The Halo21 Absorption Modeling Challenge: Lessons From "Observing" Synthetic Circumgalactic Absorption Spectra

Abstract

In the Halo21 absorption modeling challenge we generated synthetic absorption spectra of the circumgalactic medium (CGM), and attempted to estimate the metallicity, temperature, and density (Z, T, and nH) of the underlying gas using observational methods. We iteratively generated and analyzed three increasingly-complex data samples: ion column densities of isolated uniform clouds, mock spectra of 1--3 uniform clouds, and mock spectra of high-resolution turbulent mixing zones. We found that the observational estimates were accurate for both uniform cloud samples, with Z, T, and nH retrieved within 0.1 dex of the source value for >90% of absorption systems. In the turbulent-mixing scenario, the mass, temperature, and metallicity of the strongest absorption components were also retrieved with high accuracy. However, the underlying properties of the subdominant components were poorly constrained because the corresponding simulated gas contributed only weakly to the H I absorption profiles. On the other hand, including additional components beyond the dominant ones did improve the fit, consistent with the true existence of complex cloud structures in the source data.

arXiv comment16 pages, 10 figures, submitted. Data and additional figures available upon request

References in corpus (84)

• The chemical composition of the Sun
• The cosmological simulation code GADGET-2
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Cosmological Hydrodynamics with Adaptive Mesh Refinement: a new high resolution code called RAMSES
• Cold streams in early massive hot haloes as the main mode of galaxy formation
• Radiative Transfer in a Clumpy Universe: II. The Utraviolet Extragalactic Background
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• Cosmological simulations of the growth of supermassive black holes and feedback from active galactic nuclei: method and tests
• Galaxies in a simulated $\Lambda$CDM Universe I: cold mode and hot cores
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• On the relation between the Schmidt and Kennicutt-Schmidt star formation laws and its implications for numerical simulations
• Star formation thresholds and galaxy edges: why and where
• Simulating galactic outflows with thermal supernova feedback
• The Cosmic Origins Spectrograph
• Multi-Phase Galaxy Formation: High Velocity Clouds and the Missing Baryon Problem
• The COS-Halos Survey: Rationale, Design, and A Census of Circumgalactic Neutral Hydrogen
• On the Kinematics of the Damped Lyman Alpha Protogalaxies
• The COS-Halos Survey: An Empirical Description of the Metal-Line Absorption in the Low-Redshift Circumgalactic Medium
• Moving mesh cosmology: tracing cosmological gas accretion
• The COS-Halos Survey: Metallicities in the Low-Redshift Circumgalactic Medium
• The impact of angular momentum on black hole accretion rates in simulations of galaxy formation
• A Characteristic Scale for Cold Gas
• A statistical test for Nested Sampling algorithms
• The EAGLE simulations of galaxy formation: the importance of the hydrodynamics scheme
• Cosmological simulations of the circumgalactic medium with 1 kpc resolution: enhanced HI column densities
• Bimodality of low-redshift circumgalactic O VI in non-equilibrium EAGLE zoom simulations
• The Origins of the Circumgalactic Medium in the FIRE Simulations
• Resolving small-scale cold circumgalactic gas in TNG50
• QSO Metal Absorption Systems at High Redshift and the Signature of Hierarchical Galaxy Formation
• The Population of Weak Mg II Absorbers I. A Survey of 26 QSO HIRES/Keck Spectra
• A Mock Data Challenge for the Einstein Gravitational-Wave Telescope
• Constraints on Hydrodynamical Subgrid Models from Quasar Absorption Line Studies of the Simulated Circumgalactic Medium
• The Population of Weak MgII Absorbers. II The Properties of Single-Cloud Systems
• Metal-enriched, sub-kiloparsec gas clumps in the circumgalactic medium of a faint z = 2.5 galaxy
• Modelling the uv/x-ray cosmic background with CUBA
• Simulations of radiative turbulent mixing layers
• Cosmic distribution of highly ionized metals and their physical conditions in the EAGLE simulations
• The impact of local stellar radiation on the HI column density distribution
• Survival and mass growth of cold gas in a turbulent, multiphase medium
• The physical properties of z>2 Lyman limit systems: new constraints for feedback and accretion models
• The Kinematics of Intermediate Redshift Mg II Absorbers
• Instability of Supersonic Cold Streams Feeding Galaxies IV: Survival of Radiatively Cooling Streams
• Low-Redshift Lyman Limit Systems as Diagnostics of Cosmological Inflows and Outflows
• Non-equilibrium chemistry and cooling in the diffuse interstellar medium - II. Shielded gas
• Growth and structure of multiphase gas in the cloud-crushing problem with cooling
• The Fates of the Circumgalactic Medium in the FIRE Simulations
• High Resolution STIS/HST and HIRES/Keck Spectra of Three Weak MgII Absorbers Toward PG 1634+706
• Nature of the Absorbing Gas associated with a Galaxy Group at z~0.4
• On the Spatial and Kinematic Distributions of Mg II Absorbing Gas in <z>=0.7 Galaxies
• On the importance of local sources of radiation for quasar absorption line systems
• A Mock Data and Science Challenge for Detecting an Astrophysical Stochastic Gravitational-Wave Background with Advanced LIGO and Advanced Virgo
• The Cosmic Ultraviolet Baryon Survey (CUBS) -- III. Physical properties and elemental abundances of Lyman limit systems at $z<1$
• The EAGLE simulations of galaxy formation: Public release of particle data
• The COS Absorption Survey of Baryon Harbors: Unveiling the Physical Conditions of Circumgalactic Gas through Multiphase Bayesian Ionization Modeling
• The Absorption Signatures of Dwarf Galaxies: The z=1.04 Multicloud Weak MgII Absorber toward PG 1634+706
• The Multi-phase Absorption Systems Toward PG 1206+459
• The Keck+Magellan Survey for Lyman Limit Absorption II: A Case Study on Metallicity Variations
• A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - IV. Masses and Gas Flows
• The Chemical and Ionization Conditions in Weak Mg II Absorbers
• Cloudy with A Chance of Rain: Accretion Braking of Cold Clouds
• Damped Lyman alpha systems and galaxy formation models - II. High ions and Lyman limit systems
• The Absorption Signature of Six MgII-Selected Systems Over 0.5<z<0.9
• COS-Weak: Probing the CGM using analogs of weak Mg II absorbers at z < 0.3
• A Quadruple-Phase Strong Mg II Absorber at z~0.9902 Toward PG 1634+706
• Models of Five Absorption Line Systems Along the Line of Sight Toward PG0117+213
• Thermal Instability in the CGM of $L_{\star }$ Galaxies: Testing "Precipitation" Models with the FIRE Simulations
• Cloud-by-cloud, multiphase, Bayesian modeling: Application to four weak, low ionization absorbers
• Understanding the strong intervening OVI absorber at z${}_{abs}$ ~0.93 towards PG1206+459
• Thermal Instabilities and Shattering in the High-Redshift WHIM: Convergence Criteria and Implications for Low-Metallicity Strong HI Absorbers
• Observing the circumgalactic medium of simulated galaxies through synthetic absorption spectra
• A Bare Molecular Cloud at z~0.45
• Super-Solar Metallicity in Weak Mg II Absorption Systems at z ~ 1.7
• Probing the physicochemical properties of the Leo Ring and the Leo I group
• Key Physical Processes in the Circumgalactic Medium
• The Second International Pulsar Timing Array Mock Data Challenge
• Probing IGM accretion onto faint Lyα emitters at z~2.8
• Discovery of extremely low-metallicity circumgalactic gas at $z=0.5$ toward Q0454-220
• The z = 0.0777 C III Absorber Towards PHL 1811 as a Case Study of a Low Redshift Weak Metal Line Absorber
• BayesVP: a Bayesian Voigt profile fitting package
• Unified model for quasar absorption line systems
• Examining quasar absorption-line analysis methods: the tension between simulations and observational assumptions key to modelling clouds
• Cool and gusty, with a chance of rain: Dynamics of multiphase CGM around massive galaxies in the Romulus simulations