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J/ApJS/122/355 Properties of low z QSO absorption systems (Vanden Berk+, 1999)
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Clustering Properties of Low-Redshift QSO Absorption Systems Toward
the Galactic Poles
Vanden Berk D. E., Lauroesch J. T., Stoughton C., Szalay A. S.,
Koo D. C., Crotts A. P. S., Blades J. C., Melott A. L.,
Boyle B. J., Broadhurst T. J., York D. G.
<Astrophys. J. Suppl. Ser. 122, 355 (1999)>
=1999ApJS..122..355V
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ADC_Keywords: Equivalent widths; Galactic pole, north; QSOs;
Redshifts; Spectra, ultraviolet
Mission_Name: HST
Keywords: intergalactic medium - large-scale structure of universe
quasars: absorption line - ultraviolet: galaxies
Abstract (Partial):
We examine the clustering properties of low-redshift Ly{alpha} and
heavy-element QSO absorption line systems seen in the spectra of 13
QSOs at the Galactic poles. This is the densest sample of ~1 degree
separated QSOs observed spectroscopically with the Hubble Space
Telescope to date. At the median redshift of the Ly{alpha} sample
(z{=~}0.7), the QSO lines of sight are separated on transverse scales
from about 15 to 200h^-1^Mpc (q_0_=0.5, H=100h.km/s/Mpc),
allowing the three-dimensional clustering of the absorbers to be
examined on those scales. The Galactic poles are also regions where
relatively deep and wide-field galaxy redshift surveys have taken
place, so the distributions of galaxies and Ly{alpha} systems can be
compared within the same volume of space. There are 545 total
absorption lines detected in the complete sample from 13 QSOs. We
identify 307 Ly{alpha} systems, of which 18 contain heavy-element
lines. We confirm the relatively slow redshift number density
evolution for Ly systems at z{<=}1. There are also five likely C IV
doublets in our sample, for which the Ly{alpha} line is not
accessible.
Description:
All of the observations were made using the Hubble Space Telescope
Faint Object Spectrograph. Every QSO chosen for our program was
observed using the G190H grating, with a resolution of R{~=}1300, and
a wavelength coverage from about 1600{AA} to just above 2310{AA}. When
there was a sufficient difference between the estimated exposure time
needed for the G190H observations of a QSO, and the time used in the
total number of orbits needed to complete the observations, the G270H
grating setup was also used in the remaining time. Because the G130H
grating was never used, all observations were taken using the FOS Red
detector. The observations made for this program were taken in ACCUM
mode, in which the accumulated detector counts are read out and
recorded in intervals of about 2 minutes during each orbit. Two of the
archival spectra (B201 1257+34 and TON 153), were taken in RAPID mode,
in which the detector is read out in much shorter intervals.
Objects:
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RA (2000) DE Designation(s) (File)
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12 50 25.6 +30 16 39 B2 1248+30 = 4C 30.25 = QSO 1248+305 (table4.dat)
12 50 50.4 +31 25 53 CSO 173 = QSO 1248+3142 = QSO 1248+317 (table5.dat)
12 52 25.0 +29 13 21 CSO 176 = QSO 1249+2929 (table6.dat)
12 53 17.7 +31 05 50 CSO 179 = QSO 1250+313 = QSO 1250+3122 (table7.dat)
12 59 48.7 +34 23 22 B201 1257+34 = [B68b] 201 = 5C 12.121 (table8.dat)
13 08 29.7 +30 05 39 1306+3021 = CSO 825 = QSO 1306+3021 (table9.dat)
13 12 17.9 +35 15 21 PG 1309+355 = QSO 1309+355 = TON 1565 (table10.dat)
13 19 56.4 +27 28 09 TON 153 = QSO 1317+28 = QSO 1317+277 (table11.dat)
13 21 14.8 +28 47 49 TON 155 = CSO 878 = QSO 1318+2903 (table12.dat)
13 21 15.9 +28 47 19 TON 156 = CSO 879 = QSO 1318+290B (table13.dat)
13 23 20.7 +29 10 07 TON 157 = QSO 1321+294 = QSO 1321+2925 (table14.dat)
13 31 08.4 +30 30 33 3C 286 = 4C 30.26 = QSO 1328+3045 (table15.dat)
01 04 40.9 -26 57 08 CT 336 = [CT83] = QSO 0102.3-2713 (table16.dat)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 88 5 Line identifications for B2 1248+30
table5.dat 124 85 Line identifications for CSO 173
table6.dat 124 60 Line identifications for CSO 176
table7.dat 124 68 Line identifications for CSO 179
table8.dat 124 39 Line identifications for B201 1257+34
table9.dat 124 13 Line identifications for 1306+3021
table10.dat 124 38 Line identifications for PG 1309+355
table11.dat 124 80 Line identifications for TON 153
table12.dat 124 84 Line identifications for TON 155
table13.dat 124 16 Line identifications for TON 156
table14.dat 124 93 Line identifications for TON 157
table15.dat 124 52 Line identifications for 3C 286
table16.dat 124 21 Line identifications for CT 336
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See also:
VII/158 : Revised and Updated Catalog of Quasi-stellar Objects (Hewitt+ 1993)
Byte-by-byte Description of file: table*.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Num Line number
7- 13 F7.2 0.1nm Wave Observed wavelength of line (in vacuum)
19- 22 F4.2 0.1nm e_Wave Uncertainty of the wavelength position
24- 28 F5.2 0.1nm EW Equivalent width of the line
33- 36 F4.2 0.1nm e_EW Uncertainty of EW
38- 41 F4.2 0.1nm FWHM ? Full width half Maximum of the line
44- 47 F4.2 0.1nm e_FWHM ? Uncertainty of FWHM
49 A1 --- l_SL Limit on the SL
50- 54 F5.1 --- SL Significance level (1)
57 A1 --- f_SL [a] A SL < 4.5 line. Not in the complete
sample
63- 72 A10 --- ID Primary line identification
75- 78 I4 0.1nm wave ? Primary line wavelength identification
80 A1 --- f_ID [b] Identification highly uncertain
82- 88 F7.4 --- z ? Redshift from primary line
92-111 A20 --- ID2 Secondary line identification
113-116 I4 0.1nm wave2 ? Secondary line wavelength identification
118-124 F7.4 --- z2 ? Redshift from secondary line
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Note (1): The significance level is defined as the magnitude of the
estimated equivalent width divided by the interpolated uncertainty
in the equivalent width.
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History:
From ApJ electronic edition
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(End) Greg Schwarz (AAS) 04-Feb-2000