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J/ApJ/613/129          Equivalent widths of QSOs                   (Wise+, 2004)

Variability of narrow, associated absorption lines in moderate- and low-redshift quasars. Wise J.H., Eracleous M., Charlton J.C., Ganguly R. <Astrophys. J., 613, 129-150 (2004)> =2004ApJ...613..129W
ADC_Keywords: QSOs ; Equivalent widths ; Redshifts ; Spectra, ultraviolet Keywords: accretion, accretion disks - galaxies: active - quasars: absorption lines - quasars: general Abstract: We present the results of a search for variability in the equivalent widths (EWs) of narrow, associated (|Δv|≤5000km/s) absorption lines found in the UV spectra of z≤1.5 quasars. The goal of this search was to use variability as a means of identifying absorption lines arising in gas that is intrinsic to the quasar central engine. We have compared archival Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) spectra of quasars with recent spectra obtained as part of our own snapshot survey of the same objects with the Space Telescope Imaging Spectrograph (STIS). The intervals between observations are 4-10yr. We primarily focused on the C IV absorption lines, although we also studied other lines available in the same spectra (e.g., Lyα, N V, O VI). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 137 337 Line Identifications and Equivalent Width Measurements
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 14 A14 --- Name Quasar name 16- 22 F7.5 --- z Redshift 24- 30 F7.2 0.1nm l(STIS) ? STIS observed wavelength in Angstroms 32 A1 --- l_EW(STIS) Limit flag on EW(STIS) 33- 37 F5.2 0.1nm EW(STIS) ? STIS equivalent width in Angstroms 39- 43 F5.2 0.1nm e_EW(STIS)p ? STIS Poisson noise uncertainty in Angstroms (1) 45- 48 F4.2 0.1nm e_EW(STIS)c ? STIS continuum fit uncertainty in Angstroms (1) 50 A1 --- f_l(STIS) STIS blend flag (2) 52- 58 F7.2 0.1nm l(FOS) ? FOS observed wavelength in Angstroms 60 A1 --- l_EW(FOS) Limit flag on EW(FOS) 61- 66 F6.2 0.1nm EW(FOS) ? FOS equivalent width in Angstroms 68- 71 F4.2 0.1nm e_EW(FOS)p ? FOS Poisson noise uncertainty in Angstroms (1) 73- 76 F4.2 0.1nm e_EW(FOS)c ? FOS continuum fit uncertainty in Angstroms (1) 78 A1 --- f_l(FOS) [o] Indicates FOS values out of range 80 A1 --- l_DEW Limit flag on DEW 81- 85 F5.2 0.1nm DEW ? Difference between FOS and STIS equivalent widths in Angstroms 87 A1 --- l_DEW/sig Limit flag on DEW/sig 88- 92 F5.2 --- DEW/sig ? Deviation normalized to error (3) 94 A1 --- f_DEW/sig [u] Indicates a variable absorption line 96-100 A5 --- Line Line identification 101-102 A2 --- f_Line Flag on Line (4) 104-110 F7.2 0.1nm Wave ? Adopted rest wavelength in Angstroms 112 A1 --- f_Wave [ae] Flag on Wave (5) 114-118 F5.2 0.1nm Dlambda ? Difference between observed and expected wavelength in Angstroms 120-126 F7.5 --- zAbs ? Redshift of the absorption-line system 128-133 I6 km/s DVel ? Velocity offset of an absorption line (6) 135 A1 --- f_DVel [u] Indicates variable absorption for DVel
Note (1): The uncertainty is broken up into two parts, which should be added in quadrature to give the final error bar on the equivalent width. Note (2): A S indicates that the line listed in the STIS column is a known blend and the EW given is the total EW of the blend. In the same row, under the FOS column, we give the sum of the EWs of the individual lines making up the blend, as measured in the FOS spectrum. The rows below the total EW row in the FOS column give the EWs of the individual lines. These lines are identified with increasing index numbers in column 5. The corresponding rows in the STIS column are left blank. Note (3): The error bar was computed by adding all the relevant error bars in quadrature. (sig)2 = (eEW(STIS)p)2+(eEW(STIS)c)2+(eEW(FOS)p)2+(eEW(FOS)c)2 See text for more details. Note (4): Flag on Line is defined as follows: b = The Si IV (1393) line at zAbs=1.009 in the spectrum of EX 0302-223 is contaminated by Galactic Mg II (2803). c = The Lyα line at zAbs=1.125 in the spectrum of QSO 0957+561A is contaminated by Galactic Fe II (2586). d = In the case of PG 1241+176, the Galactic Fe II (2344) line and the O VI (1032) line at zAbs=1.2735 are blended in both the STIS and FOS spectra. f = The C IV doublet at zAbs=0.2014 in the spectrum of PKS 2135-14 is slightly contaminated by the Galactic Al II (1863) line. g = The observed lines at 2376 and 2384 in the spectrum of MRC 2251-178 are unidentified. However, they are contaminated by the Galactic Fe II (2344 and 2374), respectively. u = variable absorption line. Note (5): Flag on Wave has the following meaning: a = Mean wavelength of doublet; adopted when the doublet is unresolved in both the FOS and STIS spectra. e = In the case of PG 1718+481, the O VI (1037) and Fe II (2344) lines appear to be blended with neighboring unidentified lines in both the STIS and FOS spectra. Note (6): A positive velocity offset indicates a redshift of the absorption line relative to the quasar. These velocities are based on wavelengths measured from the FOS spectra whenever possible.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 16-Feb-2005
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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