Pith. sign in

REVIEW 2 major objections 4 minor 1 cited by

Figuring Out Gas & Galaxies in Enzo (FOGGIE). XV. Examining the Spatial and Kinematic Relationship between Circumgalactic Mg II and O VI

T0 review · 2 major / 4 minor · reviewed 2026-08-03 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read Using high-resolution galaxy simulations, this paper argues that apparent co-kinematic Mg II and O VI absorbers in circumgalactic sightlines can be a line-of-sight coincidence rather than co-moving gas.

desk verdict Potentially important selection-effect claim about co-kinematic MgII-OVI pairs, but the missing random-pairing null test keeps the central conclusion from being demonstrated. read the letter →

arxiv 2601.02348 v2 pith:6JX2K4ES submitted 2026-01-05 astro-ph.GA

Mackenzie Ticoras , Brian W. O'Shea , Claire Kopenhafer , Cassandra Lochhaas , Molly S. Peeples , Jason Tumlinson , Cameron Trapp , Vida Saeedzadeh
show 4 more authors
Ramona Augustin Nicolas Lehner Britton D. Smith J. Christopher Howk
This is my paper
classification astro-ph.GA
keywords circumgalacticmediumMgIIOVIabsorption-linekinematicshydrodynamicsimulationsFOGGIEcoveringfractionmockabsorbers
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper tries to establish that the observed kinematic alignment between low-ion (Mg II) and high-ion (O VI) gas in galaxy halos can be a selection effect rather than evidence of co-moving structures. Using the FOGGIE cosmological zoom-in simulations of Milky Way-mass galaxies, it shows that O VI forms a diffuse extended halo while Mg II is concentrated near the disk. The key finding is that when absorber pairs are chosen by their closest line-of-sight velocity—the same selection used in observational work—Mg II and O VI appear co-kinematic, but those pairs are not spatially close. Looking at all absorber pairs or physically closest pairs reveals a much weaker correlation. If true, this means observational inferences about cool and warm gas sharing the same structures may need to be reconsidered.

What carries the argument

The central device is the SALSA package, which identifies individual spatially and kinematically contiguous overdensities (mock absorbers) along one-dimensional rays through the FOGGIE simulations. The decisive comparison is a set of cumulative distributions of velocity difference between Mg II and O VI absorber pairs under four pair-selection rules: all pairs, the physically closest pair per ray, the highest-column-density pair, and the closest-velocity pair. The gap between the closest-velocity distribution (which reproduces the observational co-kinematic signal) and the physically-closest and all-pairs distributions is what carries the argument.

What would settle it

Run the same SALSA absorber-pair analysis on synthetic data in which Mg II and O VI are placed in spatially uncorrelated distributions that match their individual radial profiles: if the closest-velocity CDF still puts most pairs within 35 km/s, the selection-effect mechanism is confirmed; if the signal disappears, the paper's explanation is wrong. A second check is to fit synthetic spectra with standard absorption-line software and see whether the co-kinematic signal survives.

Watch

Extended reading notes

Core claim

The paper's central claim is that Mg II and O VI absorber pairs appear kinematically correlated only when one selects the pair with the smallest line-of-sight velocity difference, as was done in observational work like Werk et al. (2016). These closest-velocity pairs are not generally the closest in physical distance, and when all absorber pairs are considered, the correlation is much weaker. The authors interpret this as a line-of-sight selection effect: with many absorbers along a single sightline, an observer will almost always find a low-ion and high-ion pair within tens of km/s by chance even if the gas structures are far apart. They also show that O VI-bearing gas exists as a diffuse,

Load-bearing premise

The results assume that the post-processing ionization model—using a specific UV background and solar abundances—correctly predicts where Mg II and O VI live; the paper itself notes that a different UV background can substantially change the ionic column densities.

Editorial extensions

If this is right

  • Velocity-proximate Mg II and O VI pairs in single-sightline observations should not be read as evidence that cool and warm gas are co-moving or co-spatial.
  • Detectable O VI should be common across most of the virial radius, while detectable Mg II should be confined to roughly the inner 0.3 Rvir, so joint detections are rare beyond that.
  • The diffuse O VI halo adds substantial integrated column density without forming discrete absorbers, predicting broad O VI line profiles from Doppler broadening.
  • These qualitative results hold across six independent Milky Way-mass halos and from z=3 to z=0.
  • Analysis methods that identify discrete absorbers will systematically undercount O VI compared with integrated column-density methods because diffuse O VI contributes strongly to the total signal.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the velocity-coincidence explanation generalizes, published claims that low-ion and high-ion absorbers co-rotate or trace the same structures may be partly a line-of-sight artifact.
  • The same pair-selection test could be run for other ion pairs (e.g., C IV with H I) in FOGGIE or other simulations; a similar result would broaden the consequence beyond Mg II/O VI.
  • A stronger test would be to generate synthetic absorption spectra from the simulations and fit them with the same pipelines used on real data; if the co-kinematic signal survives standard fitting, the interpretation would need revision.
  • Because the claimed effect depends on having many absorbers per ray, it is likely stronger along long sightlines through massive halos and weaker for galaxies with sparse CGM.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 4 minor

Summary. This paper uses the FOGGIE cosmological zoom-in simulations to investigate the spatial and kinematic relationship between Mg II (low-ion tracer) and O VI (high-ion tracer) in the circumgalactic medium of Milky-Way-mass galaxies. Two complementary methods are used: (i) two-dimensional projected mock sightlines that measure integrated column densities, and (ii) one-dimensional SALSA mock absorbers that identify physically and kinematically contiguous gas structures. The authors find that Mg II is centrally concentrated while O VI forms a diffuse extended halo, and that the covering fractions and detection probabilities vary strongly with impact parameter and redshift. The central kinematic claim is that Mg II–O VI absorber pairs selected as the closest in line-of-sight velocity per ray appear co-kinematic, mimicking the Werk et al. (2016) result, but these pairs are not necessarily the physically closest absorbers; the paper interprets this as a selection effect whereby unrelated absorbers can appear co-kinematic by chance.

Significance. If the central claim holds, the paper would have a valuable cautionary message for CGM absorption-line studies: apparent velocity alignment between low and high ions may not indicate co-moving or co-spatial gas, and selection effects in absorber-pair matching must be considered. The paper's strengths are its use of high-resolution FOGGIE simulations, the explicit comparison of two mock-observation methods, the transparency about model dependencies (UV background, ionization tables, SALSA parameters), and its reliance on publicly available codes (Enzo, Trident, SALSA, yt). The qualitative spatial results (Mg II central, O VI extended) are robust across halos and redshifts. However, the key selection-effect interpretation currently rests on a comparison of CDFs under different selection criteria rather than on a statistical null test, which leaves the central claim under-supported.

major comments (2)
  1. [Section 5.2, Figure 8] The paper's central interpretation—that the closest-velocity Mg II–O VI pairs are a selection effect and are 'physically unrelated'—is not demonstrated by the CDF comparison in Figure 8. The red curve is, by construction, the minimum |Δv| over all pairs along a ray; if a ray contains many O VI and several Mg II absorbers, the minimum will be small even if the two ion populations are randomly distributed in velocity. The orange curve selects by a different criterion (minimum spatial separation). Showing that these two selections give different velocity CDFs does not test whether the observed minimum-velocity distribution is consistent with random pairing. I recommend adding a null test: for each ray, randomly permute the velocities of one ion species (or pair Mg II and O VI absorbers at random) while keeping the ray's absorber numbers fixed, and compute the distribution of the minimum |Δv
  2. [Section 5.2, Figure 8] The comparison to Werk et al. (2016) is not quantitatively calibrated. The blue vertical line at 35 km/s represents the statement that about 80% of O VI absorbers have a low-ion absorber within 35 km/s in the observed sample. But the red curve in Figure 8 is the minimum |Δv| over all pairs along a given simulated ray; the distribution of this minimum depends on the number of Mg II and O VI absorbers per ray (more absorbers naturally produce smaller minima). Unless the simulation is compared to observations using an identical pair-matching algorithm and accounting for the number of absorbers per sightline, the statement that the red curve is 'broadly consistent' with Werk et al. lacks quantitative backing. The authors should either (a) apply the same matching criteria as Werk et al. to the simulations, or (b) present the CDF of the minimum from a null model with the same ray-by-ray multip
minor comments (4)
  1. [General] Typos and grammatical slips should be corrected: 'Th probability' (Section 4.1), 'simualtions' (Section 2.1), 'withing' (Figure 5 caption), and 'the the' (Section 5.3).
  2. [Figure 8] The CDF curves appear to be computed by pooling all halos and rays, but no uncertainties (e.g., bootstrap or halo-to-halo scatter) are shown. Given that the central interpretation rests on differences among these CDFs, error estimates would strengthen the claims.
  3. [Section 4.2 / Figure 7] The statement that Mg II and O VI are 'not as correlated' as in observations is supported only qualitatively by a 2D histogram. A quantitative correlation statistic (e.g., Spearman rank coefficient for distance difference vs. velocity difference) would be useful and easy to add.
  4. [Section 5.4, caveat 4] The statement that changing the column-density threshold would not change the qualitative trends is plausible given the shapes of the CDFs in Figure 3, but it is not shown. A brief test (e.g., repeating Figure 4 or Figure 6 with a different threshold) would make this caveat more compelling.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the central selection-effect claim is an empirical comparison of simulation measurements, not a fitted or self-referential prediction.

full rationale

The paper's central kinematic claim is that Mg II and O VI absorbers appear co-kinematic only when selecting the closest-velocity pair per sightline, but that this does not imply spatial proximity. This is presented as a comparison of four CDFs constructed from SALSA mock absorbers: all pairs, physically closest pairs, largest-column pairs, and closest-velocity pairs. The velocity differences and spatial separations are measured directly from simulation cells; neither quantity is fitted to the other, and the closest-velocity selection is not defined in terms of the spatial-separation result. The authors explicitly describe the effect as a selection effect ('we are seeing selection effect where absorbers that are in no way physically related appear to be co-kinematic'), so the paper is not hiding a tautology as a discovery. The absence of a random-pairing null test is a methodological limitation and a potential statistical-validity concern, but it is not circularity: the paper does not claim to derive the null distribution from its inputs. The ionization modeling uses the external Trident/CLOUDY framework with stated assumptions (Haardt & Madau 2012 UV background, solar abundances), and the paper openly caveats that the UV background can affect ionic column densities; this is model dependence, not a fitted-input-called-prediction. Self-citations to FOGGIE and SALSA papers support simulation provenance and code methodology but are not load-bearing for the central claim, and no uniqueness theorem or ansatz is smuggled in via self-citation. No parameter is fitted to external data and then renamed as a prediction. The derivation chain is therefore self-contained for the claims made, and no specific circular step can be quoted.

Assumptions & free parameters 4 free parameters · 5 assumptions · 0 invented entities

The analysis introduces no new physical entities. Free parameters are thresholds and SALSA algorithm settings chosen by hand; they are not fitted to data. The domain assumptions are the simulation physics, ionization post-processing, and the representativeness of six halos. The most fragile is the UV-background/photoionization assumption, which the paper itself notes has a large effect on ionic column densities.

free parameters (4)
  • Ion column density threshold N_thresh = 10^12.5 cm^-2
    Used to define 'observable' MgII and OVI column densities in Figures 3, 4, and 9; chosen to approximate observational sensitivity, not fitted. The paper asserts qualitative robustness to this choice in Section 5.4 without quantitative sensitivity analysis.
  • SALSA minimum absorber column density = 10^12.5 cm^-2
    Changed from SALSA default 10^13 cm^-2 to match the paper's threshold (Appendix A). Affects absorber identification rates.
  • SALSA column-density fraction threshold = 80%
    SALSA identifies absorbers as contiguous segments above 80% of remaining column density (Appendix A). Default parameter; not varied.
  • SALSA velocity merge threshold = 10 km/s
    SALSA merges adjacent absorber candidates with line-of-sight velocity difference <10 km/s (Appendix A). Default parameter; affects the number and size of mock absorbers.
assumptions (5)
  • domain assumption Trident/CLOUDY post-processing with Haardt & Madau (2012) UV background and solar abundances accurately predicts MgII and OVI column densities.
    Paper post-processes simulation cells with Trident/CLOUDY; Section 5.4 cites Taira et al. (2025) showing UV background choice strongly affects ionic column densities.
  • domain assumption The FOGGIE simulations, which lack magnetic fields, cosmic rays, and AGN feedback, still capture the spatial/kinematic relationship of cool and warm CGM gas.
    Section 5.4 caveat 1 explicitly lists missing physics and notes they may affect CGM structure; the central claim depends on them not changing the qualitative result.
  • ad hoc to paper The chosen column density threshold N=10^12.5 cm^-2 is representative of observational sensitivity, and changing it would not alter qualitative trends.
    Section 3 sets the threshold; Section 5.4 caveat 4 asserts robustness but does not test it.
  • domain assumption SALSA absorber identification with default parameters (80% column threshold, 10 km/s velocity merge) identifies physically meaningful absorbers.
    Appendix A defines algorithm; caveat 5 asserts robustness but no sensitivity analysis is shown.
  • domain assumption Six FOGGIE halos are representative of Milky Way-mass galaxies and the trends generalize beyond this sample.
    Section 5.4 caveat 2: limited sample size and mass range; affects scalability of the conclusions.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Figuring Out Gas & Galaxies in Enzo (FOGGIE). XV. Examining the Spatial and Kinematic Relationship between Circumgalactic Mg II and O VI." pith.science (2026). https://pith.science/paper/6JX2K4ES

@misc{pith2026260102348,
  author       = {Pith},
  title        = {Pith review of: Figuring Out Gas & Galaxies in Enzo (FOGGIE). XV. Examining the Spatial and Kinematic Relationship between Circumgalactic Mg II and O VI},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/6JX2K4ES}},
  note         = {Machine review of arXiv:2601.02348}
}
read the original abstract

Understanding the thermodynamic properties of the circumgalactic medium (CGM) is key to uncovering the baryon cycle in galaxies. Here we present spatial and kinematic relationships between Mg II and O VI as representatives for low and high ion-bearing gas, in the cosmological zoom-in galaxy simulation suite FOGGIE, a set of Milky-way-like galaxy simulations with high CGM resolution. We find the O VI-bearing gas exists as a diffuse halo around the galactic disk, while the Mg II-bearing gas is more centrally located. We investigate the covering fraction, probability of co-observation, co-kinematic correspondence of these ions using two different analysis methods. We make both mock sightlines using two-dimensional projections of our simulations treating these cells as integrated lines of sight and we create one-dimensional ray objects and use the SALSA (Boyd et al. 2020) code to investigate individual gas structures that contribute most to the line of sight column densities, which we call mock absorbers. We explore the relative kinematics of these mock absorbers and find Mg II and O VI appear to have a co-kinematic relationship when looking at absorber pairs with the closest relative velocity like in Werk et al. (2016). However, this does not necessarily correspond with a close spatial separation meaning many O VI and Mg II absorber pairs only appear to be co-kinematic but are physically unrelated. Taking a more holistic look at Mg II and O VI absorber pairs reveals a much weaker correlation between these two ions.

Figures

Figures reproduced from arXiv: 2601.02348 by the authors.

Figure 1
Figure 1. All four panels show a projection of one of the FOGGIE galaxies (Blizzard) at z = 0. Left to right: 1) A projection of total gas density, represented as a column density in cm−2 . 2) A projection of Mg II column density with only column densities greater than the threshold of N = 1012.5 cm−2 shown. 3) A projection of O VI column density with only column densities greater than the threshold of N = 1012.5 cm−2 shown. … view at source ↗
Figure 2
Figure 2. Median column density versus impact parameter for the two-dimensional mock sightline datasets at redshifts z = 3, 2, 1, 0.5, and 0. We have normalized our impact parameter, b, by the virial radius, Rvir. The orange lines represent the total gas column density, the blue line represents the Mg II column density, and the pink line represents the O VI column density. Each line is the average across 10 orientations (the … view at source ↗
Figure 3
Figure 3. Cumulative distribution functions (CDF) of Mg II (blue) and O VI (pink) column density values. The black vertical line represents our observable threshold of N = 1012.5 cm−2 . As an annotation, we report the percent of mock sightlines that contain Mg II and O VI column densities above the threshold as averaged across all of six FOGGIE halos at each redshift. Each line represents the average across 10 orientations fo… view at source ↗
Figures from the paper (6 more)
Figure 4
Figure 4. Figure 4: Probability of a projected mock sightline containing column densities of only Mg II, only O VI, or both above the threshold of N = 1012.5 cm−2 as a function of impact parameter. The orange represents the probability of both being observed, the blue represents the proba…
Figure 5
Figure 5. Figure 5: Two-dimensional slice plots through the FOGGIE galaxy Blizzard at z = 0 aligned with a one-dimensional SALSA ray that passes through the dataset (marked as the black vertical line through x = 0). All four images from left to right show the same ray with slices in the t…
Figure 6
Figure 6. Figure 6: Th probability of detecting just Mg II mock absorbers, just O VI mock absorbers, or both mock absorbers within a ray as a function of impact parameter. The orange represents the probability of a ray having both mock absorbers, the blue represents the probability a ray …
Figure 7
Figure 7. Figure 7: Two-dimensional histogram of the distance between pairs of Mg II and O VI mock absorbers and the column density weighted average line-of-sight velocity of these mock absorber pairs. All pairs are limited to the same ray, but if a single ray contains multiple Mg II and …
Figure 8
Figure 8. Figure 8: Cumulative distribution functions (CDF) of velocity difference between Mg II and O VI mock absorber pairs. The blue vertical line represents the 80% of O VI absorbers being within 35 km/s of a low ion absorber. We consider 4 different “cutoffs” for our CDFs: we look at…
Figure 9
Figure 9. Figure 9: Comparison of the probability of detection for our two different analysis methods, the two-dimensional mock sightlines grids and the the one-dimensional SALSA mock absorber analysis. The solid lines above represent the two-dimensional integrated mock sightline analysis…

Discussion (0). Sign in to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. CRexit observed: probing cosmic ray transport in the circumgalactic medium with absorption line spectra

    astro-ph.GA 2026-07 conditional novelty 6.5 of 10

    Efficient cosmic-ray transport in CR-pressure-dominated CGM simulations produces stronger cool-gas absorption (MgII, SiII) and covering fractions matching star-forming galaxies, while slow transport underproduces them.

Reference graph

Works this paper leans on

47 extracted references · 9 canonical work pages · cited by 1 Pith paper

  1. [1]

    2025, Claude (Opus family), https://www.anthropic.com/ Astropy Collaboration, Robitaille, T

    Anthropic. 2025, Claude (Opus family), https://www.anthropic.com/ Astropy Collaboration, Robitaille, T. P., Tollerud, E. J., et al. 2013, A&A, 558, A33, doi: 10.1051/0004-6361/201322068 Astropy Collaboration, Price-Whelan, A. M., Sip˝ ocz, B. M., et al. 2018, AJ, 156, 123, doi: 10.3847/1538-3881/aabc4f

    doi:10.1051/0004-6361/201322068 2025

  2. [2]

    I., Silvia, D

    Boyd, B. I., Silvia, D. W., O’Shea, B. W., et al. 2020, Journal of Open Source Software, 5, 2581, doi: 10.21105/joss.02581

    work page doi:10.21105/joss.02581 2020

  3. [3]

    2019, Journal of Open Source Software, 4, 1636, doi: 10.21105/joss.01636

    Brummel-Smith, C., Bryan, G., Butsky, I., et al. 2019, Journal of Open Source Software, 4, 1636, doi: 10.21105/joss.01636

    doi:10.21105/joss.01636 2019

  4. [4]

    L., Norman, M

    Bryan, G. L., Norman, M. L., O’Shea, B. W., et al. 2014, The Astrophysical Journal Supplement Series, 211, 19, doi: 10.1088/0067-0049/211/2/19

    doi:10.1088/0067-0049/211/2/19 2014

  5. [5]

    S., Werk, J

    Butsky, I. S., Werk, J. K., Tchernyshyov, K., et al. 2022, The Astrophysical Journal, 935, 69, doi: 10.3847/1538-4357/ac7ebd

    doi:10.3847/1538-4357/ac7ebd 2022

  6. [6]

    Cen, R., & Ostriker, J. P. 1992, The Astrophysical Journal, 399, L113, doi: 10.1086/186620 —. 2006, The Astrophysical Journal, 650, 560, doi: 10.1086/506505

    doi:10.1086/186620 1992

  7. [7]

    L., et al

    Chen, H.-W., Wild, V., Tinker, J. L., et al. 2010, The Astrophysical Journal, 724, L176, doi: 10.1088/2041-8205/724/2/L176

    doi:10.1088/2041-8205/724/2/l176 2010

  8. [8]

    2025, The Astrophysical Journal, 981, 81, doi: 10.3847/1538-4357/ada942

    Chen, Z., Wang, E., Zou, H., et al. 2025, The Astrophysical Journal, 981, 81, doi: 10.3847/1538-4357/ada942

    doi:10.3847/1538-4357/ada942 2025

Show all 47 references
  1. [9]

    F., Zabl, J., et al

    Cherrey, M., Bouch´ e, N. F., Zabl, J., et al. 2025, Astronomy & Astrophysics, 694, A117, doi: 10.1051/0004-6361/202451165

    2025 doi

  2. [10]

    S., Tumlinson, J., et al

    Corlies, L., Peeples, M. S., Tumlinson, J., et al. 2020, The Astrophysical Journal, 896, 125, doi: 10.3847/1538-4357/ab9310

    2020 doi

  3. [11]

    2025, The Astrophysical Journal, 985, 44, doi: 10.3847/1538-4357/adc922

    Dutta, S., Muzahid, S., Schaye, J., et al. 2025, The Astrophysical Journal, 985, 44, doi: 10.3847/1538-4357/adc922

    2025 doi

  4. [12]

    L., & Mac Low, M.-M

    Emerick, A., Bryan, G. L., & Mac Low, M.-M. 2019, Monthly Notices of the Royal Astronomical Society, 482, 1304, doi: 10.1093/mnras/sty2689

    2019 doi

  5. [13]

    J., Porter, R

    Ferland, G. J., Porter, R. L., van Hoof, P. A. M., et al. 2013, RMxAA, 49, 137, doi: 10.48550/arXiv.1302.4485

    2013 doi arXiv

  6. [14]

    J., Frazer, E

    Fox, A. J., Frazer, E. M., Bland-Hawthorn, J., et al. 2020, The Astrophysical Journal, 897, 23, doi: 10.3847/1538-4357/ab92a3

    2020 doi

  7. [15]

    2012, The Astrophysical Journal, 746, 125, doi: 10.1088/0004-637X/746/2/125

    Haardt, F., & Madau, P. 2012, The Astrophysical Journal, 746, 125, doi: 10.1088/0004-637X/746/2/125

    2012 doi

  8. [16]

    H., et al

    Helmi, A., Babusiaux, C., Koppelman, H. H., et al. 2018, Nature, 563, 85, doi: 10.1038/s41586-018-0625-x

    2018 doi

  9. [17]

    2025, Kinematics of Circumgalactic O VI Gas and Disk Rotation of$z\approx0.2$Star-forming Galaxies, arXiv, doi: 10.48550/arXiv.2507.11664

    Stern, J. 2025, Kinematics of Circumgalactic O VI Gas and Disk Rotation of$z\approx0.2$Star-forming Galaxies, arXiv, doi: 10.48550/arXiv.2507.11664

    2025 doi

  10. [18]

    B., Smith, B

    Hummels, C. B., Smith, B. D., & Silvia, D. W. 2017, ApJ, 847, 59, doi: 10.3847/1538-4357/aa7e2d

    2017 doi

  11. [19]

    B., Smith, B

    Hummels, C. B., Smith, B. D., Hopkins, P. F., et al. 2019, The Astrophysical Journal, 882, 156, doi: 10.3847/1538-4357/ab378f

    2019 doi

  12. [20]

    Hunter, J. D. 2007, Computing in Science and Engineering, 9, 90, doi: 10.1109/MCSE.2007.55

    2007 doi

  13. [21]

    C., & Wakker, B

    Lehner, N., Howk, J. C., & Wakker, B. P. 2015, The Astrophysical Journal, 804, 22, doi: 10.1088/0004-637X/804/2/79

    2015 doi

  14. [22]

    M., Fox, A

    Lehner, N., O’Meara, J. M., Fox, A. J., et al. 2014, The Astrophysical Journal, 788, 119, doi: 10.1088/0004-637X/788/2/119

    2014 doi

  15. [23]

    C., Howk, J

    Lehner, N., Berek, S. C., Howk, J. C., et al. 2020, The Astrophysical Journal, 900, 9, doi: 10.3847/1538-4357/aba49c

    2020 doi

  16. [24]

    M., et al

    Lehner, N., Kopenhafer, C., O’Meara, J. M., et al. 2022, The Astrophysical Journal, 936, 156, doi: 10.3847/1538-4357/ac7400

    2022 doi

  17. [25]

    C., Collins, L., et al

    Lehner, N., Howk, J. C., Collins, L., et al. 2025, Project AMIGA: The Inner Circumgalactic Medium of Andromeda from Thick Disk to Halo, arXiv, doi: 10.48550/arXiv.2506.16573

    2025 doi arXiv

  18. [26]

    W., Kacprzak, G

    Marra, R., Churchill, C. W., Kacprzak, G. G., et al. 2023, Monthly Notices of the Royal Astronomical Society, 527, 10522, doi: 10.1093/mnras/stad3735 FOGGIE XV: Circumgalactic MgIIand OVI15

    2023 doi

  19. [27]

    W., Doughty, C., et al

    Marra, R., Churchill, C. W., Doughty, C., et al. 2021, Monthly Notices of the Royal Astronomical Society, 508, 4938, doi: 10.1093/mnras/stab2896 OpenAI. 2025, ChatGPT, https://chat.openai.com/

    2021 doi

  20. [28]

    S., Corlies, L., Tumlinson, J., et al

    Peeples, M. S., Corlies, L., Tumlinson, J., et al. 2019, The Astrophysical Journal, 873, 129, doi: 10.3847/1538-4357/ab0654 P´ eroux, C., & Howk, J. C. 2020, Annual Review of Astronomy and Astrophysics, 58, 363, doi: 10.1146/annurev-astro-021820-120014

    2019 doi

  21. [29]

    N., & Liu, J

    Qu, Z., Pan, Z., Bregman, J. N., & Liu, J. 2024, ApJ, 965, 100, doi: 10.3847/1538-4357/ad31a0

    2024 doi

  22. [30]

    D., et al

    Qu, Z., Chen, H.-W., Johnson, S. D., et al. 2024, The Astrophysical Journal, 968, 8, doi: 10.3847/1538-4357/ad410b

    2024 doi

  23. [31]

    C., et al

    Sameer, Lehner, N., Howk, J. C., et al. 2024, The COS CGM Compendium V: The Dichotomy of OVI Associated with Low- and High-Metallicity Cool Gas at z <1, arXiv, doi: 10.48550/arXiv.2403.02374

    2024 doi arXiv

  24. [32]

    C., Peeples, M

    Simons, R. C., Peeples, M. S., Tumlinson, J., et al. 2020, The Astrophysical Journal, 905, 167, doi: 10.3847/1538-4357/abc5b8

    2020 doi

  25. [33]

    D., Hallman, E

    Smith, B. D., Hallman, E. J., Shull, J. M., & O’Shea, B. W. 2011, The Astrophysical Journal, 731, 6, doi: 10.1088/0004-637X/731/1/6

    2011 doi

  26. [34]

    D., Bryan, G

    Smith, B. D., Bryan, G. L., Glover, S. C. O., et al. 2017, Monthly Notices of the Royal Astronomical Society, 466, 2217, doi: 10.1093/mnras/stw3291

    2017 doi

  27. [35]

    T., Keeney, B

    Stocke, J. T., Keeney, B. A., Danforth, C. W., et al. 2013, The Astrophysical Journal, 763, 148, doi: 10.1088/0004-637X/763/2/148

    2013 doi

  28. [36]

    R., et al

    Strawn, C., Roca-F` abrega, S., Primack, J. R., et al. 2024, The Astrophysical Journal, 962, 29, doi: 10.3847/1538-4357/ad12cb

    2024 doi

  29. [37]

    2019, Monthly Notices of the Royal Astronomical Society, 483, 4040, doi: 10.1093/mnras/sty3402

    Hernquist, L. 2019, Monthly Notices of the Royal Astronomical Society, 483, 4040, doi: 10.1093/mnras/sty3402

    2019 doi

  30. [38]

    W., et al

    Taira, E., Kopenhafer, C., O’Shea, B. W., et al. 2025, The Astrophysical Journal, 991, 221, doi: 10.3847/1538-4357/adfc4e

    2025 doi

  31. [39]

    M., Sembach, K

    Tripp, T. M., Sembach, K. R., Bowen, D. V., et al. 2008, The Astrophysical Journal Supplement Series, 177, 39, doi: 10.1086/587486

    2008 doi

  32. [40]

    S., & Werk, J

    Tumlinson, J., Peeples, M. S., & Werk, J. K. 2017, Annual Review of Astronomy and Astrophysics, 55, 389, doi: 10.1146/annurev-astro-091916-055240

    2017 doi

  33. [41]

    J., Smith, B

    Turk, M. J., Smith, B. D., Oishi, J. S., et al. 2011, The Astrophysical Journal Supplement Series, 192, 9, doi: 10.1088/0067-0049/192/1/9 van de Voort, F., Bieri, R., Pakmor, R., et al. 2021, Monthly Notices of the Royal Astronomical Society, 501, 4888, doi: 10.1093/mnras/staa...

    2011 doi

  34. [42]

    E., et al

    Virtanen, P., Gommers, R., Oliphant, T. E., et al. 2020, Nature Methods, 17, 261, doi: 10.1038/s41592-019-0686-2

    2020 doi

  35. [43]

    Walt, S. v. d., Colbert, S. C., & Varoquaux, G. 2011, Computing in Science & Engineering, 13, 22

    2011

  36. [44]

    2025, Astronomy & Astrophysics, 698, A125, doi: 10.1051/0004-6361/202553954

    Weber, M., Thomas, T., Pfrommer, C., & Pakmor, R. 2025, Astronomy & Astrophysics, 698, A125, doi: 10.1051/0004-6361/202553954

    2025 doi

  37. [45]

    K., Prochaska, J

    Werk, J. K., Prochaska, J. X., Tumlinson, J., et al. 2014, The Astrophysical Journal, 792, 8, doi: 10.1088/0004-637X/792/1/8

    2014 doi

  38. [46]

    K., Prochaska, J

    Werk, J. K., Prochaska, J. X., Cantalupo, S., et al. 2016, The Astrophysical Journal, 833, 54, doi: 10.3847/1538-4357/833/1/54

    2016 doi

  39. [47]

    C., Tumlinson, J., Peeples, M

    Wright, A. C., Tumlinson, J., Peeples, M. S., et al. 2024, The Astrophysical Journal 16Ticoras et al. APPENDIX A.ABSORPTION IDENTIFICATION METHODS IN SALSA SALSA uses an iterative method to identify absorbers along a line of sight. First, it finds the total ion column density ...

    2024

Pith tools

Reviewed August 3, 2026 · model on record in the stance chip above.