T HE A STROPHYSICAL J OURNAL S UPPLEMENT S ERIES,130:37è66,2000September
2000.The American Astronomical Society.All rights reserved.Printed in U.S.A.
(
A UNIFORM ANALYSIS OF THE Ly a FOREST AT z\0è5.I.THE SAMPLE AND DISTRIBUTION OF
CLOUDS AT z[1.7
J ENNIFER S COTT,1J ILL B ECHTOLD,1AND A DAM D OBRZYCKI2
Received1999January27;accepted2000April14
ABSTRACT
We present moderate-resolution data for39quasi-stellar objects(QSOs)at z B2obtained at the
Multiple Mirror Telescope.These data are combined with spectra of comparable resolution of60QSOs
with redshifts greater than1.7found in the literature to investigate the distribution of Ly a forest lines in
redshift and equivalent width.WeDnd a value for c,the parameter describing the number distribution of
Ly a forest lines in redshift,of1.88^0.22for lines stronger than a rest equivalent width of0.32in
A, good agreement with some previous studies.The Kolmogorov-Smirnov test was applied to the data,and
it is found that this single power law is a goodDt over the relevant redshift ranges.Simulations of the
Ly a forest were performed to determine the completeness of the line lists and to test how well the
analysis recovers the underlying line statistics,given this level of completeness.
Subject heading:quasars:absorption lines
On-line material:machine-readable table
1.INTRODUCTION
The spectra of quasi-stellar objects(QSOs)blueward of Ly a emission show a large number of absorption lines pri-marily due to Ly a absorption by intervening neutral hydro-gen along the line of sight to the QSO(Lynds1971;Sargent et al.1980;Weymann,Carswell,&Smith1981).The evolu-tion of the number density of these lines can be described by a power law in1]z with index c.It has been debated whether the number densities of absorbers of di?erent column densities,Ly a forest,Lyman limit systems,and damped Ly a systems,evolve di?erently with redshift which would indicate that these absorbing structures represent di?erent populations of objects(Lanzetta1991;Storrie-Lombardi1995;Storrie-Lombardi1994;Giallongo et al. 1996).
Several authors have carried out the analysis of the sta-tistics of the Ly a forest on other data sets(Lu,Wolfe,& Turnshek1991,hereafter LWT;Bechtold1994,hereafter B94;Williger et al.1994;Cristiani et al.1995;Giallongo et al.1996;Kim et al.1997;Weymann et al.1998).At high redshift,LWTDnd c\2.75^0.29;and B94,whose resolution class M sample is a subsample of our total sample,Dnds c\1.85^0.27.These results were obtained using aDxed equivalent width threshold of0.36and using
A
only Ly a lines outside the immediate vicinity of the QSO. Work with high-resolution spectra has yielded results similar to those of both LWT and B94.Cristiani et al.(1995)Dnd c\1.86^0.21for Ly a forest lines with log(N H I)o13.8from R D22,000spectra of three QSOs;and Giallongo et al.(1996)Dnd c\2.7for lines with from
log(N H I)Z14
R D25,000spectra of10QSOs.Similarly,Kim et al.(1997) report c\2.78from a sample of R D36,000spectra ofDve QSOs taken using the HIRES Spectrograph on the Keck Telescope.
The evolution is signiDcantly?atter at redshifts less than 1.7.TheDrst Hubble Space Telescope(HST)Quasar Absorption Line Key Project paper(Bahcall et al.1993) reported c\0.50^0.77for lines from13objects with
1Steward Observatory,University of Arizona,Tucson,AZ85721; https://www.doczj.com/doc/ff12343246.html,,jbechtold=https://www.doczj.com/doc/ff12343246.html,.W[0.32The addition of four more quasars at z\1.3 A.
yielded c\0.58^0.50for lines with W[0.24(Bahcall
A
et al.1996).Weymann et al.(1998)have analyzed the com-plete HST Key Project Ly a absorption line sample present-ed by Jannuzi et al.(1998).TheyDnd c\0.15^0.23for a Dxed equivalent width threshold of0.24From a large
A.
sample of archival HST/Faint Object Spectrograph(FOS) spectra which includes the public data from the Key Project,Dobrzycki&Bechtold(1997)Dnds c\0.87^0.27 for lines with W[0.36at z\1.7,and notes that this
A
value?attens to c\0.14^0.45for Ly a lines with equiva-lent widths between0.24and0.36This is supported by
A.
Weymann et al.(1998),who alsoDnd a trend of increasing c with increasing line strength.
In this paper,a homogeneous sample of moderate-resolution QSO spectra is used to investigate the number density evolution of Ly a systems and how this changes with redshift and with varying equivalent width thresholds.Spe-ciDcally,the Ly a forest in the redshift range between1.6and 2.0was targeted because few lines of sight in the literature cover this range,as it extends down to wavelengths of D3200Improvements in CCD technology allowed us to A.
obtain data in this spectral region.We present new data for 39objects and supplement this sample with60objects from the literature.Metal line systems in these spectra have been identiDed and removed from theDnal analysis of the Ly a forest(Murdoch et al.1986,hereafter MHPB).The resulting Ly a absorption line sample is comprised of2079lines in the range 1.6\z\4.1when a variable equivalent width threshold is used,or1131lines using aDxed rest equivalent width threshold of0.32Future papers will extend this
A.
work to the local universe using a sample of low-redshift spectra from the HST/Faint Object Spectrograph(FSO) archives.Much recent work has promoted treating the Ly a forest as density?uctuations in the continuousDeld of the intergalactic medium(Bi1993;Reisenegger&Miralda-1995;Hernquist et al.1996;et al. Escude Miralda-Escude 1996;Bi&Davidsen1997;Croft et al.1998,1999;Wein-berg et al.1999).However,in this paper,we will continue to interpret the Ly a forest as a series of discrete lines for com-parison to previous work.The spectra presented in this data
38SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
tions in the universe(Croft et al.1998,1999)and are avail-able on the web.For the spectra used in this paper,see the authors?homepages,which are accessible from either http:// https://www.doczj.com/doc/ff12343246.html, or https://www.doczj.com/doc/ff12343246.html,
In°2,the details of the observations are outlined and the absorption line sample is presented.Notes on individual sample QSOs and their corresponding absorption line systems are given in°3.In°4the statistics of the Ly a forest are derived and discussed.Ly a forest simulations based on our sample of QSOs were performed to test the ability of our analysis to recover the underlying line statistics in our moderate-resolution data.These are also presented and dis-cussed in°4.In a subsequent paper,Paper II in this series (Scott et al.2000),we will investigate the measurement of the mean intensity of the ionizing background radiation using this Ly a forest sample.
2.DATA
2.1.Observations and Data Reduction
A sample of39QSOs was observed using the Multiple Mirror Telescope and Blue Channel Spectrograph.The observations are summarized in Table1.Each object?s red-shift is given in column(3)and the reference for that redshift is given in column(4).
The three instrumental setups used are as follows:(1)the ““Big Blue??image tube and photon counting Reticon detec-tor,a832lines mm~1grating blazed at3900in the
A
TABLE1
S UMMARY OF QSO A BSORPTION L INE S PECTRA O BSERVATIONS
Alternate Total Exposure Wavelength
QSO Name z em References m
V a Instr.b Date(s)(A)
(1)(2)(3)(4)(5)(6)(7)(8)(9) 0006]020...... 2.34117.521993Nov1572003200è4088 0027]018......UM247 2.31218.911992Oct2536003136è4118 0037è018.......UM264 2.34118.021994Jan772003205è4109 0049]007......UM287 2.27317.811992Oct23è2596003150è4111 0123]257......PKS 2.37317.521993Nov1690003198è4094 0150è202.......UM675 2.14417.111992Oct24è2560003173è4126 0153]744......S5 2.34316.021993Nov1536003192è4088 0226è038.......PKS 2.07316.921993Nov1630003198è4095 0348]061...... 2.05417.611992Oct2524003130è4112 0400]258......B2 2.10118.021994Jan730003209è4121 0747]613...... 2.49117.511992Oct2536003323è4269 0836]710......S5 2.21316.521993Nov1536003192è4088 0848]155...... 2.01417.721993Nov1536003192è4088 0936]368......CSO233 2.02117.021994Apr436003176è4058 0952]338......CSO239 2.50117.021994Jan754003486è4389 0955]472......PC 2.48117.721994Jan736003486è4389 0956]122...... 3.30117.521994Jan736004394è5293 1009]299......CSO38 2.63116.021994Jan736003622è4525 1207]399...... 2.45317.531994Apr59003201è4824 1210]175...... 2.56117.421994Jun436003572è4453 1231]294......CSO151 2.01116.021994Mar1218003172è4053 1323è107.......POX188 2.36517.021994Jun454003200è4087 1329]412......PG 1.93116.321994Jun318003202è4087 1337]285...... 2.54117.121994Jun336003574è4455 1346è036....... 2.36317.221993Jul1836003275è4155 1358]115...... 2.58116.521993Jul1836003547è4424 1406]492......CSO609 2.16117.021994Jun3è434003201è4085 1408]009......UM645 2.26318.031994Apr59003200è4807 1421]330......Mrk679 1.90416.721994Jun418003200è4084 1422]231...... 3.62316.521993Jul16è1718004853è5716 1435]638...... 2.06315.021993Jul16è1772003100è3942 1603]383......HS 2.51616.941997Apr12è1333003532è5045 1604]290......KP63 1.96117.021993Jul1836003100è3943 1715]535......PG 1.93416.321993Jul16è1790003100è3938 2134]004......PKS 1.94117.511992Oct24è2572003173è4125 2251]244......PKS 2.35317.821993Nov16120003200è4093 2254]022......PKS 2.09417.021993Jul16è1772003100è3936 2310]385......UT 2.18317.511992Oct2512003200è4118 2320]079......PKS 2.08117.521993Jul1754003160è3940 2329è020.......UM164 1.89117.021993Jul1836003060è3943
a As listed in Hewitt&Burbidge1993,with the exception of1603]383for which V was calculated from the?ux-calibrated spectrum(unpublished).
b Instrument Setup:(1)Big Blue Reticon,832lines mm~1second order,1@@]3@@slit;(2)3K]1K CCD,832lines mm~1second order,1@@]180@@slit;(3)3K]1K CCD,800lines mm~1Drst order,1@@]180@@slit;(4)3K]1K CCD,1200lines mm~1Drst order,
3500
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1.5
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2.5
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3.5
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.39
second order with a red blocking Dlter,and a
CuSO 4
1@@]3@@slit;(2)the 3K ]1K CCD,the 832lines mm ~1grating blazed at 3900in the second order with a A CuSO
4order blocking Dlter,and a 1@@]180@@slit;and (3)the 3
K ]1K CCD,800lines mm ~1grating blazed at 4050in A the Drst order,and a 1@@]180@@slit.All these spectra have a spectral resolution of D 1with the exception of the A spectra of 1207]399and 1408]009taken with the 800lines mm ~1grating,which have a resolution of D 2.5A .Thinning and backside illumination of a Loral CCD along with the use of antire?ection coatings and backside surface charging (Lesser 1994)improved the quantum efficiency of the 3K ]1K CCD used to over 80%at 3200The A .exposures from the Drst runs using the improved CCD at the MMT su?er from a variable focus across the chip due to problems with the original Deld ?atteners used.Figure 1shows the FWHM of the comparison lamp lines as a func-tion of wavelength.The 1993July data were taken on the Drst run with this CCD detector;and a number of problems were encountered,including poor charge transfer efficiency and a jump in the bias level of D 8ADU in the center of the chip.On this run,the FWHM rises to D 2.5at the red end A of the spectrum (Fig.1,short -dashed line ).
Wavelength calibration was performed using He-Ne-Ar-Hg-Cd lamp exposures;and dome?ats or quartz exposures were used to correct for pixel-to-pixel variations.When available,a few half-hour exposures of each object are com-bined;and the total integration time is listed in Table 1.The QSO spectra are shown in Figure 2.
Cosmic rays were removed from the data during the reduction process.Bad columns on the CCD were left in the spectrum in order to keep track of their positions.The ?ux in these regions was set to a value of [1000.;and they were excluded from the analysis.In some spectra,some clearly non-Gaussian features are present at the red end,mainly
F I
G .1.èFWHM of comparison lines vs.wavelength for four separate
instrumental setups listed in Table 1:solid line ,(1)Big Blue Reticon,832lines mm ~1second order,1@@]3@@slit;short -dashed line ,(2)3K ]1K CCD,832lines mm ~1second order,1@@]180@@slit;dotted line ,same as redward of Ly a emission.Because these features occur at the same pixel in each of the spectra in which they are visible,they are identiDed as traps in the CCD.They are discussed individually in °3below.
2.2.L ine IdentiDcation Process
The continuum was Dt iteratively to each spectrum and signiDcant (3p or greater)absorption lines were found by measuring the equivalent width in bins of size equal to 2.46times the FWHM of the comparison lines in pixels,the point at which a Gaussian is 1.5%of its peak value (B94;Young et al.1979).Lines of 3p signiDcance and above were used to help identify metal line systems,but only lines of greater than 5p signiDcance were used in the analysis of the Ly a forest statistics.
Using the technique described in Dobrzycki &Bechtold (1996),we produced a set of 30simulated z \2.48pure Ly a forest spectra in order to determine how reliably our program for Dnding signiDcant lines,FINDSL,recovers those generated by the simulations.We use values of 1.82and 1.46for Ly a forest statistics c and b ,but the results of this analysis should not be sensitive to the value of c as the redshift path covered in each spectrum is small.The lower and upper column density limits chosen were 1]1012and 7]1014cm ~2,respectively;and the mean Doppler param-eter and width of the Doppler parameter distribution used were 28km s ~1and 10km s ~1.The column density limits were chosen to give the same total absorption in the simu-lated spectra as is seen in the spectrum of 0955]472,the object spectrum which served as the template for this series of simulations.
We determine matches between the simulation line list output and the FINDSL line lists on the basis of the best wavelength match between simulated and recovered lines.At 5p signiDcance,the line lists are 55%complete.When blending is accounted for by matching all simulated lines within 2.46resolution elements of each recovered line to that recovered line,99%of the lines in the simulation are recovered.These completeness values for 3p lines are 49%and 98%,respectively.Obviously,FINDSL can do nothing to help us overcome the Dnite resolution of the data,but when this is taken into consideration,this test indicates that it does a good job of recovering the lines it is capable of recovering.
Our simulations also revealed another interesting point.Of the 3p lines ““recovered ??by FINDSL,a small percent-age,D 0.25%,were not generated by the simulation program.In other words,FINDSL found some lines in the noise.This was not true of the 5p lines,however,so we expect no spurious lines to be present in the line lists used for the analysis of Ly a forest statistics.We do use lines with signiDcance levels between 3p and 5p for metal line identi-Dcation purposes;but expect that any low occurrence of spurious lines would have no e?ect on those identiDcations due to the all the constraints that were placed upon metal line matches to qualify as true metal line systems,which are discussed in more detail below.
The 1993July CCD data su?er from a gradient in the FWHM across the spectrum as discussed in °2,rising from D 1.1in the blue end to D 2.5in the red (Fig.1).This A A variation has some impact on how FINDSL identiDes sig-niDcant https://www.doczj.com/doc/ff12343246.html,ing a FWHM of 2.5for j [3700A A ,
3200
3300
3400
3500
3600
010*******Q0006+020
z=2.340
10
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3700
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100200300400500
40
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3200
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2463200
3300
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100200300Q0027+018
z=2.310
10
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3700
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60030
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3200
3400
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24683200
3300
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02040Q0037-018
z=2.341
3700
3800
3900
4000
4100
501001503600
3800
4000
0.5
11.53200
3300340035003600
100200
300
Q0049+007z=2.279
10
20
3700
3800
3900
4000
4100
20040060030
40
50
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3200
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4000
2468
103200
3300340035003600
100200
300Q0150-202z=2.148
10
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3700
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4000
4100
200400600800100040
50
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3200
3400
3600
3800
4000
0123
32003300340035003600
100
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Q0153+744z=2.341
10
37003800390040004100
200
400
600
20
30
3400360038004000
1
2
3
4
5
32003300340035003600
-20
20
40
Q0400+258z=2.108
37003800390040004100
50
100
150
37003800390040004100
2
4
6
8
3400350036003700
100
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Q0747+610z=2.491
1020
304050
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38003900400041004200
200
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708090100
110
120
130
140
34003600380040004200
0.2
0.4
0.6
0.8
32003300340035003600
100
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Q0836+710z=2.218
10
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3700380039004000
500
1000
40
50
60
32003400360038004000
2
4
3200
3300
3400
3500
3600
010*******
400Q0848+155
z=2.014
10
3700
3800
3900
4000
200400600
3200
3400
3600
3800
4000
1
2343200
3300
3400
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3600
50100150Q0936+368
z=2.025
10
3700380039004000
100200300
2030
3400
3600
3800
4000
0.5
11.523500
3600
3700
3800
3900
100200300400500Q0952+335
z=2.504
10
20
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4000
4100
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4300
5001000
5060
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0.63500
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100200300400500Q0955+472
z=2.482
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500100015002000
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0.40.60.84400
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02004006008001000Q0956+122z=3.30810
20
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4900
5000
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52000
200400600
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1304400
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0.253700
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50010001500Q1009+299
z=2.63310
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41004200430044004500
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2000300060
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3600
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0.06
0.080.10.120.140.16
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0100200300400Q1207+399
z=2.45910
20
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42004400460048000
20040060080050
603500
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0.5
11.522.53600
3700
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100200300400Q1210+175
z=2.564
10
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4100420043004400
20040060080060
70
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0.40.63200
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0100200300400500Q1231+294
z=2.018
10
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3700
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20040060050
3200
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0.40.60.83200
3300
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010*******Q1323-107z=2.36010
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100200300400500
60
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0.40.60.811.2
3200
3300340035003600
0200400600800Q1329+412z=1.934
1020
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3700
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20040060040
3200
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0.40.60.8
1
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100200300Q1346-036
z=2.362
10
3800
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4000
4100
20040060080020
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11.522.5
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100200300Q1358+115
z=2.58910
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1.53200
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010*******Q1406+492
z=2.16110
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3400360038004000
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4200440046004800
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234563200
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02004006008001000Q1421+330
z=1.905
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0.40.6
0.84900
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50010001500Q1422+231
z=3.623
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5300
5400
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56005700
0500100070
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0.60.8
3200330034003500
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Q1435+638z=2.066
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3600370038003900
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3200340036003800
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3200330034003500
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Q1604+290z=1.962
3600370038003900
100
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3200340036003800
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3200330034003500
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Q1715+535z=1.932
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3600370038003900
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3200340036003800
0.5
1
1.5
3200
3300340035003600
100
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Q2134+004z=1.941
10
37003800390040004100
100
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32003400360038004000
1
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010203040Q2310+385
z=2.181
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20406080
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11.522.53200
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z=2.088
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5010015020025010
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2468103200
330034003500
010*******Q2329-020z=1.896
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0501001502003200
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46846
SCOTT,BECHTOLD,&DOBRZYCKI
Vol.130
F I
G .2.èContinued
Inspection of the Dts for these two cases for several objects in our sample leads us to conclude that the two cases give consistent total equivalent widths for absorption features,but that using a search window based on a FWHM of 1.1A ,even at the red ends of these spectra,gives the most reason-able line identiDcations,as the larger window tended to blend distinct features together.Table 3gives a list of the vacuum,heliocentric wavelengths of all lines identiDed along with the equivalent width of each line as determined by a Gaussian Dt to the line.
We generated additional synthetic Ly a forest spectra with no metal lines in order to determine the maximum number of metal line identiDcations that our software will identify spuriously in the Ly a forest,or equivalently,the minimum number of metal line identiDcations needed to qualify as a metal line system,cf.Dobrzycki &Bechtold (1996).The simulation parameters used in this case were c \1.5,b \1.46,cm ~2,N lower \2]1012N upper
\1016
that may appear to be reasonable based on the species present and doublet ratios,if the number of required matches between the data and a table of possible metal lines is set to a number less than 4if there are less than D 100lines in the spectrum,and less than 5if there are more than D 100identiDed lines in the spectrum.If a system shows lines redward of Ly a emission,this requirement is relaxed since this spectral region is free of Ly a forest absorption lines.
The search list of metal lines,their wavelengths,and their f -values was taken from Table 4of Morton,York,&Jenkins (1988)supplemented with Fe II j 1143and j 1145and N I j 1135from their Table 3.Redshift systems were identiDed by Drst running our metal line searching program to Dnd systems with our prescribed number of matches.Metal line matches within 3p of an observed signiDcant line are counted.The output of this program was analyzed for consistency with required doublet ratios and f -values.Lines
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.47
TABLE2
QSO S PECTRA FROM THE L ITERATURE QSO z em Reference
(1)(2)(3) 0000[263...... 4.1111 0001]087...... 3.2431 0002]051...... 1.8992 0002[422...... 2.7633,4 0014]813...... 3.3841,5 0029]073...... 3.2941 0058]019...... 1.9596 0100]130...... 2.6904 0114[089...... 3.2051,5 0119[046...... 1.9377 0142[100...... 2.7276 0237[233...... 2.2226 0256[000...... 3.3741,5 0301[005...... 3.2231 0302[003...... 3.2861,5 0334[204...... 3.1261 0421]019...... 2.0512 0424[131...... 2.1666 0453[423...... 2.6563,4 0636]680...... 3.1741,5 0731]653...... 3.0331 0831]128...... 2.7391,5 0837]109...... 3.3266 0848]163...... 1.9256 0905]151...... 3.1731 0913]072...... 2.7841,5 0938]119...... 3.1921 1017]280...... 1.9286 1033]137...... 3.0921 1115]080...... 1.7252 1159]124...... 3.5026 1206]119...... 3.1081,5 1208]101...... 3.8221 1215]333...... 2.6061,5 1225[017...... 2.8311,5 1225]317...... 2.2004 1247]267...... 2.0396 1315]472...... 2.5901,5 1334[005...... 2.8421,5 1400]114...... 3.1771 1402]044...... 3.2061 1410]096...... 3.3131 1442]101...... 3.5541 1451]123...... 3.2511 1511]091...... 2.8786 1512]132...... 3.1201 1548]092...... 2.7481,5 1601]182...... 3.2271 1602]178...... 2.9891 1607]183...... 3.1341,5 1614]051...... 3.2161 1623]269...... 2.5261,5 1700]642...... 2.7441,5 1738]350...... 3.2391 1946]770...... 3.0205 2126[158...... 3.2804 2233]131...... 3.2951 2233]136...... 3.2091 2311[036...... 3.0411
R EFERENCES.è(1)Bechtold1994;(2) Young et al.1982a;(3)Sargent et al.1979;
(4)Sargent et al.1980;(5)Dobrzycki&line of a species is detected while a stronger line of the same species and ionization state is not(e.g.,Si II j1304is detected but Si II j1260is not).Next,lines with rest equiva-lent width greater than about1were tentatively identiDed
A
as Ly a for a metal line system.The resulting redshift was used as a trial redshift and the matches with metal lines were noted and critiqued as above.
A metal line system identiDcation is considered a strong one if it is corroborated by a spectrum from the literature that extends redward of Ly a emission.A system is con-sidered reasonable if it consists of at least the minimum number of lines and the strengths of those lines are in agree-ment with the expected f-values and range in doublet ratios. An identiDcation is marked as a possible identiDcation if either the doublet ratio gives a value less than1or greater than2,i.e.,one of the doublet lines is a blend if it is present, or if the separation between that line and another line in the redshift system(excluding doublet pairs)is greater than D200km s~1but less than D300km s~1.Once metal lines were identiDed,they were removed from the line list used for the Ly a forest analysis.Also,the redshift path covered by each line was removed from the analysis by removing a region of width2.5p centered on the wavelength centroid of the line.The line p and line centroid were taken from the GaussianDt.
The redshift of any spurious line in our3p line lists identiDed as a metal line would also have to match with other metal lines in our line list,speciDcally to a strong Ly a line if it is observable in the spectrum.For this reason,we expect that the possible low occurrence of false lines of less than5p signiDcance in our line lists has no e?ect on the metal line systems identiDed below.
3.NOTES ON INDIVIDUAL OBJECTS
3.1.Q0006]020,z em\2.340
This QSO was identiDed by Foltz et al.(1989).Tytler et al.(1993,hereafter T93),discuss the redshift systems they Dnd in their red(4312è7059low-resolution(8.6
A),A FWHM)spectrum of this object.We do not conDrm the Drst system theyDnd at This identiDcation was
z abs\1.131.
based on the detection of Mg II jj2796,2803at5960and 5975respectively,which we do not detect in our red A,
spectrum of this object,which is presented in Paper II of this series.The second system T93Dnd is at for
z abs\2.034 which they identify the C IV doublet at4700and Al II
A
j1670at5073The positions of Ly a and Si III j1206for A.
this redshift lie on bad columns in the data,but we identify N II j1083at3289a possible N V doublet at3757and
A,
3770Si II j1260at3825and C II j1334at4050In A,A,A. addition,our red spectrum of this QSO conDrms the C IV doublet and Al II identiDcations of T93while also revealing the Si IV doublet at4227and4252and a possible Si II
A
j1526line at4632Identifying the4700line in the
A.A
spectrum of T93as Si IV j1393reveals the third system,at We identify Ly b at3460O VI j1031and z abs\2.374.A,
j1037at3482and3501and N I j1200at4050Our red
A,A.
data conDrm the4700feature as well as the C IV doublet
A
at D5222for this redshift.This system is consistent with A
an associated absorber as proposed by Foltz et al.(1989). We also detect several other systems using the methods and criteria described above:
48SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
position of the j 1402component lies on a bad column but there is an absorption feature at this wavelength in our red spectrum),and Si II j 1526at 3984(which is blended with A Ly a at In addition,our red spectrum (see
z abs
\2.2775.)Paper II)shows a line at 4362consistent with Al II j 1670A ,for this redshift.
this redshift,we identify Ly a at 3427z abs \1.8189.èAt N I j 1200at 3383a tentative N V doublet at 3491and A ,A ,3501(where the j 1242component must be blended with A Ly a at and/or O VI j 1037at and
z abs \1.880z abs
\2.375),C II j 1334at 3762The C IV doublet at this redshift is A .visible in our red spectrum at a wavelength of 4367A .
this system,we detect Ly a 3454z abs
\1.8409.èFor A ,Si III j 1206at 3427Si II j 1260at 3579and C II j 1334A ,A ,at 3791Our red spectrum does not show any lines A .redward of Ly a consistent with this redshift.
system is composed of Ly a at 3501z abs \1.8802.èThis a N V doublet at 3568and 3579C II j 1334at 3845A ,A ,A ,and a possible weak Si IV j 1393line at 4015(no j 1402is A detected.)No lines redward of Ly a emission are detected in the red spectrum.
is a system showing Ly a at 3984z abs
\2.2775.èThis A ,Ly b at 3363Si III j 1206at 3955and the N V doublet at A ,A ,4060and 4072(The position of Fe II j 1145falls on a bad A .column for this redshift.)A possible C IV doublet identiDca-tion is made from the red spectrum at 5076A .
Finally,we Dnd a possible Mg II absorber at z abs
\0.448.
However,the implied Fe II lines are not consistent with line ratios.Therefore,since only two lines are found,this system cannot qualify as a metal line system by our criteria.3.2.Q0027]014,z em
\2.310
Steidel &Sargent (1992,hereafter SS92),Dnd a single Mg II system for this object at using their red setup
z abs
\1.2664(5128è8947with 4è6resolution.In addition to Mg II A )A jj 2796,2803(at 6336and 6352respectively),they iden-A ,tify Fe II j 2382at 5400We conDrm this system with our A .detection of the C IV doublet at 3508and 3513as well as A Al II j 1670at 3786Our red spectrum of this object (see A .Paper II)shows the Fe II line found by SS92but shows only marginal evidence for the Mg II doublet.
We also identify two other redshift systems in our spec-trum:
Dnd Ly a at 3454N I j 1200at 3411z abs \1.8415.èWe A ,Si III j 1206at 3428Si II j 1260at 3582a possible,A ,A ,A ,blended C II j 1334line 3793and the Si IV doublet at 3960A ,and 3986However,the doublet ratio for the Si IV doublet A .is greater than 2;therefore,the j 1393component must be blended.Our red spectrum shows Si II j 1526at 4337the A ,C IV doublet at 4403Fe II j 1608at 4572and Al II A ,A ,j 1670at 4748A .
for this possible system is found at z abs \1.9859.èLy a 3630At this redshift,we also identify N II j 1083,Fe II A .j 1145,Si II j 1193and j 1260lines at 3237,3419,3563,and 3763The equivalent widths relative to Ly a indicate each A .of these must be blended.A Si III j 1206line is found at 3603The red spectrum shows no lines for this redshift redward A .of Ly a emission.
3.3.Q0037[018,z em
\2.341
Wolfe et al.(1986,hereafter W86),Dnd a candidate damped Ly a system present in the spectrum of this object at However,since their objective was to search
(z abs
\2.152).for and characterize damped Ly a systems only,they do not produce detailed line lists for their spectra.These lines are not conDrmed by our data.We Dnd no signiDcant absorp-tion feature at 3602but we do Dnd a line at 3604We A ;A .also Dnd no signiDcant line at 3832Due to the low signal-A .to-noise at the blue end of our spectrum,we truncated the spectrum for the purposes of our line searches.The usable portion of our spectrum therefore extends from D 3542to D 4110The features at 3998,4003,4007,and 4011are A .A identiDed as traps in the CCD,as they appear in many other object spectra.
3.4.Q0049]007,z em
\2.279
We Dnd a system consistent with Ly a at 3540SS92(cf.A .°3.2)identify this metal line system at on the
z abs
\1.9115basis of weak Al III j 1854and j 1862lines and a weak Mg II doublet.Further corroboration of this system comes from a possible N V j 1238line at 3607(no j 1242is detected)and A the Si IV doublet at 4057and 4084respectively,in our A ,data.Our red spectrum of this object (see Paper II)also shows Si II j 1526at 4445and the C IV doublet at 4507A ,and 4515consistent with this system.
A ,In addition,we Dnd Dve other systems or possible systems from our data:
identify this system based on the C IV z abs \1.3865.èWe doublet at 3695and 3701We also Dnd Si II j 1526at 3643A .and Al II j 1670at 3987SS92do not Dnd a Mg II A ,A .doublet nor do they Dnd any Fe II lines at this redshift.Our red spectrum shows possible Al III j 1854and j 1862lines at 4426and 4445However,the feature at 4445is more A .A likely Si IV j 1393at z abs \2.1908.
system is composed of O I j 1302at z abs \1.5226.èThis
3285Si IV j 1393at 3515and j 1402at 3540(blended A ,A A with Ly a at a possible identiDcation of Si II
z abs
\1.9123),j 1526at 3850and the C IV doublet at 3905and 3912A ,A .SS92do not detect a Mg II doublet or any Fe II lines at this redshift,nor do we Dnd any matching lines in our red spec-trum.
is a relatively insecure identiDcation z abs
\2.1168.èThis based upon Ly a at 3789a possible O I j 1302at 4057A ,A and possible Si II j 1193and j 1260lines at 3720and 3927A .No lines are found redward of Ly a emission.
system shows Ly a at 3850Ly b at z abs \2.1667.èThis A ,3248and a very tentative N V doublet both components A ,of which must be blends at 3927and 3935We Dnd no A .lines at this redshift in our red spectrum.
this system,we Dnd Ly a at 3880z abs
\2.1918.èFor A ,Ly b at 3274Si III j 1206at 3850and a possible,A ,A ,blended N II j 1083at 3458In addition,our red spectrum A .shows the Si IV doublet at 4447and 4476and the C IV A doublet at 4944A .3.5.Q0123]257,z em
\2.370
The absorption spectrum of this QSO has been observed by Schmidt &Olsen (1968,hereafter SO68),Oemler &Lynds (1975,hereafter OL75),and W86(cf.°3.3).
We conDrm the absorption features seen by SO68at 3900,4013,4057,and 4065The remainder of their fea-A .tures lie outside the wavelength range of our spectrum.They report an absorption system at an
z abs
\2.3683,associated absorber,from the identiDcation of Ly a and the
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.49
only system theyDnd compelling,however,is the z abs\ 2.3683system of SO68.We conDrm several lines possibly associated with this system:Ly b at3456O VI jj1031,
A,
1037at3473and3496N II j1083at3645and Si III
A,A,
j1206at4064which is blended with Ly a at
A,z abs\2.3433. Our red spectrum of this object(see Paper II)shows the C IV doublet at5216and5226We also conDrm the
A.
absence of any marked damped Ly a absorption,as reported by W86.
We tested all of the possible redshift systems proposed by OL75and used our usual methods forDnding additional metal line systems.As a result,we identify three other systems:
system consists of Fe II j2600at z abs\0.3207.èThis
3433a Mg II doublet at3693and3702and Mg I j2753 A,A,
at3767A.
system consists of Ly a at3456
z abs\1.8427.èThis A, Si III j1206at3430O I j1302at3702and Si IV j1393
A,A,
at3962with a possible identiDcation of j1402blended A,
with a feature at3989A.
this system,weDnd Ly a at3693
z abs\2.0379.èFor A, Fe II j1143and a blended j1145at3473and3478and
A,
N I j1200at3645Neither SO68nor OL75note any
A.
absorption features at the position of Fe II j1608for this redshift;and our red spectrum shows no lines at this red-shift.
3.6.Q0150[203,z em\2.148
The absorption spectrum of0150[203(UM675)isDrst discussed in detail by Sargent et al.(1988,hereafter SBS88). Their data provide coverage from3815to5038with1.5
A A resolution.They report several absorption systems from their spectrum:
Mg II doublet is identiDed at this red-z abs\0.3892.èA
shift.SBS88report the possible blending of the Mg II doublet at with a second component at
z abs\0.3892z abs\ 0.3882.Our spectrum does show two prominent absorption features at3883and3896If these lines are interpreted as
A.
the Mg II doublet the resulting redshifts are z abs\0.38869 for the j2796line and for the j2803line,an
z abs\0.38977
unacceptable separation of233km s~1.It is possible to identify three Fe II lines at this redshift,j2344at3253A, j2382at3308and j2586at3590However,no Fe II
A,A.
j2600line is found,which calls the identiDcation of the j2344and the j2586lines into question.Given these argu-ments and the more compelling identiDcation of the3883 and3896features as the N V doublet at we
A z abs\2.134, consider this system improbable.
Mg II system showing Fe II j2382is z abs\0.7800.èA
reported by SBS88.The only lines in our search list that fall within the wavelength range of our data for z abs\0.7800 are Al III j1854and j1862,but we detect neither of these, and thus we cannot conDrm this system.
detect a weak C IV doublet at this z abs\1.7666.èSBS88
redshift.We conDrm this system from our detection of Ly a at3363and possible identiDcations of O I j1302at3604 A
and C II j1334at3693
A,A.
regard this weak C IV doublet as a z abs\1.9287.èSBS88
probable system.We conDrm this system through our iden-tiDcations of Ly a at3560and tentative Si II j1193,j1260,
A
and j1304lines at3494,3690,and3821respectively.
A,
2.0097.èSBS88regard this C IV complex z abs\2.0083,also identiDed for the component of this
z abs\2.0097
complex.We conDrm the system.At this red-
z abs\2.0083
shift,we identify lines of Ly a at3657Fe II j1145at3444
A,
Si II j1193at3590(possible),Si II j1260at3792N V A,A A,
j1238at3726(possible),and C II j1334at4014York
A A.
et al.(1991)give this component a B rating,as SBS88only identiDed the C IV doublet.For the com-
z abs\2.0097 ponent,we conDrm Ly a absorption at3659or
A,z abs\ 2.0101.We alsoDnd Fe II j1145at3446Si III j1206at
A,
3632and O I j1302at3918York et al.(1991)assign A,A.
this system an A rating since SBS88identiDed both C IV and Si IV j1393at this redshift.In our spectrum,the Ly a lines for the components of this complex are within5of a third
A
line,which,if identiDed as Ly a as well,gives z abs\2.0060. However,we detect only one other line(Si II j1260at3788 for this redshift.This,and the fact that SBS88Dnd no A)
C IV at lead us to regard this additional identi-
z abs\2.0060
Dcation as extremely uncertain.
SS92(cf.°3.2)Dnd no Mg II systems in their spectrum of this object although they note that for the SBS88systems at
1.9287,
2.0083,and2.0097,these lines would z abs\1.7666,
have been visible in their spectrum if present.In fact,SS92Dnd no absorption features in their spectrum at all.
Beaver et al.(1991,hereafter B91),observed the far-UV spectrum of this object using the FOS on the HST.The spectra range from1630to2428and were taken using
A
two di?erent apertures each resulting in D8.0resolution.
A
In addition,optical spectra were obtained with the Lick telescope.These spectra cover3250è6350at15
A A resolution and3540è4120at 1.8resolution.B91
A A
conDrm the system of SBS88with their identi-z abs\0.7800
Dcation of Ly a at2161and Ly b at1836as well as their
A A
tentative identiDcations of C II j1334at2370and Si III
A,
j1206at2148and their possible identiDcation of C III
A
j977at1736They also report one other system:
A.
optical spectra of B91show strong z abs\2.1348.èThe
absorption at3810which is identiDed as Ly a.This identi-
A,
Dcation results in the coincidence of the N V doublet at this redshift with the Mg II doublet at identiDed by
z abs\0.3892
SBS88.This system is corroborated by the tentative identiD-cation of Ne VIII j770at2417and the uncertain identiD-
A
cation of He I j584at1836We identify several lines for
A.
this associated absorber,including Ly a at3810O VI
A,
jj1031,1037at3234and3253N II j1083at3397and
A,A,
N V jj1238,1242at3883and3896Also,as noted by
A.
B91,the spectrum of SBS88shows some absorption near the position of the C IV doublet at this redshift(D4860A) but they do not identify this feature.
We identify one additional system in our data:
system consists of Fe II j2382,j2586, z abs\0.3628.èThis
and j2600at3249,3525,and3542respectively,as well as
A,
Mg II jj2796,2803at3810and3821B91do not detect
A.
Ly a for this system in their FOS spectrum,however,its position at1657would place it at the blue edge of their
A
data where the signal-to-noise ratio is poor.
3.7.Q0153]744,z em\2.341
According to our searches,there is no previously published spectrum of this QSO.In our spectrum,weDnd only one possible metal line system,an associated absorber at We consider this identiDcation tentative, z abs\2.3456.
50SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
detected are O VI j1031and j1037at3453and3472Fe II
A,
j1143and Fe II j1145at3826and3831and Si III j1206
A,
at4037In addition,our red spectrum(see Paper II)does A.
show a possible C IV doublet at5179and5188but the
A, doublet ratio is less than1.
3.8.Q0226[038,z em\2.073
The absorption line spectrum of this QSO has been studied by many authors.TheDrst such investigation was undertaken by Carswell et al.(1976)using spectrograms spanning a wavelength range from3200to6000Young,
A. Sargent,&Boksenberg(1982b,hereafter YSB82)obtained spectra from3530to5070with2.2resolution.In addi-
A A
tion,Lanzetta,Turnshek,&Wolfe(1987,hereafter LTW87) obtained spectra from6271to8766with4.5resolution
A A
and a signal-to-noise ratio between18and32.This object was also observed by SS92with their red setup and by SBS88(cf.°3.2and°3.6).
The spectrum we obtained for this object is,unfor-tunately,riddled with bad columns from the CCD.There-fore,weDnd no absorption systems from our data alone; instead,we use our spectrum to attempt to conDrm the systems found by other authors:
conDrm the Mg II identiDcation for z abs\1.3284.èSS92
this system which was found by LTW87.SS92also identify Fe II j2344,j2382,and j2600in their red spectrum.They further corroborate this system by noting that lines found by YSB82at3606and3611can be identiDed as the C IV
A
doublet and that an unidentiDed line found by SBS88at 3890can be identiDed as Al II j1670.Our data show the A
C IV j1548line at3604but weDnd only a weak feature at
A,
the expected position of j1550.The position of Al II j1670 falls on a bad column in our data.There is a feature at3555 the expected position of Si II j1526;but it is not identiDed A,
as a signiDcant line as it falls on another of the many bad columns.
propose the identiDcation of two z abs\1.3558.èYSB82
lines,at3647and3654in the Ly a forest region of their
A,
spectrum with the C IV doublet at this redshift.We conDrm the presence of these lines;however,given the lack of any other lines to strengthen this identiDcation,the does not meet our criteria for a true metal line system.
identify this system based on the z abs\2.0435.èSBS88
identiDcation of the Si IV and C IV doublets.The expected position of Ly a for this redshift falls on a bad column in our data;and weDnd only one other possible line for this red-shift,Si III j1206at3672A.
We do not conDrm the absorption line at3703reported
A
by Carswell et al.(1976).
3.9.Q0348]061,z em\2.056
SBS88(cf.°3.6)Dnd several absorption systems in their spectrum of this QSO(3880è5060A):
system is a single Mg II doublet z abs\0.3997.èThis
according to SBS88.WeDnd only marginal evidence for a Mg II doublet at3912and3921from our red spectrum of
A
this object(see Paper II).
Dnd a C IV doublet at this redshift. z abs\1.7975.èSBS88
We verify Ly a absorption at3400we detect a possible Si
A;
III j1206line at3374and our red spectrum shows the
A;
C IV doublet identiDed by SBS88at4328and4336A.
Dnd another C IV doublet at this z abs\1.8409.èSBS88found for this redshift;and our red spectrum corroborates
the C IV doublet found by SBS88as well as showing Si IV
j1393at3958(but no j1402)and a possible Si II j1526
A
line at4335A.
Dnd a C IV doublet along with C II z abs\1.9681.èSBS88
j1334and a possible Si IV j1393line at this redshift.We Dnd Ly a3608Si III j1206at3581and a very tentative A,A,
N V doublet at3676and3687which,if present,is highly
A,
blended with Ly a at and Our
z abs\2.0238z abs\2.0331.
red spectrum veriDes the identiDcations of SBS88listed
above and also shows Fe II j1608at4775A.
Dnd a C IV doublet and possible z abs\2.0237.èSBS88
Si IV j1393at this redshift.SS92(cf.°3.2)conDrm this
system in their red spectrum(5128è8947of this object
A)
with the detection of a Mg II doublet at this redshift.They
do not detect Mg II for any of the other SBS88redshifts to
which their spectrum is sensitive We detect
(z abs[0.83).
Ly a absorption at3676in agreement with this system.In
A,
addition,we identify a possible blended Si II j1193line at
3608N I j1200at3628Si III j1206at3648Si II A,A,A,
j1260at3812and C II j1334at4035Our red spec-
A,A.
trum exhibits the features found by SBS88listed above as
well as C II j1334at4037A.
identify both C IV and Si IV doub-z abs\2.0330.èSBS88
lets for this redshift.We detect Ly a at3687and Si III
A
j1206at3659Our red spectrum shows marginal evi-
A.
dence for the features listed by SBS88.
3.10.Q0400]258,z em\2.108
No previously published absorption line spectrum of this
QSO was found in our searches.Unfortunately,the low
signal-to-noise of the blue portion of our spectrum(3208è
3659prevents us from identifying any lines in the Ly a A)
forest.WeDnd only one signiDcant line at3752from
A
which we cannot identify any metal line systems.
3.11.Q0747]610,z em\2.491
In their catalog of QSO absorption lines,Junkkarinen,
Hewitt,&Burbidge(1991)note two metal line systems
found for this object by Afanasjev et al.(1979).These
systems were identiDed at and
z abs\1.986z abs\2.210. York et al.(1991)give both of these systems a B rating in their reference catalog of heavy element systems in QSO spectra.According to their explanation of their rating system,this B rating indicates that either a C IV or Mg II doublet was identiDed for these systems with the correct doublet ratio,but that no other lines but Ly a were detected. However,Junkkarinen et al.note that for the z abs\1.986 system,N V,Si II,C II,Si IV,and Al II lines were detected in addition to H I and C IV;and for the system,Si
z abs\2.210
II*,N V,C II,Si IV,and Al III lines were detected in addition to H I and C IV.SS92(cf.°3.2)do not conDrm either of these metal line system redshifts.Instead,theyDnd three others at
and
z abs\1.1282,z abs\2.0076,z abs\2.4865.
We conDrm the system of Afanasjev et al.
z abs\1.986
(1979)with our identiDcation of Ly a at3629a possible
A,
N I j1135at3389a possible Si II j1190line at3554
A,A,
Si II j1193at3562and N I j1200at3582We also
A,A.
conDrm their system with our detection of Ly a z abs\2.210
at3903a possible N II j1083line at3480Si III j1206at A,A,
3874Si II j1260at4047and O I j1302at4180 A,A,A.
We do notDnd any lines at the position of the z abs\
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.51
accordance with the system found by these
z abs\2.0076
authors.At this redshift,weDnd a strong Ly a line at3656A, Si II j1190and j1193at3580and3589Si III j1206at
A,
3629Si II j1260and j1304at3791and3923O I j1302 A,A,
at3915and possible C II j1334absorption at4014It A,A. is clear that some of these Si II lines are blends given their relative strengths.Our conDrmation of the z abs\2.4865 system of SS92is not as strong.WeDnd Ly a and Ly b at 4237and3575respectively,for this redshift.But we do
A,
not detect any other species with any conDdence.
The absorption line spectrum of this object is a rich one. WeDnd a total of145signiDcant lines,and weDnd12metal line systems in addition to the ones discussed above.As is the case for all of our objects,it is unlikely that all of these systems are real since SS92do not report any lines from their red spectrum at these redshifts.However,we have kept all the systems that cannot be deDnitively ruled out on the basis of our data.For all redshifts below1.742,the Ly a line falls outside the spectral range of our data.The values of these redshifts are based upon the strongest line that was detected for each system.
system is based upon a C IV doublet z abs\1.4102.èThis
at3731and3738and a Si IV doublet at3359and3381
A A. We alsoDnd Al II j1670at4028A.
value for this redshift is based upon a z abs\1.4529.èThe
C IV doublet at3798and3804In addition,we detect Si IV
A.
j1393at3419and Si IV j1402at3441(though it must
A A
be a blend if it is present otherwise the Si IV doublet ratio is less than1),Si II j1526at3745and Al II j1670at4098
A,A.
this system,we identify Si II j1304at z abs\1.5986.èFor
3389possible C II j1334absorption at3466a possible A,A,
Si IV j1393line at3621(no j1402is found),Si II j1526at
A
3967and a possible,weak C IV j1548line at4023A A,A. weak feature is present at the position of C IV j1550,but it is not identiDed as a signiDcant(3p)line.
redshift is based upon Si II j1260. z abs\1.6822.èThis
We alsoDnd a possible blended N V j1242line at3333A (j1238is out of the wavelength range of our line list),O I j1302at3492Si II j1304at3498C II j1334at3580
A,A,A, and a rather doubtful Si IV doublet at3738and3761A.
system,based on a possible C IV z abs\1.7324.èThis
doublet at4230and4237is a relatively tentative one due
A,
to the inconsistent doublet ratios of this pair and of a pos-sible Si IV doublet at3808and3833We alsoDnd O I
A.
j1302at3558A.
this system,weDnd Ly a at3419In z abs\1.8123.èFor A. addition,weDnd a possible Si II j1193line at3357Si III
A,
j1206at3393a possible blended Si II j1260line at3544 A,
O I j1302at3662and C II j1334at3753
A,A,A.
system consists of Ly a at3492
z abs\1.8728.èThis A, Si II j1190and j1193at3419and3428N I j1200at
A A,
3447Si III j1206at3466a possible N V j1238line at A,A,
3558Si II j1260at3621C II j1334at3833and a A,A,A, possible Si IV j1393at4003(no j1402component is
A
found).
2.009
3.èWeDnd a metal line system of two z abs\2.0070,
components at these redshifts.TheDrst component shows Ly a at3656Si II j1190and j1193at3580and3589a A,A, possible Si III j1206line at3618Si II j1260and j1304at
A,
3791and3923C II j1334at4014and Si IV j1393at
A,A,
4192The j1402component of this doublet is blended A.
with the same line corresponding to the other system at found),Si II j1260at3792C II j1334at4015and a
A,A, tentative Si IV doublet at4194and4221(with a doublet
A
ratio less than1due to blending).
system is composed of Ly a at3705 z abs\2.0476.èThis
N I j1200at3656(blended with Ly a at if A,A z abs\2.007 present),Si III j1206at3677O I j1302at3967and
A,A,
Si IV j1393at4247A.
this redshift,we identify Ly a at3816 z abs\2.1391.èAt
N I j1135and j1200at3562and3767and a possible A,A,
N V doublet at3889and3901for which the j1242com-
A
ponent must be blended as it is stronger than both the j1238component of the doublet and Ly a.
system consists of Ly a at3856
z abs\2.1724.èThis A, tentative N I j1135and j1200lines at3601and3808A, Si III j1206at3828and a possible C II j1334line at4235
A,
A.
system is identiDed on the basis of z abs\2.2849.èThis
strong Ly a absorption at3993Ly b at3369O VI j1031
A,A,
and j1037at3389and3408possible Si II j1190and
A,
j1193lines at3777and3786and a possible Si III j1206
A,
line at3964A.
3.12.Q0836]710,z em\2.218
Stickel&(1993)report an absorption feature in Ku hr
their spectrum of this object at5360which they identify
A
as the Mg II doublet at WeDnd Al III j1854at
z abs\0.914.
3550Also,we have a red spectrum of this object in the A.
vicinity of Mg II emission.This spectrum does show the Mg II doublet at5359and5372giving a redshift of0.916.
A,
WeDnd several other redshift systems in our data:
system is a double-component C IV z abs\1.4256.èThis
absorber with the Si IV doublet at3380and3403the C IV
A, doublet at3755and3762a possible Si II j1526at3702
A,A, and Fe II j1608at3902Two components in each line are
A
evident in the spectrum,with the second,weaker com-ponent at which,unlike theDrst component, z abs\1.4249
shows Al II j1670absorption,at4051A.
this redshift,we detect absorption z abs\1.6681.èAt
from Ly a at3243C II j1334at3561and a Si IV
A,A,
doublet at3719and3742(though its implied doublet
A
ratio is less than1).There is no Mg II absorption in our red spectrum.
system consists of Ly a at3322O I z abs\1.7331.èThis A,
j1302at3558the N V doublet at3386and3397and a A,A, possible Si IV j1393line at3809The expected position of
A.
the Mg II doublet falls on a poorly subtracted sky line in the red spectrum.
WeDnd a two-component associated absorption system at consisting of only Ly a(3866and Ly b z abs\2.1800A)
(3261and3263A).
The absorption features at3964,3970,3975,and3983A are identiDed as traps in the CCD.
3.13.Q0848]153,z em\2.014
YSB82(cf.°3.8)Dnd eight absorption lines blueward of Ly a emission in their spectrum of this QSO.They do not identify any of them.SBS88(cf.°3.6)detect only one line in their spectrum of this object(one which is not found by YSB82.)SS92(cf.°3.2)Dnd four absorption features in their red spectrum and identify three of them as a Mg II doublet and Fe II j2600at Neither we nor YSB82nor
z abs\1.0254.
SBS88observed the region of the spectrum necessary to conDrm the C IV doublet for this system;but we do identify
52SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
that lines8and11in our line list match the position of the Si IV doublet at well,although we cannot call
z abs\1.5738
this a true metal line system based on our criteria.
3.1
4.Q0936]368,z em\2.025
We have found no previously published spectrum of this object.Due to low signal-to-noise in the blue region of our spectrum(3200è3400the spectrum was truncated at
A)
roughly3400for the purposes of the line list.The absorp-A
tion features at3942,3948,and3955are traps in the
A
CCD.
The only system found is a C IV doublet at4001and4006 and C II j1334at3448from a system at
A A z abs\1.5841.
3.15.Q0952]335,z em\2.504
Our spectrum of this object shows a damped Ly a system at3765with an observed equivalent width of30.97The
A A. absorption features at4277,4282,4286,and4290are
A traps in the CCD.WeDnd10possible metal line systems:
system consists of several Fe II lines z abs\0.5393.èThis
(j2344at3609j2374at3655j2382at3668j2586
A,A,A,
at3981and j2600at4002and a possible Mg II A,A)
doublet at4304and4314However,these Mg II lines are
A.
weaker than all of the Fe II lines identiDed,contrary to what is expected;and the relative strengths of the Fe II lines are also not entirely consistent with the expected values. Although the possibility of blending keeps us from ruling out this system altogether,it is a tentative one.
redshift is based upon a C IV j1548 z abs\1.5362.èThis
line at3927The expected position of C IV j1550for this A.
redshift falls on a bad column in the data.We also detect a Si IV doublet at3535and3558Si II j1526at3872Fe II
A,A,
j1608at4079and Al II j1670at4237
A,A.
this system,weDnd Ly a at3695
z abs\2.0399.èFor A, Si III j1206at3668C II j1334at4055and the Si IV
A,A,
doublet at4237and4265Also,the position of the N V
A.
doublet falls within the damped Ly a line at3763A.
for this system is found at3714
z abs\2.0555.èLy a A. We also identify Fe II j1145absorption at3498possible
A,
Si III j1206absorption at3687possible Si II j1260and
A,
j1304absorption at3850and3985and a Si IV doublet at
A,
4258and4286A.
system is the damped Ly a absorber z abs\2.0965.èThis
noted above.The metal lines found at this redshift include Si II j1190and j1193at3685and3695(possible),a N I
A
j1200line at3714Si III j1206at3735Si II j1260at
A,A,
3903C II j1334at4130and Si IV jj1393,1402at4314 A,A,
and4342A.
this system,weDnd Ly a at3850
z abs\2.1670.èFor A, Fe II j1143and j1145at3620and3626N I j1200at3801
A,
and Si III j1206at3820
A,A.
system consists of Ly a at3872
z abs\2.1850.èThis A, Si II j1193at3801N I j1200at3820Si II j1260and
A,A,
j1304at4014and4153and O I j1302at4147
A,A.
this redshift,we detect Ly a at3903
z abs\2.2102.èAt A, Si II j1190and j1193at3820and3830Si III j1206at
A,
3872a possible N V j1238line at3976(no j1402 A,A component is found),a blended Si II j1260line at4046A, and O I j1302at4180The expected position of Si II
A.
j1304falls on a bad column in the data.
this system,we identify Ly a at4002 z abs\2.2924.èFor
system consists of Ly a at4035
z abs\2.3189.èThis A, Fe II j1143and j1145at3795and3801Si II j1193at
A,
3959and Si II j1260at4183
A,A.
3.16.Q0955]472,z em\2.482
We note the presence of associated absorption in the spectrum of this radio loud QSO,at4203,4206,4219,and 4241separated from the position of the Ly a emission by A,
2121km s~1,1910km s~1,990km s~1,and[539km s~1, respectively.We do notDnd metal line systems consistent with these redshifts,but we doDnd Ly b absorption in our spectrum for theDrst,third,and fourth systems listed above at3547,3561,and3579The Ly b line for the second
A.
system appears to be blended with Ly b for theDrst system at3549but is not identiDed as a signiDcant line by our A
line-Dnding program.The metal line systems weDnd are as follows:
system is identiDed on the basis of a z abs\1.7251.èThis
possible C IV doublet at4219and4225The other metal
A.
lines detected are O I j1302at3547and Si II j1304at
A
3554This system is relatively insecure.
A.
this system,weDnd Ly a at3993
z abs\2.2849.èFor A, N II j1083at3561blended N I j1200absorption at3943
A,
Si III j1206at3963and a possible N V doublet for A,A,
which the j1238component is blended with the Ly a complex at4071and the j1242component is detected at
A,
4082A.
2.3481.èLy a for this system is part of the z abs\2.3453,
Ly a complex at4067Other lines detected include a pos-
A.
sible,blended N I j1135line and N I j1200at3796and4014 Fe II j1145at3830Si II j1190and j1193at3984and A,A,
3993Si III j1206at4038and a possible N V doublet at A,A,
4144and4156A.
system consists of Ly a at4144N I z abs\2.4087.èThis A,
j1135and j1200at3869and4090and Si III j1206at
A,
4112Despite the fact that the putative N I j1135line A.
shows good redshift agreement with this system,it is treated as a possible identiDcation because the stronger line of the same species,N I j1200,shows poorer agreement.
The absorption features at4277,4282,4286,and4290A are traps in the CCD.
3.17.Q0956]122,z em\3.308
Sargent,Steidel,&Boksenberg(1989)obtained a spec-trum of this object with4resolution from3150to4700
A A and6resolution from4600to7000TheyDnd weak
A A.
C IV systems at and WeDnd
z abs\2.9145z abs\3.2230.
only Ly a at The system at is z abs\2.9156.z abs\3.2230 identiDed as a Lyman limit system by Steidel(1990)from a higher resolution(D1.1spectrum.He identiDes C IV and
A)
Si IV doublets,Si III j1206,C III j977and several Lyman series lines.We conDrm this system with our detection of Ly a at5134N I j1200at5069and Si III j1206at5095 A,A,
Songaila&Cowie(1996)identify this system as a partial A.
Lyman limit system at Sargent et al.(1989)
z abs\3.2216.
alsoDnd a Lyman limit system with no corresponding heavy element lines at We identify strong Ly a
z abs\3.096.
absorption at this redshift as well as a possible Si II j1260 line at5162Both of these lines are found in the spectrum A.
of Steidel(1990),but they are not attributed to a Lyman limit system.Instead,Steidel(1990)Dnds another Lyman
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.53
j1260falls on a trap in the CCD.Several other metal line systems were also found by this author:
spectrum does not extend far enough z abs\0.0456.èOur
into the red to allow us to conDrm the Na I jj5891,5897 lines tentatively identiDed at this redshift.
(1990)tentatively identiDes Ly a, z abs\2.3104.èSteidel
C IV j1548,and Al II j1670at this redshift.WeDnd C II j1334at4418a double-component Si IV doublet at4614 A,
and4636Si II j1526at5054and C IV j1548and j1550 A,A,
(blended with Ly a at at5125and5134Hu
z abs\3.223)A,
et al.(1995)identify this double-component Si IV doublet as well in a high-resolution(D0.13spectrum taken with the
A)
HIRES Spectrograph on the Keck Telescope.The j1393 line is seen at and
z abs\2.3104z abs\2.3109.
(1990)Dnds C II j1334,a C IV z abs\2.7169.èSteidel
doublet,and Al II j1670at this redshift.We conDrm this system with the detection of Ly a at4519N I j1200at
A,
4461Si III j1206at4484the N V doublet at4604and A,A,
4618and C II j1334at4959The position of O I j1302 A,A.
falls on a bad region in the spectrum.
(1990)Dnds a weak C IV doublet z abs\2.7261.èSteidel
at this redshift.We do notDnd Ly a corresponding to this redshift.
(1990)Dnds a weak C IV doublet z abs\2.8320.èSteidel
at this redshift as well as Ly b,Si II j1260,and C II j1334.We identify Ly a at4659N I j1200at4599Si II j1260at
A,A,
4830a possible Si II j1304line at5002(blended with A,A
Ly a at z\3.1145),O I j13024990and a possible C II
A,
j1334line at5118A.
(1990)identiDes Ly a,C III j977, z abs\3.1045.èSteidel
and the C IV doublet for this secure system.We conDrm strong Ly a absorption at4990andDnd a Si II j1260line
A
at5172A.
(1990)Dnds a weak C IV doublet,a z abs\3.1530.èSteidel
Si IV doublet,Si II j1190and j1193,Si III j1206,and several Lyman series lines.We detect Ly a at5048a possible N I
A,
j1200line at4980(blended with Ly a at a
A z abs\3.0963), tentative Si III j1206line at5012and the N V doublet at
A,
5144and5157We detect the features identiDed by
A.
Steidel(1990)as Si II j1190and j1193,but since our spec-trum shows no feature at the position of Si II j1260,we do not conDrm those identiDcations.
We identify several other possible metal line systems from our spectrum:
system is separated by172km s~1 z abs\2.8342.èThis
from the system found by Steidel(1990)at z abs\2.8320. Ly a is detected at4661the N V doublet at4750and4765
A,
and Si II j1260at4832The Si II j1304and C II j1334 A,A.
identiDed with the system are more likely
z abs\2.8320
associated with this system.
system consists of Ly a at4922
z abs\3.0490.èThis A, possible Fe II j1143and j1145lines at4630and4636A, Si III j1206at4884and Si II j1260at5103Steidel
A A. (1990)Dnds no line which would correspond to Fe II j1608 at D6510or C IV at D6270
A A.
this redshift,we identify Ly a at4927 z abs\3.0528.èAt
N I j1135and j1200at4599and4862Si III j1206at A,A,
4890and the N V doublet at5021and5036There is a A,A.
line in the Steidel(1990)line list at6274which would
A, correspond to C IV j1548at this redshift,but none at6285 which would correspond to C IV j1550.
A,
system is composed of Ly a at5023 z abs\3.1321.èThis ponents of which are blended with other lines(see line list), at5118and5134and Si II j1260at5208No C IV is
A,A.
detected by Steidel(1990).
this redshift,we detect Ly a at5103
z abs\3.1975.èAt A, N I j1200at5036Si III j1206at5065and a possible
A,A,
N V doublet at5200and5217A feature at6497in the
A.A
line list of Steidel(1990)would correspond to C IV j1548at this redshift,but no j1550component is present.
system consists of Ly a at5162
z abs\3.2461.èThis A, Fe II j1143and j1145at4855and4862N I j1135and
A,
j1200at4753and5095and Si III j1206at5122Steidel
A,A. (1990)Dnds no C IV doublet or Fe II j1608at this redshift.
this redshift,we identify Ly a at5200 z abs\3.2774.èAt
N II j1083at4636N I j1135and j1200at4855and A,A,
5134and Si III j1206at5162Steidel(1990)Dnds no A,A.
C IV at this redshift.
The absorption features at5176,5181,5185,and5189A are identiDed as traps in the CCD.
3.18.Q1009]299,z em\2.633
There are no previously published absorption line spectra of this object.From our data,weDnd eight candidate metal line systems including a complex of associated absorption near the quasar redshift:
system is identiDed by the C IV z abs\1.8484.èThis
doublet at4410and4418the j1550component of which
A,
is blended with Ly a at Other lines found
z abs\2.6339.
include O I j1302at3709Si II j1304and j1526at3715
A,
and4349A.
this system,we identify Ly a at3964 z abs\2.2611.èFor
Si III j1206at3934Si II j1260at4110O I j1302at A,A,A,
4246and a possible C II j1334line at4353The A,A. expected positions of Fe II j1143and j1145fall on bad columns in the data.
system is comprised of Ly a at4082 z abs\2.3582.èThis
N I j1200at4030Si III j1206at4052Si II j1260at A,A,A,
4232and O I j1302at4373
A,A.
this redshift,we detect Ly a at4110
z abs\2.3809.èAt A, N II j1083at3665N I j1200at4056Si III j1206at
A,A,
4079a possible N V j1242line at4201(the expected A,A
position of the j1238component falls on a bad region in the spectrum),and O I j1302at4403A.
this system,we identify very strong, z abs\2.4068.èFor
weakly damped Ly a absorption at4141Si II j1190at
A,
4056(the position of Si II j1193falls on a bad region in A
the spectrum),N I j1200at4087Si III j1206at4110
A,A, Si II j1260at4294and O I j1302at4436The position
A,A.
of Si II j1304falls on a bad column.
this redshift,we identify Ly a at4283 z abs\2.5236.èAt
N I j1135at3998Si II j1193at4205N I j1200at A,A,A,
4227and Si III j1206at4252The expected position of A,A.
Si II j1260falls on bad columns in the data.
system consists of Ly a at4319
z abs\2.5531.èThis A, Ly b at3645O VI j1031and j1037at3667and3686
A,A, N II j1083at3851Fe II j1143at4061(the position of
A,A
j1145falls on bad columns in the spectrum),and Si II j1193 at4240A.
this associated absorber,Ly a is z abs\2.6158.èFor
found at4396Ly b at3709C II j1036at3746
A,A,A, possible Fe II j1143and Fe II j1145blended with Ly a at at4134and4141and Si III j1206at4362 z abs\2.40677A,
A.
54SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
3.19.Q1207]399,z em\2.459
According to our literature searches,there is no pre-
viously published absorption line spectrum of this QSO.
From our data,weDnd two metal line systems:
this redshift,we detect a blended Ly a z abs\2.1116.èAt
line at3781Si III j1206at3765Si II j1260at3922
A,A,A,
C II j1334at4152Si IV jj1393,1402at4337and4365
A,A,
and a possible C IV j1548line at4816The expected
A.
position of C IV j1550for this redshift falls just outside our
spectral range.
this redshift,weDnd Ly a at3837
z abs\2.1561.èAt A, Ly b at3238Si III j1206at3808the N V doublet at A,A,
3907and3922Si II j1260at3977and C II j1334at
A A,A,
4212A.
The absorption features present at4576,4587,4595,and
4603are traps in the CCD.
A
3.20.Q1210]175,z em\2.564
This QSO was observed by Foltz et al.(1987),who noted
a possible damped Ly a system in their spectrum at roughly
3500According to Wolfe et al.(1995)this system is a A.
conDrmed damped Ly a absorber with an equivalent width
of11.3Ly a for this candidate is not within our spectral A.
range for this object.However,weDndDve metal line
systems from our data,one of which is consistent with this
damped system.
system is the damped Ly a absorber z abs\1.8917.èThis
discussed above.Ly a at this redshift is outside our spectral
range,but we do detect the Si IV doublet at4030and4056
Other lines detected include Si II j1260,j1304,and j1526 A.
at3645,3772,and4414O I j1302at3765and C II
A,A,
j1334at3859A.
this redshift,we identify Ly a at3713 z abs\2.0548.èAt
Si II j1193,j1260,and j1304at3645,3850,and3985 A,A, and C II j1334at4076The Si II j1304line must be a
A.
blend if it is present.
this system,we detect Ly a at3798
z abs\2.1240.èFor A, Si III j1206at3768a N V doublet at3868and3881a
A,A,
possible Si II j1260line at3938and C II j1334at4169
A,A.
this system,we identify Ly a at3887 z abs\2.1974.èFor
N I j1200at3837Si III j1206at3859Si II j1260at A,A,A,
4030O I j1302at4164and C II j1334at4266 A,A,A.
system consists of Ly a at4350
z abs\2.5786.èThis A, Ly b at3671and O VI j1031and j1037at3693and3714 A,
Both O VI lines are stronger than Ly a and Ly b indicating A.
either that they are blends or that the line of sight through
this absorber intersects regions dominated by highly
ionized gas.The latter interpretation is likely because the
redshift of this absorber is larger than the QSO emission
redshift,indicating that this absorbing material must be
infalling gas associated with the QSO itself.
3.21.Q1231]294,z em\2.018 Thompson,Djorgovsky,&Weir(1989)measure an emis-sion redshift of for this QSO from
z em\2.011^0.001
[O IV]]Si IV jj1397è1406and C III]j1909emission lines.
Our spectrum of Ly a emission gives a redshift of D2.018.
WeDnd two metal line systems from our absorption line
spectrum.
system consists of the C IV doublet z abs\1.4780.èThis
at3836and3843and the Si IV doublet at3454and3477
A
A.possible Fe II j1145line at3292and O I j1302at3745
A,A, blended with C IV j1550at z abs\1.4145.
Finally,we identify a C IV doublet at and a
z abs\1.4145
C IV doublet at along with Al II j1670at3621
z abs\1.1672
though we detect no other lines at these redshifts.The A,
absorption features at3937,3942,3946,and3950are
A traps in the CCD.The feature at3722is spurious as well,
A
and it most likely a cosmic ray.
3.22.Q1323[107,z em\2.360
The only previously published spectrum found for this object is a spectrum including Ly a and C IV emission from Kunth,Sargent,&Kowal(1981).TheyDnd an emission redshift of2.360for the QSO.WeDnd four candidate metal line systems from our absorption line spectrum:
system is based upon the Si IV z abs\1.4244.èThis
doublet at3379and3401At this redshift,we also detect
A.
C II j1334at3235and Si II j1526at3701No C IV
A A.
doublet is detected.
system is identiDed by the C IV z abs\1.4727.èThis
doublet at3828and3835Other lines detected include
A.
O I j1302at3220and C II j1334at3300
A A.
system is based upon the C IV z abs\1.4922.èThis
doublet at3858and3864Due to the large uncertainty in
A.
the position of the line center for the j1550component,the redshifts of the doublet components agree to within less than1p.We also detect O I j1302at3246possible Si II
A,
j1304and j1526lines at3250and3803respectively,and
A,
Fe II j1608at4008Our red spectrum of this object(see
A.
Paper II)actually extends slightly blueward of 1.0A resolution blue spectrum and shows a possible Si II j1260 line at3144A.
system consists of Ly a at3454N I z abs\1.8415.èThis A,
j1135and j1200at3225and3409a possible O I j1302
A,
line at3701Si II j1260and j1304at3582and3706
A,A, respectively,and C II j1334at3792The Si II j1260line
A.
must be blended because its equivalent width is larger than that of Ly a.The N I and Si II line matches have been retained despite poor redshift agreement between the two lines of the same species due to the fact the errors in the line centers of lines32(N I j1200)and64(Si II j1260)are large enough for these redshifts to agree to within D3p.Our red spectrum shows no lines redward of Ly a for this system.
3.23.Q1329]412,z em\1.934
SBS88(cf.°3.6)Dnd six absorption line systems in their spectrum of this object.SS92(cf.°3.2)conDrm two of these systems andDnd another.These are the systems these authors report and the additional information gained from our spectrum:
regard this system as probable z abs\0.5009.èSBS88
from their identiDcation of the Mg II doublet.The only search lines that fall in our spectral range for this redshift are Fe II jj2344è2600.WeDnd none of these.
system is identiDed by SS92from a z abs\1.2821.èThis
strong Mg II doublet.The spectrum of SBS88did not cover the region of C IV absorption,but ours does and weDnd no signiDcant lines that would correspond to the C IV doublet at this redshift.
system is identiDed by SBS88on the z abs\1.4716.èThis
basis of an??unambiguous??C IV doublet.SS92Dnd no Mg II absorption at this redshift.We conDrm the C IV
No.1,2000UNIFORM ANALYSIS OF THE Ly a FOREST.I.55
Dnd a strong C IV doublet at this z abs\1.6010.èSBS88
redshift which they note is likely to be blended with another C IV doublet at a nearby redshift.SS92identify the Mg II doublet at this redshift.Our spectrum shows the strong C IV doublet found by SBS88in addition to Si II j1260at3279A, C II j1334at3471and the Si IV doublet at3625and3648
A,
In addition,weDnd that the position of the C IV j1548 A.
for corresponds to a signiDcant line in our z abs\1.5980
spectrum,while the j1550component at this redshift appears to be strongly blended with C IV j1548at z abs\ 1.6007.
system is identiDed by SBS88by the z abs\1.8359.èThis
C IV doublet and conDrmed by SS92whoDnd the Mg II doublet at We detect Ly a at3447a pos-z abs\1.8355.A,
sible Fe II j1145line at3246possible Si II j1193and
A,
j1260lines at3384and3575and C II j1334at3785
A,A.
system is identiDed by SBS88on the z abs\1.8401.èThis
basis of a C IV doublet.SS92do not detect Mg II.We do detect a strong Ly a line consistent with this redshift at 3453A.
identify this system on the basis of z abs\1.9406.èSBS88
the C IV doublet.SS92do not observe the spectral region encompassing Mg II at this redshift;but we detect Ly a at 3575and a N V doublet at3643and3654This system,
A A.
having a redshift larger than the QSO emission redshift,is probably associated with the QSO.
The absorption features at3969,3974,3979,and3983A are traps in the CCD.
We detect a possible C IV doublet redward of Ly a emis-sion but blueward of the spectral range of SS92at a redshift of1.35285.The components are detected at3643and3648 along with Fe II j1608at3785The j1548component A A.
of the doublet coincides with N V j1238at z abs\1.9404; and the j1550component coincides with the Si II j1402for the well-established system at described
z abs\1.6010
above.No other lines are found.Also,weDnd another pos-sible C IV doublet in the Ly a forest at but no
z abs\1.2480;
other lines are detected at this redshift either.
Finally,Lanzetta,Wolfe,&Turnshek(1995b)report a damped Ly a system at in the IUE spectrum of
z abs\0.5193
Lanzetta,Turnshek,&Sandoval(1993).Again,the only lines in our spectral range for this redshift are Fe II jj2344è2600.We detect only the strongest of these lines,Fe II j2382 at3621A.
3.2
4.Q1337]285,z em\2.541
Our literature search yielded no previously published optical spectrum of this QSO.From our spectrum,we detect two possible heavy metal absorption systems:
relatively secure system consists of z abs\2.5081.èThis
Ly a at4265Ly b at3598possible O VI j1031and A,A,
j1037lines at3619and3640C II j1036at3636N II
A,A,
j1083at3803a possible Fe II j1145line at4017and A,A,
Si II j1190and j1193at4176and4186A.
this system,we detect Ly a at4283
z abs\2.5228.èFor A, Ly b at3614O VI j1031at3636possible N I j1135and A,A,
j1200lines at3998and4226Fe II j1143and j1145at
A,
4027and4033and Si III j1206at4249
A,A.
The absorption features at4339,4344,4347,and4352A are traps in the CCD.
3.25.Q1346[036,z em\2.362tion features seen by these authors with the exception of the line they detect at3844which falls on a bad region in our
A
spectrum.TheyDnd no metal line absorbers from their data, but suggest a possible Mg II doublet at We
z abs\0.4453. detect this tentative doublet at4043and4054A(z abs\ 0.4458)butDnd no Fe II absorption at this redshift.We detect the4051line reported by YSB82,but identify Mg II
A
j2803with the absorption feature at4054for better red-
A
shift agreement.
LTW87(cf.°3.8)report no absorption features in their red(6250è8350spectrum of this object.And W86(cf.
A)
°3.3)Dnd no damped Ly a candidates in their3200è5200A spectrum.
The only additional identiDcations we make for this object are two Ly a-Ly b pairs at3965and3345A(z abs\ 2.2616)and at4028and3450For the
A(z abs\2.3630).
pair,the Ly b line is stronger than Ly a and z abs\2.2616
must be a blend;also,our red spectrum(see Paper II)shows the C IV doublet for this system at5050and5058The
A.
redshift is larger than the QSO emission red-z abs\2.3630
shift indicating that it must be associated with the QSO, although not an associated absorber per se,as it shows no metal lines Our red spectrum does not show the C IV doublet at this redshift.
3.26.Q1358]115,z em\2.589
W86(cf.°3.3)Dnd several4p absorption features in their 10resolution spectrum of this object.We conDrm these A
lines with the exception of the features they report at3573, 3874,and4092We also conDrm the feature they report at
A.
4074having less than4p signiDcance.
A
WeDnd six possible metal line systems from our data:
system is a Mg II absorber for which z abs\0.5084.èThis
the doublet is detected at4218and4228The j2803
A. component of the doublet is blended with Ly a at z abs\ 2.4778.We also detect Fe II j2382and j2600at3593and 3922and Mg I j2853at4303
A A.
system is composed of a strong Ly a z abs\2.4158.èThis
line at4152possible Si II j1190and j1193lines at4065 A,
and4075a N I possible j1200line at4098and Si III A,A,
j1206at4121The expected position of N I j1135for this A.
redshift falls on a bad column in the data.
this system,weDnd Ly a at4323
z abs\2.5559.èFor A, Ly b at3647Si II j1190and j1193at4234and4243
A,A, N I j1200at4266and Si III j1206at4290
A,A.
system is composed of Ly a at4331 z abs\2.5630.èThis
Ly b at3655and Si II j1190and j1193at4241and A,A
4251The Si II j1193line is blended with Ly a at
A.z abs\
2.4968.
this redshift,weDnd an associated z abs\2.5763.èAt
absorber showing Ly a at4348Ly b blended with the
A,
feature at3672(Ly b at O VI j1031and
A z abs\2.5799),
j1037at3689and3709A.
system is another associated z abs\2.57996.èThis
absorber for which we identify Ly a at4353Ly b at3672
A,
and O VI j1031and j1037at3694and3714
A,A.
3.27.Q1406]492,z em\2.161
Literature searches yielded no previously published absorption spectrum of this QSO.From our data,weDnd two possible heavy element absorption systems:
redshift is based upon the C IV z abs\1.4330.èThis
56SCOTT,BECHTOLD,&DOBRZYCKI Vol.130
blend(possibly with Si IV j1393at due to its
z abs\1.4474) equivalent width relative to the j1393component and its poor redshift agreement with it.
system is another C IV absorber for z abs\1.4470.èThis
which the C IV doublet is found at3788and3795We also
A.
Dnd C II j1334at3266the Si IV doublet for which the
A,
j1393component lies at3411and the j1402component
A
is blended with the feature at3435Si II j1526at3736
A,A, and Fe II j1608at3936A.
A C IV doublet is found at and weDnd a
z abs\1.5253;
Ly a,Ly b pair due to an absorber at The
z abs\2.1540. absorption features present at3962,3967,3968,3974,3978, and3981are traps in the CCD.
A
3.28.Q1408]009,z em\2.260
According to a literature search,this is theDrst published spectrum of this object.Five possible metal line systems are found:
system is identiDed by a Si IV z abs\1.3158.èThis
doublet at3228and3248as well as Si II j1526absorption
A
at3535and a Fe II j1608line at3725
A A.
system is a C IV absorber with j1548 z abs\1.5190.èThis
identiDed at3900and j1550at3906Also found are
A A.
C II j1334at3363and Si II j1526at3843
A A.
system consists of Ly a at3274
z abs\1.6929.èThis A, Si III j1206at3248Si II j1260at3394and O I j1302
A,A,
at3506Despite the fact that this Ly a line is relatively A.
strong all of the other lines identiDed are (EW0\1.153A)
stronger,creating the need to invoke the possibility of blending for all of them.For this reason,this system is considered uncertain.
this redshift,we detect Ly a at3642
z abs\1.9956.èAt A, N I j1200at3595Si II j1260and j1304at3774and3906
A,
and O I j1302at3900
A,A.
this system,we identify Ly a at3889 z abs\2.1991.èFor
a blended Ly
b line at3282Si III j1206at3859and A,A,A,
Si II j1260at4032A.
The absorption features at4575,4586,4602are traps in
A
the CCD.
3.29.Q1421]330,z em\1.905
The rest-UV absorption spectrum of this object has been studied by many authors.Weymann et al.(1979)Dnd C IV in their2.5resolution spectrum at but not the
A z abs\1.462,
expected Si IV and C II absorption.This redshift is con-Drmed by Koratkar,Kinney,&Bohlin(1992)and by our data.WeDnd Si IV at3433and3455and C IV at3813and
A
3820A.
Uomoto(1984)Dnds several tentative systems in his red spectrum of this QSO:
(1984)detects a Mg II doublet at z abs\0.2249.èUomoto
this redshift.Our spectrum shows this identiDcation to be unlikely given the implied velocity separation of the doublet lines(D310km s~1)if they are associated with the features at3428and3433in our data.
A
(1984)Dnds a Mg II doublet at z abs\0.3236.èUomoto
this redshift.Our spectrum does not show these lines,nor any others at this redshift.
(1984)Dnds several Fe II lines at z abs\0.9030.èUomoto
this redshift,j2344,j2374,j2382,j2586,and j2600.Also, Mn II j2594and a Mg II doublet are detected.This Mg II A
(1984)Dnds a Mg II doublet at z abs\1.1732.èUomoto
this redshift which is conDrmed by SS92.WeDnd Si II j1526
at3318but no C IV or Al III.
A;
(1984)Dnds a C IV doublet at z abs\1.2252.èUomoto
this redshift.We detect absorption at the position of the
j1548component,but none at the position of j1550.
Foltz et al.(1986)Dnd four additional systems in their1A
resolution spectrum covering3820è4035A:
Mg II doublet is detected at this red-z abs\0.4565.èA
shift.These lines should fall at the very red edge of our
spectrum.While there are some possible features present,
we are not able to conDrm this system.
C IV doublet is detected at this redshift. z abs\1.5847.èA
We detect O I j1302at3368C IV j1548at4001and an
A,A,
apparent absorption feature,but no signiDcant line,at the
position of C IV j1550.
et al.(1986)Dnd a C IV doublet and z abs\1.7177.èFoltz
Al II j1670at this redshift.We conDrm this system with our
detections of Ly a at3304Si III j1206at3279and O I
A,A,
j1302at3539A.
et al.(1986)detect a C IV doublet at z abs\1.7590.èFoltz
this redshift.We detect a Ly a line consistent with this
system at3355A.
Caulet(1989)detects C IV at four redshifts including
and(see above).The other z abs\1.7171z abs\1.4621
systems detected are and for
z abs\1.7010z abs\1.7755 which we detect no Ly a absorption.
Finally,Lanzetta et al.(1995a)report a possible Lyman
limit absorber in their IUE spectrum at We
z LLS\1.4798.
Dnd possible absorption features at the positions of O I
j1302,Si II j1304,and Si II j1526for this redshift.These features are not identiDed as3p lines by FINDSL,however.
We do not detect C IV,Si IV,or C II.
The absorption features at3967,3972,and3980are
A
traps in the CCD.
3.30.Q1422]231,z em\3.623
This object is a gravitationally lensed quasar(Bechtold&
Yee1995,hereafter BY95.)Therefore,due to uncertainties
in the ampliDcation by the lensing,it will only be used for
the analysis of the Ly a forest statistics and not in the prox-
imity e?ect analysis in Paper II.
Bechtold&Yee(1995)obtained a spectrum of this object
from4818to5684with1.8resolution using the Sub-
A A
arcsecond Imaging Spectrograph on the Canada-France-
Hawaii Telescope.A red spectrum from6246to7179A
with2.0resolution was also obtained in order to identify A
metal line systems using the Red Channel Spectrograph on
the Multiple Mirror Telescope.The systems identiDed by
these authors are as follows:
system is identiDed by a strong C IV z abs\3.091.èThis
doublet.We detect a marginally consistent doublet at6323
and6331in our red spectrum(see Paper II).BY95also A
Dnd Ly a,Si II j1193,N I j1200,Si II j1260,and O I j1302.
We conDrm the Ly a feature at4973andDnd features at
A
4882,4907,5157,and5328in marginal agreement with
A,
the other lines found by these authors.No Si II j1190is
detected by us or BY95.The O I j1302line,if present,is
blended with Ly a at z abs\3.3830.
system is also based upon a strong z abs\3.382.èThis
C IV doublet seen in the red spectrum of BY95.These
authors also identify Ly a and Si II j1260blended with a