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Quasars Probing Quasars VIII. The Physical Properties of the Cool Circumgalactic Medium Surrounding z ~ 2-3 Massive Galaxies Hosting Quasars

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Paper breakdownThe authors' claims, conditions and measurements, as JSON Signed receiptProof this review has not been altered
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Marie Wingyee Lau (1), J. Xavier Prochaska (1), Joseph F. Hennawi (2) ((1) UCO/Lick Observatory, UC Santa Cruz, (2) Max Planck Institute for Astronomy)

Astrophysics of Galaxies · Submitted 20 Oct 2015

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim Taken together these anomalies suggest that transverse sightlines are at least in some cases possibly illuminated.

how it is stated · hedged possibility 1.00 read the record →

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arXiv ID1510.06018 (version 3)
Pith IDILGBLLOP, Pith's permanent record of this paper and its review
Citation(2) Max Planck Institute for Astronomy), Joseph F. Hennawi (2) ((1) UCO/Lick Observatory, J. Xavier Prochaska (1), Marie Wingyee Lau (1), UC Santa Cruz. "Quasars Probing Quasars VIII. The Physical Properties of the Cool Circumgalactic Medium Surrounding z ~ 2-3 Massive Galaxies Hosting Quasars." arXiv:1510.06018 (2015). https://pith.science/paper/ILGBLLOP
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The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

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Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-09-23: 1 request, 7,732 input tokens.

What the abstract itself states, as probabilities: claims first 0.06 · states limitation 0.67 · human participants 0.01 · controlled comparison 0.41 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.91 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v3. Results and the main claim are underlined; .

We characterize the physical properties of the cool T ~10^4 K circumgalactic medium surrounding z ~2-3 quasar host galaxies, which are predicted to evolve into present day massive ellipticals. Using a statistical sample of 14 quasar pairs with projected separation < 300 kpc and high dispersion, high S/N spectra, we find extreme kinematics with low metal ion lines typically spanning ~ 500 km/s, exceeding any previously studied galactic population. The CGM is significantly enriched, even beyond the virial radius, with a median metallicity [M/H] ~ -0.6. The alpha/Fe abundance ratio is enhanced, suggesting that halo gas is primarily enriched by core-collapse supernovae. The projected cool gas mass within the virial radius is estimated to be 1.9*10^11 M_sun (R_\perp/160 kpc)^2, accounting for ~ 1/3 of the galaxy halo baryonic budget. The ionization state of CGM gas increases with projected distance from the foreground quasars, contrary to expectation if the quasar dominates the ionizing radiation flux. However, we also found peculiarities not exhibited in the CGM of other galaxy populations. In one absorption system, we may be detecting unresolved fluorescent Ly-alpha emission, and another system shows strong NV lines. Taken together these anomalies suggest that transverse sightlines are at least in some cases possibly illuminated. We also discovered a peculiar case where detection of the CII* fine structure line implies an electron density > 100 cm^-3 and subparsec scale gas clumps.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We characterize the physical properties of the cool T ~10^4 K circumgalactic medium surrounding z ~2-3 quasar host galaxies, which are predicted to evolve into present day massive ellipticals. contribution 0.89 0.56 0.10 asserted 0.87
s1 Using a statistical sample of 14 quasar pairs with projected separation < 300 kpc and high dispersion, high S/N spectra, we find extreme kinematics with low metal ion lines typically spanning ~ 500 km/s, exceeding any previously studied galactic population. result 0.83 0.97 0.15 asserted 1.00
s2 The CGM is significantly enriched, even beyond the virial radius, with a median metallicity [M/H] ~ -0.6. result 1.00 0.93 0.17 asserted 1.00
s3 The alpha/Fe abundance ratio is enhanced, suggesting that halo gas is primarily enriched by core-collapse supernovae. interpretation 0.81 0.87 0.08 hedged possibility 0.99
s4 The projected cool gas mass within the virial radius is estimated to be 1.9*10^11 M_sun (R_\perp/160 kpc)^2, accounting for ~ 1/3 of the galaxy halo baryonic budget. result 1.00 0.92 0.17 asserted 0.97
s5 The ionization state of CGM gas increases with projected distance from the foreground quasars, contrary to expectation if the quasar dominates the ionizing radiation flux. result 0.98 0.91 0.12 asserted 1.00
s6 However, we also found peculiarities not exhibited in the CGM of other galaxy populations. result 0.94 0.81 0.04 asserted 1.00
s7 In one absorption system, we may be detecting unresolved fluorescent Ly-alpha emission, and another system shows strong NV lines. result 1.00 0.95 0.03 hedged possibility 0.83
s8 Taken together these anomalies suggest that transverse sightlines are at least in some cases possibly illuminated. interpretation 1.00 0.81 0.14 hedged possibility 1.00
s9 We also discovered a peculiar case where detection of the CII* fine structure line implies an electron density > 100 cm^-3 and subparsec scale gas clumps. result 1.00 0.97 0.05 asserted 0.85

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 0.80.

What was examined, and what was not

sources read
  • arXiv listing abstract v3
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper
Original abstract

We characterize the physical properties of the cool T ~10^4 K circumgalactic medium surrounding z ~2-3 quasar host galaxies, which are predicted to evolve into present day massive ellipticals. Using a statistical sample of 14 quasar pairs with projected separation < 300 kpc and high dispersion, high S/N spectra, we find extreme kinematics with low metal ion lines typically spanning ~ 500 km/s, exceeding any previously studied galactic population. The CGM is significantly enriched, even beyond the virial radius, with a median metallicity [M/H] ~ -0.6. The alpha/Fe abundance ratio is enhanced, suggesting that halo gas is primarily enriched by core-collapse supernovae. The projected cool gas mass within the virial radius is estimated to be 1.9*10^11 M_sun (R_\perp/160 kpc)^2, accounting for ~ 1/3 of the galaxy halo baryonic budget. The ionization state of CGM gas increases with projected distance from the foreground quasars, contrary to expectation if the quasar dominates the ionizing radiation flux. However, we also found peculiarities not exhibited in the CGM of other galaxy populations. In one absorption system, we may be detecting unresolved fluorescent Ly-alpha emission, and another system shows strong NV lines. Taken together these anomalies suggest that transverse sightlines are at least in some cases possibly illuminated. We also discovered a peculiar case where detection of the CII* fine structure line implies an electron density > 100 cm^-3 and subparsec scale gas clumps.

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References
How the literature uses it

5 arXiv papers cite this in 20 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 12 sentences without a confident label

Uses its data or values 1 paper
  • SB_Lyα^thin = 8.8×10^-20(1+z/3.253)^-4 (n_H/0.01 cm^-3) × (f_C^thin/0.5) (N_H/10^20.5 cm^-2), where we used the redshift of our observations ($z=2.253$), the median value for the column density $N_H$ found in absorption studies ( [ref] ) and an expected value for the volume density $n_H$ from simulation on such scales (e.g. 160 kpc; [ref] ).

    The Stacked Lyman-Alpha Emission Profile from the Circum-Galactic Medium of z~2 Quasars · Discussion · 0.97

Compares with it 2 papers
Cites it as support 1 paper
  • This result, together with the absence of fluorescent emission from these optically thick absorbers ( [ref] ) as well as photoionization modeling of individual absorbers ( [ref] ) all indicate a scenario in which the optically thick gas observed in absorption toward background sightlines is shadowed from the ionizing radiation of the quasar.

    The Stacked Lyman-Alpha Emission Profile from the Circum-Galactic Medium of z~2 Quasars · Discussion · 0.99

Cites it as background 1 paper

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