J/ApJ/759/112 The UV low-redshift intergalactic medium (Tilton+, 2012)
The low-redshift intergalactic medium as seen in archival legacy HST/STIS and
FUSE data.
Tilton E.M., Danforth C.W., Shull J.M., Ross T.L.
<Astrophys. J., 759, 112 (2012)>
=2012ApJ...759..112T 2012ApJ...759..112T
ADC_Keywords: Active gal. nuclei ; Spectra, ultraviolet ; Redshifts ;
Equivalent widths
Keywords: cosmological parameters; cosmology: observations;
intergalactic medium; quasars: absorption lines; ultraviolet: general
Abstract:
We present a comprehensive catalog of ultraviolet (HST/STIS and FUSE)
absorbers in the low-redshift intergalactic medium (IGM) at z<0.4. The
catalog draws from much of the extensive literature on IGM absorption
and reconciles discrepancies among several previous catalogs through a
critical evaluation of all reported absorption features in light of
new HST/COS data. We report on 746 H I absorbers down to a rest-frame
equivalent width of 12mÅ over a maximum redshift path length
Δz=5.38. We also confirm 111 O VI absorbers, 29 C IV absorbers,
and numerous absorption lines due to other metal ions. We characterize
the bivariate distribution of absorbers in redshift and column density
as a power law, (∂2N/∂z∂N)∝N-β,
where β=2.08±0.12 for O VI and β=1.68±0.03 for H I.
Utilizing a more sophisticated accounting technique than past work,
our catalog accounts for ∼43% of the baryons: 24±2% in the
photoionized Lyα forest and 19±2% in the warm-hot IGM as
traced by O VI. We discuss the large systematic effects of various
assumed metallicities and ionization states on these calculations, and
we implement recent simulation results in our estimates.
Description:
The primary scientific goal of this catalog is to create the most
comprehensive low-redshift IGM census possible with legacy STIS and
FUSE data. Therefore, we included all 44 sight lines with zAGN≲0.5
for which STIS/E140M and/or FUSE data were available at reasonable
quality. All data have a resolution of 20km/s or better at a
signal-to-noise ratio per resolution element (S/N)res≳5 in most
cases. The FUSE data provide wavelength coverage over 905-1187Å,
while, in most cases, STIS/E140M covers 1162-1729Å.
The data were supplemented by HST/COS data (1135-1770Å at a
resolution of ∼17km/s) in a few cases to assist in the confirmation
and interpretation of absorption features as described in Section 2.2,
though no measurements come from the COS data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 60 44 AGN sightlines and data used in the catalog
table4.dat 138 2947 InterGalactic Medium absorption line properties
table5.dat 89 1748 InterGalactic Medium absorber properties
refs.dat 76 26 References
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
VI/129 : The FUSE Observation Log (FUSE, 1999-2007)
J/ApJ/740/91 : Lyα & OVI in galaxies around quasars (Prochaska+, 2011)
J/ApJ/729/87 : SiIV absorption systems (Cooksey+, 2011)
J/ApJ/710/613 : Broad HI absorbers (Danforth+, 2010)
J/ApJ/708/868 : CIV candidates (Cooksey+, 2010)
J/ApJS/177/39 : Survey of low-redshift OVI absorbers (Tripp+, 2008)
J/ApJ/679/194 : Low-z intergalactic medium. III. (Danforth+, 2008)
J/ApJ/676/262 : PKS1302-102 intergalactic absorption system (Cooksey+, 2008)
J/ApJS/164/1 : IGM absorbers toward HE 0226-4110 (Lehner+, 2006)
J/ApJ/643/680 : Imaging & spectroscopy around PKS 0405-123 (Prochaska+, 2006)
J/ApJ/636/631 : Lyman-alpha forest toward PKS 0405-123 (Williger+, 2006)
J/ApJ/617/718 : Atomic data and EW for PKS 0405-123 (Prochaska+, 2004)
J/ApJS/155/351 : Absorption toward PG 1116+215 (Sembach+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name AGN sightline designation
13- 14 I2 h RAh Hour of right ascension (J2000)
16- 17 I2 min RAm Minute of right ascension (J2000)
19- 22 F4.1 s RAs Second of right ascension (J2000)
24 A1 --- DE- Sign of declination (J2000)
25- 26 I2 deg DEd Degree of declination (J2000)
28- 29 I2 arcmin DEm Arcminute of declination (J2000)
31- 32 I2 arcsec DEs Arcsecond of declination (J2000)
34- 39 F6.4 --- z [0.01/0.58] AGN redshift
41- 44 F4.1 ks STIS [4/96]? STIS/E140M exposure time
46- 50 F5.1 ks FUSE [4/669] FUSE exposure time
52- 55 F4.1 ks G130M [0.6/23]? COS/G130M exposure time
57- 60 F4.1 ks G160M [0.5/17]? COS/G160M exposure time
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Sight line identifier
13- 19 F7.2 0.1nm lambda [920.2/1772] Observed wavelength λ (Å)
21- 28 F8.5 --- z [0.002/0.5] Redshift
30- 42 A13 --- Line Identified line transition
44- 46 I3 --- Ion [1/300] Ion code (G1)
49 A1 --- f_EW [<>n~] Flag on EW (G2)
51- 56 F6.1 0.1pm EW [0/3959] Rest-frame equivalent width (in mÅ)
58- 62 F5.1 0.1pm e_EW [0/302] Uncertainty in EW
64- 67 F4.1 0.1pm EWd Mean Absolute Deviation (MAD) EW (1)
69- 79 A11 --- r_EWd ? Reference(s) for EWd (G3)
82 A1 --- f_b [n~] Flag on b (G2)
84- 88 F5.1 km/s b [0/167] Doppler b-parameter
90- 93 F4.1 km/s e_b [0/81] Uncertainty in b
95- 98 F4.1 km/s bd Mean Absolute Deviation b-parameter (1)
100-107 A8 --- r_bd ? Reference for bd (G3)
109-115 F7.1 --- Wmin The Wmin quantity (2)
117-136 A20 --- ALine Alternate line identification
138 A1 --- COS [adp] Flag indicating inconsistencies (3)
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Note (1): Used to generate that consensus value.
Note (2): Defined in Eq. 1 as:
Wmin=(4λ/7200(S/N)λ)(1+z)-1
This quantity roughly corresponds to a 4σ significance level
in equivalent width for the data in the rest frame of the absorber.
Features with equivalent widths near or below the reported value of
Wmin should be viewed with skepticism and treated as upper limits.
See section 2.2 for further explanations.
Note (3): Inconstitencies between the COS data (where available) and the
STIS and/or FUSE data:
* No flag if COS data are absent or in agreement with the other data
* "a" indicate features that are entirely absent from the COS data
* "p" indicate features weaker or partially absent in the COS data
* "d" indicate features that display a different shape or structure
in the COS data
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Sight line identifier
13- 20 F8.5 --- z [0.002/0.5] Redshift
22- 27 A6 --- Line Identified line element
29- 31 I3 --- Ion [1/300] Ion code (G1)
34 A1 --- f_logN [<>an] Flag on logN (G2)
36- 41 F6.3 [cm-2] logN [11/19] Log of the column density
43- 47 F5.3 [cm-2] e_logN [0/1.7] Uncertainty in logN
49- 62 A14 --- r_logN Reference(s) for logN (G3)
65 A1 --- f_b [n~] Flag on b (G2)
67- 71 F5.1 km/s b [0/144] Doppler b-parameter
73- 77 F5.1 km/s e_b [0/42] Uncertainty in b
79- 89 A11 --- r_b ? Reference for b (G3)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode Bibcode
24- 39 A16 --- Aut Author's name(s)
41- 76 A36 --- Comm Comment
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Global notes:
Note (G1): Correlates absorption lines within a sight line in Table 4
with the associated absorber properties in Table 5.
Note (G2): The flags are:
n = normal measurement;
a = feature absent in COS data
< = an upper limit;
> = lower limit;
∼ = an order-of-magnitude estimate when a reliable measurement could not
be obtained.
Note (G3): Identifies the sources or techniques used to construct the
consensus value, with every two-digit portion of the value in the
table corresponding to a source listed in ref.dat file.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Jul-2014