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J/AJ/140/390    Karhunen-Loeve transform of SDSS QSOs        (Boroson+, 2010)

Exploring the spectral space of low redshift QSOs. Boroson T.A., Lauer T.R. <Astron. J., 140, 390-402 (2010)> =2010AJ....140..390B
ADC_Keywords: QSOs ; Spectroscopy ; Models Keywords: methods: data analysis - methods: numerical - methods: statistical - quasars: emission lines Abstract: The Karhunen-Loeve (KL) transform can compactly represent the information contained in large, complex datasets, cleanly eliminating noise from the data and identifying elements of the dataset with extreme or inconsistent characteristics. We develop techniques to apply the KL transform to the 4000-5700Å region of 9800 QSO spectra with z<0.619 from the SDSS archive. Up to 200 eigenspectra are needed to fully reconstruct the spectra in this sample to the limit of their signal-to-noise (S/N). We propose a simple formula for selecting the optimum number of eigenspectra to use to reconstruct any given spectrum, based on the S/N of the spectrum, but validated by formal cross-validation tests. Description: The QSO sample is a low redshift subset from the fourth version of the SDSS Quasar Catalog (Schneider et al. 2007, Cat. VII/252, SDSSQ4). This catalog is based on the fifth SDSS data release (DR5), and is limited to objects that have absolute I-band magnitude brighter than -22, and have at least one emission line with an FWHM larger than 1000km/s. The QSOs having redshifts below 0.619 (9800 objects) were drawn from this catalog. This upper redshift cutoff allows complete coverage of the 4000-5700Å rest-frame region. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 2007 1540 Eigenspectra table2.dat 1318 9800 Reconstruction weights for the QSO Sample table3.dat 20 114 Outliers
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 7 F7.2 0.1nm lambda Wavelength of center pixel (Å) 8-2007 200F10.6 --- E Value of eigenspectrum (1 to 200 pixel)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 18 A18 --- SDSS SDSS identification (HHMMSS.ss+DDMMSS.s) 20- 25 F6.4 --- z Redshift 27- 34 F8.2 --- Norm Normalization to units of 10-17erg/s/cm2/Å 36- 38 I3 --- Num Number of eigenspectra to be used 40- 46 F7.4 --- Chi2 Reduced χ-squared cross-validation value 48- 54 F7.4 --- a1 Weight for eigenspectrum 1 56- 62 F7.4 --- a2 Weight for eigenspectrum 2 64- 70 F7.4 --- a3 Weight for eigenspectrum 3 72- 78 F7.4 --- a4 Weight for eigenspectrum 4 80- 86 F7.4 --- a5 Weight for eigenspectrum 5 88- 94 F7.4 --- a6 Weight for eigenspectrum 6 96-102 F7.4 --- a7 Weight for eigenspectrum 7 104-110 F7.4 --- a8 Weight for eigenspectrum 8 112-118 F7.4 --- a9 Weight for eigenspectrum 9 120-126 F7.4 --- a10 Weight for eigenspectrum 10 128-134 F7.4 --- a11 Weight for eigenspectrum 11 136-142 F7.4 --- a12 Weight for eigenspectrum 12 144-150 F7.4 --- a13 Weight for eigenspectrum 13 152-158 F7.4 --- a14 Weight for eigenspectrum 14 160-166 F7.4 --- a15 Weight for eigenspectrum 15 168-174 F7.4 --- a16 Weight for eigenspectrum 16 176-182 F7.4 --- a17 Weight for eigenspectrum 17 184-190 F7.4 --- a18 Weight for eigenspectrum 18 192-198 F7.4 --- a19 Weight for eigenspectrum 19 200-206 F7.4 --- a20 Weight for eigenspectrum 20 208-214 F7.4 --- a21 Weight for eigenspectrum 21 216-222 F7.4 --- a22 Weight for eigenspectrum 22 224-230 F7.4 --- a23 Weight for eigenspectrum 23 232-238 F7.4 --- a24 Weight for eigenspectrum 24 240-246 F7.4 --- a25 Weight for eigenspectrum 25 248-254 F7.4 --- a26 Weight for eigenspectrum 26 256-262 F7.4 --- a27 Weight for eigenspectrum 27 264-270 F7.4 --- a28 Weight for eigenspectrum 28 272-278 F7.4 --- a29 Weight for eigenspectrum 29 280-286 F7.4 --- a30 Weight for eigenspectrum 30 288-294 F7.4 --- a31 Weight for eigenspectrum 31 296-302 F7.4 --- a32 Weight for eigenspectrum 32 304-310 F7.4 --- a33 ? Weight for eigenspectrum 33 312-318 F7.4 --- a34 ? Weight for eigenspectrum 34 320-326 F7.4 --- a35 ? Weight for eigenspectrum 35 328-334 F7.4 --- a36 ? Weight for eigenspectrum 36 336-342 F7.4 --- a37 ? Weight for eigenspectrum 37 344-350 F7.4 --- a38 ? Weight for eigenspectrum 38 352-358 F7.4 --- a39 ? Weight for eigenspectrum 39 360-366 F7.4 --- a40 ? Weight for eigenspectrum 40 368-374 F7.4 --- a41 ? Weight for eigenspectrum 41 376-382 F7.4 --- a42 ? Weight for eigenspectrum 42 384-390 F7.4 --- a43 ? Weight for eigenspectrum 43 392-398 F7.4 --- a44 ? Weight for eigenspectrum 44 400-406 F7.4 --- a45 ? Weight for eigenspectrum 45 408-414 F7.4 --- a46 ? Weight for eigenspectrum 46 416-422 F7.4 --- a47 ? Weight for eigenspectrum 47 424-430 F7.4 --- a48 ? Weight for eigenspectrum 48 432-438 F7.4 --- a49 ? Weight for eigenspectrum 49 440-446 F7.4 --- a50 ? Weight for eigenspectrum 50 448-454 F7.4 --- a51 ? Weight for eigenspectrum 51 456-462 F7.4 --- a52 ? Weight for eigenspectrum 52 464-470 F7.4 --- a53 ? Weight for eigenspectrum 53 472-478 F7.4 --- a54 ? Weight for eigenspectrum 54 480-486 F7.4 --- a55 ? Weight for eigenspectrum 55 488-494 F7.4 --- a56 ? Weight for eigenspectrum 56 496-502 F7.4 --- a57 ? Weight for eigenspectrum 57 504-510 F7.4 --- a58 ? Weight for eigenspectrum 58 512-518 F7.4 --- a59 ? Weight for eigenspectrum 59 520-526 F7.4 --- a60 ? Weight for eigenspectrum 60 528-534 F7.4 --- a61 ? Weight for eigenspectrum 61 536-542 F7.4 --- a62 ? Weight for eigenspectrum 62 544-550 F7.4 --- a63 ? Weight for eigenspectrum 63 552-558 F7.4 --- a64 ? Weight for eigenspectrum 64 560-566 F7.4 --- a65 ? Weight for eigenspectrum 65 568-574 F7.4 --- a66 ? Weight for eigenspectrum 66 576-582 F7.4 --- a67 ? Weight for eigenspectrum 67 584-590 F7.4 --- a68 ? Weight for eigenspectrum 68 592-598 F7.4 --- a69 ? Weight for eigenspectrum 69 600-606 F7.4 --- a70 ? Weight for eigenspectrum 70 608-614 F7.4 --- a71 ? Weight for eigenspectrum 71 616-622 F7.4 --- a72 ? Weight for eigenspectrum 72 624-630 F7.4 --- a73 ? Weight for eigenspectrum 73 632-638 F7.4 --- a74 ? Weight for eigenspectrum 74 640-646 F7.4 --- a75 ? Weight for eigenspectrum 75 648-654 F7.4 --- a76 ? Weight for eigenspectrum 76 656-662 F7.4 --- a77 ? Weight for eigenspectrum 77 664-670 F7.4 --- a78 ? Weight for eigenspectrum 78 672-678 F7.4 --- a79 ? Weight for eigenspectrum 79 680-686 F7.4 --- a80 ? Weight for eigenspectrum 80 688-694 F7.4 --- a81 ? Weight for eigenspectrum 81 696-702 F7.4 --- a82 ? Weight for eigenspectrum 82 704-710 F7.4 --- a83 ? Weight for eigenspectrum 83 712-718 F7.4 --- a84 ? Weight for eigenspectrum 84 720-726 F7.4 --- a85 ? Weight for eigenspectrum 85 728-734 F7.4 --- a86 ? Weight for eigenspectrum 86 736-742 F7.4 --- a87 ? Weight for eigenspectrum 87 744-750 F7.4 --- a88 ? Weight for eigenspectrum 88 752-758 F7.4 --- a89 ? Weight for eigenspectrum 89 760-766 F7.4 --- a90 ? Weight for eigenspectrum 90 768-774 F7.4 --- a91 ? Weight for eigenspectrum 91 776-782 F7.4 --- a92 ? Weight for eigenspectrum 92 784-790 F7.4 --- a93 ? Weight for eigenspectrum 93 792-798 F7.4 --- a94 ? Weight for eigenspectrum 94 800-806 F7.4 --- a95 ? Weight for eigenspectrum 95 808-814 F7.4 --- a96 ? Weight for eigenspectrum 96 816-822 F7.4 --- a97 ? Weight for eigenspectrum 97 824-830 F7.4 --- a98 ? Weight for eigenspectrum 98 832-838 F7.4 --- a99 ? Weight for eigenspectrum 99 840-846 F7.4 --- a100 ? Weight for eigenspectrum 100 848-854 F7.4 --- a101 ? Weight for eigenspectrum 101 856-862 F7.4 --- a102 ? Weight for eigenspectrum 102 864-870 F7.4 --- a103 ? Weight for eigenspectrum 103 872-878 F7.4 --- a104 ? Weight for eigenspectrum 104 880-886 F7.4 --- a105 ? Weight for eigenspectrum 105 888-894 F7.4 --- a106 ? Weight for eigenspectrum 106 896-902 F7.4 --- a107 ? Weight for eigenspectrum 107 904-910 F7.4 --- a108 ? Weight for eigenspectrum 108 912-918 F7.4 --- a109 ? Weight for eigenspectrum 109 920-926 F7.4 --- a110 ? Weight for eigenspectrum 110 928-934 F7.4 --- a111 ? Weight for eigenspectrum 111 936-942 F7.4 --- a112 ? Weight for eigenspectrum 112 944-950 F7.4 --- a113 ? Weight for eigenspectrum 113 952-958 F7.4 --- a114 ? Weight for eigenspectrum 114 960-966 F7.4 --- a115 ? Weight for eigenspectrum 115 968-974 F7.4 --- a116 ? Weight for eigenspectrum 116 976-982 F7.4 --- a117 ? Weight for eigenspectrum 117 984-990 F7.4 --- a118 ? Weight for eigenspectrum 118 992-998 F7.4 --- a119 ? Weight for eigenspectrum 119 1000-1006 F7.4 --- a120 ? Weight for eigenspectrum 120 1008-1014 F7.4 --- a121 ? Weight for eigenspectrum 121 1016-1022 F7.4 --- a122 ? Weight for eigenspectrum 122 1024-1030 F7.4 --- a123 ? Weight for eigenspectrum 123 1032-1038 F7.4 --- a124 ? Weight for eigenspectrum 124 1040-1046 F7.4 --- a125 ? Weight for eigenspectrum 125 1048-1054 F7.4 --- a126 ? Weight for eigenspectrum 126 1056-1062 F7.4 --- a127 ? Weight for eigenspectrum 127 1064-1070 F7.4 --- a128 ? Weight for eigenspectrum 128 1072-1078 F7.4 --- a129 ? Weight for eigenspectrum 129 1080-1086 F7.4 --- a130 ? Weight for eigenspectrum 130 1088-1094 F7.4 --- a131 ? Weight for eigenspectrum 131 1096-1102 F7.4 --- a132 ? Weight for eigenspectrum 132 1104-1110 F7.4 --- a133 ? Weight for eigenspectrum 133 1112-1118 F7.4 --- a134 ? Weight for eigenspectrum 134 1120-1126 F7.4 --- a135 ? Weight for eigenspectrum 135 1128-1134 F7.4 --- a136 ? Weight for eigenspectrum 136 1136-1142 F7.4 --- a137 ? Weight for eigenspectrum 137 1144-1150 F7.4 --- a138 ? Weight for eigenspectrum 138 1152-1158 F7.4 --- a139 ? Weight for eigenspectrum 139 1160-1166 F7.4 --- a140 ? Weight for eigenspectrum 140 1168-1174 F7.4 --- a141 ? Weight for eigenspectrum 141 1176-1182 F7.4 --- a142 ? Weight for eigenspectrum 142 1184-1190 F7.4 --- a143 ? Weight for eigenspectrum 143 1192-1198 F7.4 --- a144 ? Weight for eigenspectrum 144 1200-1206 F7.4 --- a145 ? Weight for eigenspectrum 145 1208-1214 F7.4 --- a146 ? Weight for eigenspectrum 146 1216-1222 F7.4 --- a147 ? Weight for eigenspectrum 147 1224-1230 F7.4 --- a148 ? Weight for eigenspectrum 148 1232-1238 F7.4 --- a149 ? Weight for eigenspectrum 149 1240-1246 F7.4 --- a150 ? Weight for eigenspectrum 150 1248-1254 F7.4 --- a151 ? Weight for eigenspectrum 151 1256-1262 F7.4 --- a152 ? Weight for eigenspectrum 152 1264-1270 F7.4 --- a153 ? Weight for eigenspectrum 153 1272-1278 F7.4 --- a154 ? Weight for eigenspectrum 154 1280-1286 F7.4 --- a155 ? Weight for eigenspectrum 155 1288-1294 F7.4 --- a156 ? Weight for eigenspectrum 156 1296-1302 F7.4 --- a157 ? Weight for eigenspectrum 157 1304-1310 F7.4 --- a158 ? Weight for eigenspectrum 158 1312-1318 F7.4 --- a159 ? Weight for eigenspectrum 159
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1 I1 --- Case [1/5] Case (1) 3- 20 A18 --- SDSS SDSS designation (HHMMSS.ss+DDMMSS.s)
Note (1): Cases as follows: 1 = Objects with no broad lines 2 = Objects with weak broad Hbeta 3 = Objects with anomalous [OIII] profiles 4 = Objects with anomalous Hbeta profiles 5 = Objects with miscellaneous anomalies
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 11-Jun-2012
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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