A framework to measure the properties of intergalactic metal systems with two-point flux statistics

Abstract

The abundance, temperature, and clustering of metals in the intergalactic medium are important parameters for understanding their cosmic evolution and quantifying their impact on cosmological analysis with the Ly $\alpha$ forest. The properties of these systems are typically measured from individual quasar spectra redward of the quasar's Ly $\alpha$ emission line, yet that approach may provide biased results due to selection effects. We present an alternative approach to measure these properties in an unbiased manner with the two-point statistics commonly employed to quantify large-scale structure. Our model treats the observed flux of a large sample of quasar spectra as a continuous field and describes the one-dimensional, two-point statistics of this field with three parameters per ion: the abundance (column density distribution), temperature (Doppler parameter) and clustering (cloud-cloud correlation function). We demonstrate this approach on multiple ions (e.g., C IV, Si IV, Mg II) with early data from the Dark Energy Spectroscopic Instrument (DESI) and high-resolution spectra from the literature. Our initial results show some evidence that the C IV abundance is higher than previous measurements and evidence for abundance evolution over time. The first full year of DESI observations will have over an order of magnitude more quasar spectra than this study. In a future paper we will use those data to measure the growth of clustering and its impact on the Ly $\alpha$ forest, as well as test other DESI analysis infrastructure such as the pipeline noise estimates and the resolution matrix.

arXiv comment15 pages, 14 figures, accepted to MNRAS

References in corpus (56)

• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Sloan Digital Sky Survey: Technical Summary
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Seventh Data Release of the Sloan Digital Sky Survey
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Halo Models of Large Scale Structure
• Overview of the DESI Legacy Imaging Surveys
• The Circumgalactic Medium
• The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
• The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey
• Measurement of BAO correlations at $z=2.3$ with SDSS DR12 \lya-Forests
• Metallicity of the intergalactic medium using pixel statistics. II. The distribution of metals as traced by C IV
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon acoustic oscillations with Lyman-$\alpha$ forests
• The Evolution of the Intergalactic Medium
• The Minimum Universal Metal Density Between Redshifts of 1.5 and 5.5
• The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument
• The one-dimensional Ly-alpha forest power spectrum from BOSS
• The Enrichment History of the Intergalactic Medium: Measuring the CIV/HI Ratio in the Lyman Alpha Forest
• Target Selection and Validation of DESI Quasars
• The Robotic Multi-Object Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI)
• The one-dimensional power spectrum from the SDSS DR14 Ly$\alpha$ forests
• Nested sampling for physical scientists
• Voigt Profile Fitting to Quasar Absorption Lines: An Analytic Approximation to the Voigt-Hjerting Function
• Galactic and Circumgalactic OVI and its Impact on the Cosmological Metal and Baryon Budgets at 2<z<3.5
• Extended Hot Halos Around Isolated Galaxies Observed in the ROSAT All-Sky Survey
• Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT
• The Sources of Intergalactic Metals
• The UVES Spectral Quasar Absorption Database (SQUAD) Data Release 1: The first 10 million seconds
• The First Data Release of the KODIAQ Survey
• The Last Eight-Billion Years of Intergalactic CIV Evolution
• The rise of the C IV mass density at z<2.5
• Probing the Circumgalactic Medium at High-Redshift Using Composite BOSS Spectra of Strong Lyman-alpha Forest Absorbers
• Precious Metals in SDSS Quasar Spectra I: Tracking the Evolution of Strong, 1.5 < z < 4.5 CIV Absorbers with Thousands of Systems
• The Second Data Release of the KODIAQ Survey
• Preliminary Target Selection for the DESI Quasar (QSO) Sample
• Metallicity of the Intergalactic Medium Using Pixel Statistics: I. Method
• The Carbon Content of Intergalactic Gas at z=4.25 and its Evolution Toward z=2.4
• Properties of QSO Metal Line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies
• Spectro-Perfectionism: An Algorithmic Framework for Photon Noise-Limited Extraction of Optical Fiber Spectroscopy
• Optimal 1D Ly$\alpha$ Forest Power Spectrum Estimation -- II. KODIAQ, SQUAD & XQ-100
• Classification of Broad Absorption Line Quasars with a Convolutional Neural Network
• Pixel correlation searches for OVI in the Lyman alpha forest and the volume filling factor of metals in the Intergalactic Medium at z ~ 2-3.5
• The Composite Spectrum of Strong Lyman-alpha Forest Absorbers
• The Clustering of Intergalactic Metals
• Optimal 1D Ly-$\alpha$ Forest Power Spectrum Estimation I: DESI-Lite Spectra
• The extended Baryon Oscillation Spectroscopic Survey: measuring the cross-correlation between the MgII flux transmission field and quasars and galaxies at $z=0.59$
• Evolution of CIV Absorbers I. The Cosmic Incidence
• A Search for Oxygen in the Low-Density Lyman-alpha Forest Using the Sloan Digital Sky Survey
• Absorber Model: the Halo-like model for the Lyman-alpha forest
• Probing Reionization and Early Cosmic Enrichment with the MgII Forest
• Agnostic Stacking of Intergalactic Doublet Absorption: Measuring the NeVIII Population
• The impact and mitigation of broad absorption line quasars in Lyman$-\alpha$ forest correlations
• Constraining IGM enrichment and metallicity with the C IV forest correlation function
• Metal Lines Associated with the Lyman-alpha Forest from eBOSS Data

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• Unveiling Dark Matter free-streaming at the smallest scales with high redshift Lyman-alpha forest
• The Dark Energy Spectroscopic Instrument: One-dimensional power spectrum from first Lyman-$\alpha$ forest samples with Fast Fourier Transform
• Detecting the IGM metal enrichment with the 2-point correlation function of the flux. Application to the UVES deep spectrum