 186 2302416 Photo-z for objects with DEC in [+20, +21[ deg r21_22.dat 186 2306628 Photo-z for objects with DEC in [+21, +22[ deg r22_23.dat 186 2324688 Photo-z for objects with DEC in [+22, +23[ deg r23_24.dat 186 2316396 Photo-z for objects with DEC in [+23, +24[ deg r24_25.dat 186 2346731 Photo-z for objects with DEC in [+24, +25[ deg r25_26.dat 186 2345722 Photo-z for objects with DEC in [+25, +26[ deg r26_27.dat 186 2309884 Photo-z for objects with DEC in [+26, +27[ deg r27_28.dat 186 2278879 Photo-z for objects with DEC in [+27, +28[ deg r28_29.dat 186 2234187 Photo-z for objects with DEC in [+28, +29[ deg r29_30.dat 186 2219295 Photo-z for objects with DEC in [+29, +30[ deg r30_31.dat 186 2162802 Photo-z for objects with DEC in [+30, +31[ deg r31_32.dat 186 2080848 Photo-z for objects with DEC in [+31, +32[ deg r32_33.dat 186 1982223 Photo-z for objects with DEC in [+32, +33[ deg r33_34.dat 186 1936611 Photo-z for objects with DEC in [+33, +34[ deg r34_35.dat 186 1870717 Photo-z for objects with DEC in [+34, +35[ deg r35_36.dat 186 1780638 Photo-z for objects with DEC in [+35, +36[ deg r36_38.dat 186 3372102 Photo-z for objects with DEC in [+36, +38[ deg r38_40.dat 186 3406218 Photo-z for objects with DEC in [+38, +40[ deg r40_42.dat 186 3259750 Photo-z for objects with DEC in [+40, +42[ deg r42_44.dat 186 3185334 Photo-z for objects with DEC in [+42, +44[ deg r44_46.dat 186 2965157 Photo-z for objects with DEC in [+44, +46[ deg r46_48.dat 186 2589271 Photo-z for objects with DEC in [+46, +48[ deg r48_50.dat 186 2313002 Photo-z for objects with DEC in [+48, +50[ deg r50_53.dat 186 3180836 Photo-z for objects with DEC in [+50, +53[ deg r53_56.dat 186 2957915 Photo-z for objects with DEC in [+53, +56[ deg r56_60.dat 186 3426159 Photo-z for objects with DEC in [+56, +60[ deg r60_65.dat 186 3815459 Photo-z for objects with DEC in [+60, +65[ deg r65_70.dat 186 1677346 Photo-z for objects with DEC in [+65, +70[ deg r70_85.dat 186 1337222 Photo-z for objects with DEC in [+70, +85[ deg r-01_00.dat 186 3182508 Photo-z for objects with DEC in [-01, +00[ deg r-02_-01.dat 186 2471559 Photo-z for objects with DEC in [-02, -01[ deg r-04_-02.dat 186 3808610 Photo-z for objects with DEC in [-04, -02[ deg r-06_-04.dat 186 2637920 Photo-z for objects with DEC in [-06, -04[ deg r-08_-06.dat 186 2661702 Photo-z for objects with DEC in [-08, -06[ deg r-10_-08.dat 186 2006992 Photo-z for objects with DEC in [-10, -08[ deg r-15_-10.dat 186 2175039 Photo-z for objects with DEC in [-15, -10[ deg r-20_-15.dat 186 1693609 Photo-z for objects with DEC in [-20, -15[ deg r-30_-20.dat 186 702996 Photo-z for objects with DEC in [-30, -20[ deg rspecial.dat 186 18006 *Photo-z for special SDSS objects fits/* 0 59 Tables as fits files
Note on rspecial.dat: photo-z for SDSS special objects with a mismatch between photometric and spectroscopic class assignment.
See also: http://www.sdss.org : SDSS Home Page Byte-by-byte Description of file: r*.dat
Bytes Format Units Label Explanations
1- 19 I19 --- objID Unique SDSS identifier 21- 29 F9.5 deg RAdeg Right Ascension (J2000) 31- 39 F9.5 deg DEdeg Declination (J2000) 41- 46 F6.3 mag umag [0/40] u-band PSF magnitude 48- 53 F6.3 mag gmag [0/40] g-band PSF magnitude 55- 60 F6.3 mag rmag [0/40] r-band PSF magnitude 62- 67 F6.3 mag imag [0/40] i-band PSF magnitude 69- 74 F6.3 mag zmag [0/40] z-band PSF magnitude 76- 81 F6.3 mag e_umag ?=99.999 u-band PSF magnitude error 83- 88 F6.3 mag e_gmag ?=99.999 g-band PSF magnitude error 90- 95 F6.3 mag e_rmag ?=99.999 r-band PSF magnitude error 97-102 F6.3 mag e_imag ?=99.999 i-band PSF magnitude error 104-109 F6.3 mag e_zmag ?=99.999 z-band PSF magnitude error 111-116 F6.3 mag extu ?=99.999 Extinction in u-band 118-123 F6.3 mag extg ?=99.999 Extinction in g-band 125-130 F6.3 mag extr ?=99.999 Extinction in r-band 132-137 F6.3 mag exti ?=99.999 Extinction in i-band 139-144 F6.3 mag extz ?=99.999 Extinction in z-band 146-152 F7.3 mag u-g u-g color index from PSF SDSS magnitudes 154-160 F7.3 mag g-r g-r color index from PSF SDSS magnitudes 162-168 F7.3 mag r-i r-i color index from PSF SDSS magnitudes 170-176 F7.3 mag i-z i-z color index from PSF SDSS magnitudes 178-184 F7.5 --- zphot Estimated photometric redshift 186 I1 --- q_zphot [0/3] Quality Flag of the zphot: 0=none, 1=high, 2=medium, 3=low
Acknowledgements: Massimo Brescia, bresciamax(at)gmail.com
(End) Massimo Brescia [INAF-OACN, Italy], Patricia Vannier [CDS] 15-Jul-2014
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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