J/ApJ/866/33 The COS CGM compendium. I. Initial results (Lehner+, 2018)
The COS CGM compendium.
I. Survey design and initial results.
Lehner N., Wotta C.B., Howk J.C., O'Meara J.M., Oppenheimer B.D.,
Cooksey K.L.
<Astrophys. J., 866, 33 (2018)>
=2018ApJ...866...33L 2018ApJ...866...33L
ADC_Keywords: H I data; Active gal. nuclei; QSOs; Spectra, ultraviolet;
Redshifts; Abundances
Keywords: galaxies: abundances ; galaxies: halos ; quasars: absorption lines
Abstract:
We present a neutral hydrogen-selected absorption-line survey of gas
with HI column densities 15<logNHI<19 at z≲1 using the Cosmic
Origins Spectrograph on the Hubble Space Telescope. Our main aim is to
determine the metallicity distribution of these absorbers. Our sample
consists of 224 absorbers selected on the basis of their HI absorption
strength. Here we discuss the properties of our survey and the
immediate empirical results. We find singly and doubly ionized metal
species, and HI typically have similar velocity profiles, implying
they probe gas in the same or similar environments. The ionic ratios
(e.g., NCII/NCIII, NOI/NCII) indicate that the gas in these
absorbers is largely ionized, and the ionization conditions are quite
comparable across the sampled NHI range. The Doppler parameters of
the HI imply T≲5x104K on average, consistent with the gas being
photoionized. The MgII column densities span >2 orders of magnitude at
any given NHI, indicating a wide range of metallicities (from solar
to <1/100 solar). In the range of 16.2≲logNHI≲17, there is a gap
in the NMgII distribution corresponding to gas with ∼10% solar
metallicity, consistent with the gap seen in the previously identified
bimodal metallicity distribution in this column density regime. Less
than 3% of the absorbers in our sample show no detectable metal
absorption, implying that truly pristine gas at z≲1 is uncommon. We
find <[FeII/MgII]≥-0.4±0.3, and since α-enhancement can
affect this ratio, dust depletion is extremely mild.
Description:
Our survey makes use of the extended archival UV spectroscopy of AGN
and QSOs taken with the highest-resolution modes of the HST-Cosmic
Origins Spectrograph (COS) instrument.
We used only data taken with the COS G130M and G160M gratings, with
spectral resolutions R∼17000 (or about 15-20km/s). All the COS G130M
and G160M data were retrieved from MAST.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 336 Sample of targets
table2.dat 31 85 Atomic parameters and abundances
for the surveyed atoms and ions
table3.dat 87 4271 Average velocities and column densities
of the metal ions in the weak HI absorbers
table4.dat 87 570 Average velocities and column densities
of the metal ions
from the L13 (Lehner+, 2013, J/ApJ/770/138) sample
table9.dat 119 3306 Results
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
J/A+AS/108/287 : Atomic data (Verner+, 1994)
J/ApJS/136/463 : Distances and metallicities of HVCs and IVCs (Wakker, 2001)
J/ApJ/651/61 : Optically thick absorbers near luminous QSOs (Hennawi+, 2006)
J/ApJ/676/262 : PKS1302-102 intergalactic absorption system (Cooksey+, 2008)
J/ApJ/700/1299 : Gas-phase element depletions in the ISM (Jenkins, 2009)
J/ApJS/193/28 : Galaxy survey around 20 UV-bright quasars (Prochaska+, 2011)
J/ApJ/740/91 : Lyα & OVI in galaxies around quasars (Prochaska+, 2011)
J/ApJ/755/89 : Metallicities of damped Lyα systems (Rafelski+, 2012)
J/ApJ/770/138 : Metallicities of Lyman limit systems and DLA (Lehner+, 2013)
J/ApJ/776/136 : QPQ VI. HI absorption of z∼2 quasars (Prochaska+, 2013)
J/ApJ/788/119 : Highly ionized gas properties of quasars (Lehner+, 2014)
J/ApJ/794/156 : MgII/FeII absorption profile for 0.3<z<1.4 gal. (Rubin+, 2014)
J/ApJ/794/75 : HST-COS UV spectra observations of AGNs (Stevans+, 2014)
J/MNRAS/437/2017 : HI-galaxy cross-correlation at z≲1 (Tejos+, 2014)
J/ApJ/804/79 : HST/COS obs. of QSOs within 600kpc of M31 (Lehner+, 2015)
J/AJ/150/111 : KODIAQ DR1 (O'Meara+, 2015)
J/ApJ/814/40 : Nearby galaxy filaments with UV obs. (Wakker+, 2015)
J/ApJ/817/111 : HST/COS survey of z<0.9 AGNs. I. (Danforth+, 2016)
J/ApJ/833/270 : HI-selected-Lyman limit system metallicities (Glidden+, 2016)
J/ApJ/833/283 : HI-selected Lyman limit systems metallicities (Lehner+, 2016)
J/MNRAS/458/4074 : UVES Advanced Data Products QSO Sample. VI. (Quiret+, 2016)
J/ApJS/230/6 : HST -COS & -STIS abs. spectroscopy. II. (Keeney+, 2017)
J/AJ/154/114 : KODIAQ DR2 (O'Meara+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Identifier (JHHMMSS.ss+DDMMSS.s)
21- 44 A24 --- HST Name used in HST observation (1)
46- 52 F7.5 --- z [0.17/1.5] Spectroscopic redshift from emission lines
54- 59 F6.1 0.1nm Min [1066/1431] Minimum wavelength of spectral coverage;
in Angstrom units
61- 66 F6.1 0.1nm Max [1367/1802] Maximum wavelength of spectral coverage;
in Angstrom units
68- 72 F5.1 --- SNR [1/105.7] Signal-to-Noise (2)
74- 84 A11 --- PID HST observation number identifier(s)
86- 91 A6 --- Nabs Number of absorbers (3)
93- 97 A5 --- Inst Ground observation instrument (4)
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Note (1): Each targets was observed with COS G130M and/or G160M.
Note (2): For COS spectra binned by 3 pixels per resolution element.
Note (3): Along a given sightline where we could estimate reliable column
densities and metallicities. If a number is between parentheses in
the column Nabs, it means we could only derive a lower limit on
N(HI), except for J131956.23+272808.2 where the absorber at
z=0.660356 was originally selected based on the presence of
MgII (see text for more details); in all these cases, these
absorbers are not included further in our HI-selected survey.
Note (4): Instrument as follows:
HIRES = Keck I High Resolution Echelle Spectrometer.
UVES = VLT Ultraviolet and Visual Echelle Spectrograph.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Sp Species identifier sorted in decreasing order
of abundances
9- 17 F9.4 0.1nm lambda [608.3/2803.6] Wavelength; Angstroms
19- 23 F5.2 [-] log(lf) [-0.7/3.3] log wavelength * oscillator strength
(logλf)
25- 29 F5.2 [Sun] A [7.14/12.0] Solar abundance
from Asplund+ (2009ARA&A..47..481A 2009ARA&A..47..481A)
31 I1 --- Flag [1/5] Ionization flag (1)
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Note (1): Ionization flag as follows:
1 = these are α-elements with low ionization stages that are always
used if uncontaminated;
2 = always used if uncontaminated but allowing for possible variation in
the [C/α] ratio;
3 = often used, but sometimes removed because nucleosythesis or depletion
can affect the N/α or Fe/α ratio, respectively;
4 = sometimes used depending on the ionization conditions as these ions
can be produced by multiple ionization processes;
5 = never included because their ionization stages are too high to
typically be produced by the same processes or at the same densities
than observed for lower ions and H I.
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Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Identifier (JHHMMSS.ss+DDMMSS.s)
21- 28 F8.6 --- z [0.09/0.9] Spectroscopic redshift of the absorber
30- 48 A19 --- Line Species and wavelength (Angstroms) of line (1)
51- 54 I4 km/s v1 [-312/-3]? Lower rest frame velocity (2)
56- 58 I3 km/s v2 [1/270]? Upper rest frame velocity (2)
60- 64 F5.1 km/s Vel [-44/62.3]? Average velocity
66- 69 F4.1 km/s e_Vel [0.1/79]? Uncertainty in Vel
71 A1 --- l_logN Limit flag on logN (3)
73- 77 F5.2 [cm-2] logN [10.8/19]? Log column density of line
79- 82 F4.2 [cm-2] E_logN [0.01/0.5]? Upper uncertainty in logN
84- 87 F4.2 [cm-2] e_logN [0.01/0.7]? Lower uncertainty in logN
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Note (1): For a given atom or ion with more than one transition, we list in
the row with no wavelength information the adopted weighted average
column densities and velocities.
Note (2): Of the integration of the absorption profile.
Note (3): Upper limits (<) are non-detections quoted at the 2σ level.
Column densities preceded by > are lower limits owing to saturation
in the absorption (lower limit values were increased by 0.15dex
to additionally correct for saturation, see text for more detail).
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Identifier (JHHMMSS.ss+DDMMSS.s)
21- 44 A24 --- HST Name used in HST observation
46- 53 F8.6 --- z [0.09/0.9] Spectroscopic redshift of the absorber
55- 62 F8.6 --- e_z [1e-5/0.0008] Uncertainty in z
64- 69 A6 --- Sp Species identifier
71- 76 F6.1 km/s v1 [-312/999] Minimum integration range velocity (1)
78- 82 F5.1 km/s v2 [1/999] Maximum integration range velocity (1)
84- 88 F5.1 km/s Vel [-66.7/999] Average velocity (1)
90- 94 F5.1 km/s e_Vel [0.2/999] Uncertainty in Vel (1)
96-100 F5.2 [cm-2] logN [10.8/19] log column density
102-105 F4.2 [cm-2] E_logN [0.01/0.3] Upper uncertainty on logN
107-110 F4.2 [cm-2] e_logN [0.01/0.7] Lower uncertainty on logN
112-113 I2 --- Det [-2/0]? Detection flag (2)
115 I1 --- Rel [1/3] Reliability flag (3)
117-119 I3 --- Uniq [1/224] Unique identification number of absorber
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Note (1): A 999.0 corresponds to no absorption observed at the 2σ level.
Note (2): Detection flag as follows:
0 = detection;
-1 = upper limit;
-2 = lower limit.
Note (3): Depending if a single or several transitions were detected, a
reliability weighting is assigned as follows:
1 = most reliable: results based on several transitions or a non-detection
(a non-detection is always reliable since it would be estimated in
an uncontaminated region of the spectrum;
2 = reliable: results based on at least two transitions, but were only one
transition is detected at the 2σ level and the upper limits
agree with that detection;
3 = less reliable: results based only on a single transition or
several saturated transitions.
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History:
From electronic version of the journal
References:
Lehner et al. Paper I. 2018ApJ...866...33L 2018ApJ...866...33L This catalog
Wotta et al. Paper II. 2019ApJ...872...81W 2019ApJ...872...81W Cat. J/ApJ/872/81
Lehner et al. Paper III. 2019ApJ...887....5L 2019ApJ...887....5L
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Oct-2019