The HST/ACS+WFC3 Survey for Lyman Limit Systems II: Science

Abstract

We present the first science results from our Hubble Space Telescope Survey for Lyman limit absorption systems (LLS) using the low dispersion spectroscopic modes of the Advanced Camera for Surveys and the Wide Field Camera 3. Through an analysis of 71 quasars, we determine the incidence frequency of LLS per unit redshift and per unit path length, l(z) and l(x) respectively, over the redshift range 1 < z< 2.6, and find a weighted mean of l(x)=0.29 +/-0.05 for 2.0 < z < 2.5 through a joint analysis of our sample and that of Ribaudo et al. (2011). Through stacked spectrum analysis, we determine a median (mean) value of the mean free path to ionizing radiation at z=2.4 of lambda_mfp = 243(252)h^(-1) Mpc, with an error on the mean value of +/- 43h^(-1) Mpc. We also re-evaluate the estimates of lambda_mfp from Prochaska et al. (2009) and place constraints on the evolution of lambda_mfp with redshift, including an estimate of the "breakthrough" redshift of z = 1.6. Consistent with results at higher z, we find that a significant fraction of the opacity for absorption of ionizing photons comes from systems with N_HI <= 10^{17.5} cm^(-2) with a value for the total Lyman opacity of tau_lyman = 0.40 +/- 0.15. Finally, we determine that at minimum, a 5-parameter (4 power-law) model is needed to describe the column density distribution function f(N_HI, X) at z \sim 2.4, find that f(N_HI,X) undergoes no significant change in shape between z \sim 2.4 and z \sim 3.7, and provide our best fit model for f(N_HI,X).

36 pages, 20 figures, 10 tables, revision to match accepted ApJ version

References in corpus (13)

• On the (Non)Evolution of HI Disks over Cosmic Time
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• Cold accretion flows and the nature of high column density HI absorption at redshift 3
• HST-COS Observations of AGN. I. Ultraviolet Composite Spectra of the Ionizing Continuum and Emission Lines
• 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
• Quasars Probing Quasars II: The Anisotropic Clustering of Optically Thick Absorbers around Quasars
• Through Thick and Thin - HI Absorption in Cosmological Simulations
• The Keck+Magellan Survey for Lyman Limit Absorption I: The Frequency Distribution of Super Lyman Limit Systems
• An unbiased measurement of the UV background and its evolution via the proximity effect in quasar spectra
• Neutral hydrogen optical depth near star-forming galaxies at z~2.4 in the Keck Baryonic Structure Survey
• The Evolution of Lyman alpha Absorbers in the Redshift Range 0.5<z<1.9
• Continuous statistics of the Lyman-alpha forest at 0 < z < 1.6: the mean flux, flux distribution, and autocorrelation from HST FOS spectra

Cited by in corpus (69)

• An updated analytic model for the attenuation by the intergalactic medium
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• New Measurements of the Ionizing Ultraviolet Background over 2 < z < 5 and Implications for Hydrogen Reionization
• The AGORA High-Resolution Galaxy Simulations Comparison Project
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• A Cosmic UV/X-ray Background Model Update
• The Origins of the Circumgalactic Medium in the FIRE Simulations
• The Giant Gemini GMOS survey of z>4.4 quasars - I. Measuring the mean free path across cosmic time
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• The Neutral Hydrogen Cosmological Mass Density at z=5
• The ESO UVES Advanced Data Products Quasar Sample - II. Cosmological Evolution of the Neutral Gas Mass Density
• The mean free path of ionizing photons at 5 < z < 6: evidence for rapid evolution near reionization
• New synthesis models of consistent extragalactic background light over cosmic time
• Quasars Probing Quasars VI. Excess HI Absorption Within One Proper Mpc of z~2 Quasars
• Reionization and high-redshift galaxies: the view from quasar absorption lines
• Ultra-faint Ultraviolet Galaxies at z~2 Behind the Lensing Cluster Abell 1689: the Luminosity Function, Dust Extinction and Star Formation Rate Density
• The distribution of neutral hydrogen around high-redshift galaxies and quasars in the EAGLE simulation
• The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift
• The Column Density Distribution and Continuum Opacity of the Intergalactic and Circumgalactic Medium at Redshift <z>=2.4
• The redshift evolution of escape fraction of hydrogen ionizing photons from galaxies
• A Deep Hubble and Keck Search for Definitive Identification of Lyman Continuum Emitters at z~3.1
• The photoheating of the intergalactic medium in synthesis models of the UV background
• The impact of local stellar radiation on the HI column density distribution
• Self-Consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations
• Dissecting the properties of optically-thick hydrogen at the peak of cosmic star formation history
• Peering through the holes: the far UV color of star-forming galaxies at z~3-4 and the escaping fraction of ionizing radiation
• Confronting Simulations of Optically Thick Gas in Massive Halos with Observations at z=2-3
• Probing the Circumgalactic Medium at High-Redshift Using Composite BOSS Spectra of Strong Lyman-alpha Forest Absorbers
• Towards a Unified Description of the Intergalactic Medium at Redshift z~2.5
• The Lyman Continuum Escape Fraction of The Cosmic Horseshoe: A Test of Indirect Estimates
• The COS CGM Compendium. III: Metallicity and Physical Properties of the Cool Circumgalactic Medium at z<1
• The Keck+Magellan Survey for Lyman Limit Absorption III: Sample Definition and Column Density Measurements
• Cosmic Reionization After Planck and Before JWST: An Analytic Approach
• MUSE Analysis of Gas around Galaxies (MAGG) -- IV: The gaseous environment of $z\sim$ 3-4 Lyman-alpha emitting galaxies
• Lyman-Alpha Emitting Galaxies as a Probe of Reionization: Large-Scale Bubble Morphology and Small-Scale Absorbers
• Spectral shapes of the Lyman-alpha emission from galaxies: I. blueshifted emission and intrinsic invariance with redshift
• The Impact of Different Physical Processes on the Statistics of Lyman-limit and Damped Lyman-alpha Absorbers
• Probing the metallicity and ionization state of the circumgalactic medium at z~6 and beyond with OI absorption
• The High-Ion Content and Kinematics of Low-Redshift Lyman Limit Systems
• Precious Metals in SDSS Quasar Spectra II: Tracking the Evolution of Strong, 0.4 < z < 2.3 MgII Absorbers with Thousands of Systems
• The Lyman continuum escape fraction and the Mean Free Path of hydrogen ionizing photons for bright z~4 QSOs from SDSS DR14
• Urchin: A Reverse Ray Tracer for Astrophysical Applications
• The Effect of Fluctuations on the Helium-Ionizing Background
• The case against large intensity fluctuations in the z ~ 2.5 HeII Lyman-alpha forest
• Lyman Continuum Escape Fraction from Low-mass Starbursts at z=1.3
• The mean free path of hydrogen ionizing photons during the epoch of reionization
• CosmoReionMC: A package for estimating cosmological and astrophysical parameters using CMB, Lyman-α absorption and global 21 cm data
• The spectral and environment properties of $z\sim 2.0-2.5$ quasar pairs
• An Ultraviolet Survey of Low-Redshift Partial Lyman-Limit Systems with the HST Cosmic Origins Spectrograph
• The evolution of the low-density HI intergalactic medium from z=3.6 to 0: Data, transmitted flux and HI column density
• Imprints of the first billion years: Lyman limit systems at $z\sim 5$
• UV Background Fluctuations and Three-Point Correlations in the Large Scale Clustering of the Lyman-alpha Forest
• The HI Column Density Distribution of the Galactic Disk and Halo
• The Flatness and Sudden Evolution of the Intergalactic Ionizing Background
• The impact of temperature fluctuations on the large-scale clustering of the Ly$\alpha$ forest
• A ~6 Mpc overdensity at z = 2.7 detected along a pair of quasar sight lines: filament or protocluster?
• Semi-numeric simulations of helium reionization and the fluctuating radiation background
• Flux sensitivity requirements for the detection of Lyman continuum radiation drop-ins from star-forming galaxies below redshifts of 3
• Forecasting constraints on the mean free path of ionizing photons at $z\ge 5.4$ from the Lyman-$\alpha$ forest flux auto-correlation function
• Detecting neutral hydrogen at z > 3 in large spectroscopic surveys of quasars
• Distinguishing Between Photoionized and Collisionally Ionized Gas in the Circumgalactic Medium
• Investigating the Physics and Environment of Lyman Limit Systems in Cosmological Simulations
• Exploring Damped Lyman-$\alpha$ System Host Galaxies using Gamma-ray Bursts
• The Lyman-limit photon mean free path at the end of late reionisation in the Sherwood-Relics simulations
• A Global Census of Metals in the Universe
• On the Metallicities and Kinematics of the Circumgalactic Media of Damped Ly$\alpha$ Systems at $z\sim 2.5$
• Constraint on Matter Power Spectrum on $10^6-10^9{M}_{\odot }$ Scales from ${\tau }_e$
• Discovery of three new near-pristine absorption clouds at $z=2.6$-4.4
• FEASTS and MHONGOOSE: HI Column Density Distribution at $z=0$ for $N_{\mathrm{HI}}>10^{17.8}{\mathrm{cm}}^{-2}$