Abstract
We present a measurement of baryonic acoustic oscillations (BAOs) from Ly
α
absorption and quasars at an effective redshift
using the complete extended Baryonic Oscillation Spectroscopic ...Survey (eBOSS). The 16th and final eBOSS data release (SDSS DR16) contains all data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic Survey (BOSS), providing 210,005 quasars with
z
q
> 2.10 that are used to measure Ly
α
absorption. We measure the BAO scale both in the autocorrelation of Ly
α
absorption and in its cross-correlation with 341,468 quasars with redshift
z
q
> 1.77. Apart from the statistical gain from new quasars and deeper observations, the main improvements over previous work come from more accurate modeling of physical and instrumental correlations and the use of new sets of mock data. Combining the BAO measurement from the auto- and cross-correlation yields the constraints of the two ratios
and
, where the error bars are statistical. These results are within 1.5
σ
of the prediction of the flat-ΛCDM cosmology of Planck (2016). The analysis code,
picca
, the catalog of the flux transmission field measurements, and the Δ
χ
2
surfaces are publicly available.
Abstract
We present the characteristics of the damped Ly
α
(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. (2018). A total of 117,458 absorber candidates were found with 2 ≤
z
DLA
≤ 5.5 and
19.7
≤
log
(
N
(
H
I
)
/
cm
−
2
)
≤
22
, including 57,136 DLA candidates with
log
(
N
(
H
I
)
/
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
f
λ
¯
>
2
×
10
−
19
W
m
−
2
nm
−
1
, the efficiency and purity are greater than 90% for DLAs with column densities in the range
20.1
≤
log
(
N
(
H
I
)
/
cm
−
2
)
≤
22
.
We present the characteristics of the Damped Lyman-$\alpha$ (DLA) systems
found in the data release DR16 of the extended Baryon Oscillation Spectroscopic
Survey (eBOSS) of the Sloan Digital Sky ...Survey (SDSS). DLAs were identified
using the convolutional neural network (CNN) of~\cite{Parks2018}. A total of
117,458 absorber candidates were found with $2 \leq \zdla \leq 5.5$ and $19.7
\leq \lognhi \leq 22$, including 57,136 DLA candidates with $\lognhi \geq
20.3$. Mock quasar spectra were used to estimate DLA detection efficiency and
the purity of the resulting catalog. Restricting the quasar sample to bright
forests, i.e. those with mean forest fluxes $\meanflux>2\times\fluxunit$, the
completeness and purity are greater than 90\% for DLAs with column densities in
the range $20.1\leq \lognhi \leq 22$.
2020 ApJ 901 2 153 We present a measurement of baryonic acoustic oscillations (BAO) from
Lyman-$\alpha$ (Ly$\alpha$) absorption and quasars at an effective redshift
$z=2.33$ using the complete ...extended Baryonic Oscillation Spectroscopic Survey
(eBOSS). The sixteenth and final eBOSS data release (SDSS DR16) contains all
data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic
Survey (BOSS), providing $210,005$ quasars with $z_{q}>2.10$ that are used to
measure Ly$\alpha$ absorption. We measure the BAO scale both in the
auto-correlation of Ly$\alpha$ absorption and in its cross correlation with
$341,468$ quasars with redshift $z_{q}>1.77$. Apart from the statistical gain
from new quasars and deeper observations, the main improvements over previous
work come from more accurate modeling of physical and instrumental correlations
and the use of new sets of mock data. Combining the BAO measurement from the
auto- and cross-correlation yields the constraints of the two ratios
$D_{H}(z=2.33)/r_{d} = 8.99 \pm 0.19$ and $D_{M}(z=2.33)/r_{d} = 37.5 \pm 1.1$,
where the error bars are statistical. These results are within $1.5\sigma$ of
the prediction of the flat-$\Lambda$CDM cosmology of Planck~(2016). The
analysis code, \texttt{picca}, the catalog of the flux-transmission field
measurements, and the $\Delta \chi^{2}$ surfaces are publicly available.
We present the characteristics of the Damped Lyman-\(\alpha\) (DLA) systems found in the data release DR16 of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky ...Survey (SDSS). DLAs were identified using the convolutional neural network (CNN) of~\cite{Parks2018}. A total of 117,458 absorber candidates were found with \(2 \leq \zdla \leq 5.5\) and \(19.7 \leq \lognhi \leq 22\), including 57,136 DLA candidates with \(\lognhi \geq 20.3\). Mock quasar spectra were used to estimate DLA detection efficiency and the purity of the resulting catalog. Restricting the quasar sample to bright forests, i.e. those with mean forest fluxes \(\meanflux>2\times\fluxunit\), the completeness and purity are greater than 90\% for DLAs with column densities in the range \(20.1\leq \lognhi \leq 22\).
We present a measurement of baryonic acoustic oscillations (BAO) from Lyman-\(\alpha\) (Ly\(\alpha\)) absorption and quasars at an effective redshift \(z=2.33\) using the complete extended Baryonic ...Oscillation Spectroscopic Survey (eBOSS). The sixteenth and final eBOSS data release (SDSS DR16) contains all data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic Survey (BOSS), providing \(210,005\) quasars with \(z_{q}>2.10\) that are used to measure Ly\(\alpha\) absorption. We measure the BAO scale both in the auto-correlation of Ly\(\alpha\) absorption and in its cross correlation with \(341,468\) quasars with redshift \(z_{q}>1.77\). Apart from the statistical gain from new quasars and deeper observations, the main improvements over previous work come from more accurate modeling of physical and instrumental correlations and the use of new sets of mock data. Combining the BAO measurement from the auto- and cross-correlation yields the constraints of the two ratios \(D_{H}(z=2.33)/r_{d} = 8.99 \pm 0.19\) and \(D_{M}(z=2.33)/r_{d} = 37.5 \pm 1.1\), where the error bars are statistical. These results are within \(1.5\sigma\) of the prediction of the flat-\(\Lambda\)CDM cosmology of Planck~(2016). The analysis code, \texttt{picca}, the catalog of the flux-transmission field measurements, and the \(\Delta \chi^{2}\) surfaces are publicly available.
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