Damped Lyman-alpha Absorbers from Sloan Digital Sky Survey DR16Q with Gaussian processes

Abstract

We present a new catalogue of Damped Lyman-$\alpha$ absorbers from SDSS DR16Q, as well as new estimates of their statistical properties. Our estimates are computed with the Gaussian process models presented in Garnett et al. (2017); Ho et al. (2020) with an improved model for marginalising uncertainty in the mean optical depth of each quasar. We compute the column density distribution function (CDDF) at $2<z<5$, the line density ($\text{d}N/\text{d}X$), and the neutral hydrogen density (${\Omega }_{\text{DLA}}$). Our Gaussian process model provides a posterior probability distribution of the number of DLAs per spectrum, thus allowing unbiased probabilistic predictions of the statistics of DLA populations even with the noisiest data. We measure a non-zero column density distribution function for $N_{\text{HI}}<3\times 10^{22}{\text{cm}}^{-2}$ with $95\%$ confidence limits, and $N_{\text{HI}}\lesssim 10^{22}{\text{cm}}^{-2}$ for spectra with signal-to-noise ratios $>4$. Our results for DLA line density and total hydrogen density are consistent with previous measurements. Despite a small bias due to the poorly measured blue edges of the spectra, we demonstrate that our new model can measure the DLA population statistics when the DLA is in the Lyman-$\beta$ forest region. We verify our results are not sensitive to the signal-to-noise ratios and redshifts of the background quasars although a residual correlation remains for detections from $z_{\text{QSO}}<2.5$, indicating some residual systematics when applying our models on very short spectra, where the SDSS spectral observing window only covers part of the Lyman-$\alpha$ forest.

21 pages, 19 figures, 9 tables. Minor changes to match version published in MNRAS. Codes are available at https://github.com/jibanCat/gp_dla_detection_dr16q_public

References in corpus (15)

• The Sloan Digital Sky Survey Quasar Catalog: Sixteenth Data Release
• On the (Non)Evolution of HI Disks over Cosmic Time
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• The Neutral Hydrogen Cosmological Mass Density at z=5
• An improved measurement of the flux distribution of the Ly-alpha forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
• The Lyman-alpha forest power spectrum from the XQ-100 Legacy Survey
• Reproducing the Kinematics of Damped Lyman-alpha Systems
• The SDSS-DR12 large-scale cross-correlation of Damped Lyman Alpha Systems with the Lyman Alpha Forest
• Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12
• Simulating the effect of high column density absorbers on the one-dimensional Lyman-alpha forest flux power spectrum
• Classification of Broad Absorption Line Quasars with a Convolutional Neural Network
• The effect of dust bias on the census of neutral gas and metals in the high-redshift Universe due to SDSS-II quasar colour selection
• Testing Galaxy Formation Simulations with Damped Lyman-$\alpha$ Abundance and Metallicity Evolution
• Constraining the Halo Mass of Damped Ly$\alpha$ Absorption Systems (DLAs) at $z=2-3.5$ using the Quasar-CMB Lensing Cross-correlation
• Automated Measurement of Quasar Redshift with a Gaussian Process

Cited by in corpus (15)

• DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
• The Dark Energy Spectroscopic Instrument: One-dimensional power spectrum from first Lyman-$\alpha$ forest samples with Fast Fourier Transform
• PRIYA: A New Suite of Lyman-alpha Forest Simulations for Cosmology
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: The Damped Lyman-$\alpha$ systems Catalog
• A Multi-Fidelity Emulator for the Lyman-$\alpha$ Forest Flux Power Spectrum
• The Column Densities of Molecular Gas across Cosmic Time: Bridging Observations and Simulations
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator III: Foreground removal
• Probing the Diffuse Lyman-alpha Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS Survey
• Towards $21$-cm intensity mapping at $z=2.28$ with uGMRT using the tapered gridded estimator II: Cross-polarization power spectrum
• Modeling Post-Reionization HI Distributions in Fuzzy Dark Matter Cosmologies Using Conditional Normalizing Flows
• Probing the parameters of the intergalactic medium using quasars
• The Cosmic Evolution of CIV Absorbers at $1.4<z<4.5$: Insights from $100,000$ Systems in DESI Quasars
• 3D Correlations in the Lyman-$\alpha$ Forest from Early DESI Data
• HI Intensity Mapping cross-correlation with thermal SZ fluctuations: forecasted cosmological parameters estimation for FAST and Planck
• DESI DR1 Lyα 1D power spectrum: The Fast Fourier Transform estimator measurement