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 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 2007 1540 Eigenspectra
table2.dat 1318 9800 Reconstruction weights for the QSO Sample
table3.dat 20 114 Outliers
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength of center pixel (Å)
8-2007 200F10.6 --- E Value of eigenspectrum (1 to 200 pixel)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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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
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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
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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
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1 I1 --- Case [1/5] Case (1)
3- 20 A18 --- SDSS SDSS designation (HHMMSS.ss+DDMMSS.s)
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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
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 11-Jun-2012