J/ApJS/258/18 Damped Lyα systems from SDSS DR16Q (Chabanier+, 2022)
The completed Sloan Digital Sky Survey IV extended Baryon Oscillation
Spectroscopic Survey: the damped Lyα systems catalog.
Chabanier S., Etourneau T., Le Goff J.-M., Rich J., Stermer J.,
Abolfathi B., Font-Ribera A., Gonzalez-Morales A.X., de la Macorra A.,
Perez-Rafols I., Petitjean P., Pieri M.M., Ravoux C., Rossi G.,
Schneider D.P.
<Astrophys. J. Suppl. Ser., 258, 18 (2022)>
=2022ApJS..258...18C 2022ApJS..258...18C
ADC_Keywords: Intergalactic medium; QSOs; Spectra, optical; Redshifts
Keywords: Intergalactic medium ; Quasar absorption line spectroscopy ;
Catalogs
Abstract:
We present the characteristics of the damped Lyα (DLA) systems
found in data release DR16 of the extended Baryon Oscillation
Spectroscopic Survey of the Sloan Digital Sky Survey. The DLAs were
identified using the convolutional neural network of
Parks et al. (2018MNRAS.476.1151P 2018MNRAS.476.1151P). A total of 117458 absorber
candidates were found with 2≤zDLA≤5.5 and
19.7≤log(N(HI)/cm-2)≤22, including 57136 DLA candidates with
log(N(HI)/cm-2)≥20.3. Mock quasar spectra were used to estimate
the DLA detection efficiency and the purity of the resulting catalog.
Restricting the quasar sample to bright forests, i.e., those with mean
forest fluxes fλ>2x10-19W/m2/nm, the efficiency and
purity are greater than 90% for DLAs with column densities in the
range 20.1≤log(N(HI)/cm-2)≤22.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
dr16dla.dat 116 117458 The DR16 damped Lyα (DLA) catalog
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See also:
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/ApJ/635/123 : The SDSS-DR3 damped Lyα survey (Prochaska+, 2005)
J/A+A/505/1087 : DLAs in SDSS-DR7 (Noterdaeme+, 2009)
J/A+A/547/L1 : SDSS-III DR9 DLA catalogue (Noterdaeme+, 2012)
J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)
J/ApJ/775/78 : Lyman limit abs. systems in z∼3 QSOs (Fumagalli+, 2013)
J/A+A/559/A85 : 1D Lya forest power spectrum (Palanque-Delabrouille+, 2013)
J/MNRAS/472/1850 : Detecting damped Lyα absorbers (Garnett+, 2017)
Byte-by-byte Description of file: dr16dla.dat
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Bytes Format Units Label Explanations
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1- 10 I10 --- ID [7095815/554679218]?=-1 The SDSS
identifier as found in DR16Q, Cat. VII/289
(THING_ID)
12- 21 F10.8 --- zQSO [2/5.6] Quasar redshift of the sight
line using the Z_PCA estimator of DR16Q
(Z_QSO) (1)
23- 32 F10.8 --- zCNN [2/5.4] Absorber redshift as found by
the convolutional neural networks (CNN;
Parks+ 2018MNRAS.476.1151P 2018MNRAS.476.1151P) (Z_CNN)
34- 39 F6.4 --- Conf [0.1/1] Confidence parameter of the CNN
(>0.5=highly confident absorbers)
(CONF_CNN)
41- 49 F9.6 [cm-2] NHIcnn [19.7/22.3] Logarithm of the absorber
column density as found by the CNN
(NHI_CNN)
51- 58 F8.3 10-19W/m2/nm Flux [-0.99/73.6]?=- Mean forest flux in
10-19W/m2/nm units (MEAN_FLUX) (2)
60- 65 F6.3 --- SNR [-1.3/41] Mean signal-to-noise ratio of
the sight line
67- 71 I5 --- Plate [269/11704] SDSS spectroscopic plate of
the sight line as found in DR16Q
73- 77 I5 d MJD [51612/58543] SDSS modified Julian date
of observation of the sight line as
found in DR16Q
79- 82 I4 --- Fiber [1/1000] SDSS spectroscopic fiber
identification of the sight line as
found in DR16Q (FIBERID)
84- 94 F11.7 deg RAdeg Right ascension (J2000) of the sight
line as found in DR16Q (RA)
96- 106 F11.7 deg DEdeg [-17.6/70] Declination (J2000) of the
sight line as found in DR16Q (DEC)
108- 116 F9.6 [cm-2] NHIfit [19.29/22.4]?=-1 Logarithm of the
absorber column density as found by the
Voigt profile fitter for absorbers in
the rest-frame range
1040Å≤λRF<1216Å (NHI_FIT)
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Note (1): We use the quasar redshift estimator, Z_PCA, generated by principal
component analysis (PCA), using the redvsblue algorithm
(http://github.com/londumas/redvsblue).
Note (2): The efficiency and purity of sight lines with Flux>2x10-19W/m2/nm
are greater than 90% for absorbers with 20.1≤log(N(HI)/cm-2)≤22.
-1 = absorbers that do not meet the criteria or
if the fitter could not converge on one value.
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History:
FITS file downloaded from:
http://drive.google.com/drive/folders/1UaFHVwSNPpqkxTbcbR8mVRJ5BUR9KHzA
(End) Emmanuelle Perret [CDS] 29-Apr-2022