Pith. sign in

REVIEW 3 major objections 5 minor 1 cited by

Detection of 'super-virial' gas in the Circumgalactic medium of the Milky Way towards PKS 2155-304

T0 review · 3 major / 5 minor · reviewed 2026-08-05 · deepseek-v4-flash

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

Pith's one-line read This paper reports the first simultaneous detection of four distinct highly ionized gas phases in the Milky Way's circumgalactic medium toward the blazar PKS 2155-304, including the first Mg XII K-alpha absorption line ever seen in the Milk

desk verdict A careful, incremental extension of the super-virial CGM program whose strong conclusions rest on two ~2-sigma line detections, one of which conflicts with a more sensitive instrument's upper limit. read the letter →

arxiv 2509.02019 v1 pith:CVKQXW5T submitted 2025-09-02 astro-ph.GA astro-ph.HE

Mukesh Singh Bisht , Sanskriti Das , Smita Mathur , Manami Roy , Yair Krongold , Anjali Gupta This is my paper
classification astro-ph.GAastro-ph.HE
keywords circumgalacticmediumsuper-virialgasX-rayabsorptionlinesMgXIIPKS2155-304MilkyWayhalomultiphasecollisionalionizationequilibrium
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

The paper claims the first simultaneous detection of four distinct temperature phases in the Milky Way's circumgalactic medium (CGM) along a single sightline, using Chandra and XMM-Newton grating spectra toward the blazar PKS 2155-304. It reports the first detection of the Mg XII K-alpha absorption line in the Milky Way CGM, alongside Si XIV, and uses both model-independent line-ratio arguments and the hybrid-ionization PHASE model to infer phases at roughly 5.4×10^7 K (super-virial), 1.8×10^6 K (virial), 2.2×10^5 K (sub-virial), and below 1.7×10^5 K (cool). Because the sightline lies at a southern Galactic latitude (b ≈ -52°), the result places the hottest phase outside the Northern Hemisphere for the first time, implying the super-virial gas is a widespread CGM component rather than a local anomaly. If correct, this supports a multi-peaked, multiphase temperature structure in the Milky Way's halo, with abundance patterns (alpha-element enhancement, super-solar Mg/Si and C/Ne) and kinematic signatures (infalling cool gas, quasi-static virial gas, outflowing hot gas) that constrain models of feedback and circulation.

What carries the argument

The PHASE model: a hybrid collisional-plus-photoionization spectral model that produces Voigt absorption profiles, with free parameters for temperature, equivalent hydrogen column density, elemental abundances (each allowed to vary relative to oxygen), non-thermal broadening, photoionization parameter U, and redshift. With U frozen at its lowest value (10^-3.9), the model simultaneously fits all detected and non-detected lines and decomposes them into three phases: sub-virial, virial, and super-virial. The fourth, cool phase is inferred from the model-independent temperature estimate obtained from the column-density ratio of the O V non-detection to the O IV detection, which places an upper

What would settle it

Take the same Chandra and XMM-Newton spectra and fit them with a non-equilibrium cooling model, or allow the photoionization parameter to float: if a good fit can be obtained without the 5×10^7 K phase, the super-virial interpretation fails. Alternatively, with a future high-resolution X-ray spectrometer, resolve the Mg XII and Si XIV line profiles: if their Doppler b parameters exceed the thermal value at 5×10^7 K by more than the errors, the line widths are dominated by turbulence and the temperature inference collapses.

Watch

Extended reading notes

Core claim

On its own terms, this paper establishes that the z=0 X-ray absorption spectrum of PKS 2155-304 contains at least three, and likely four, thermally distinct phases of the Milky Way's circumgalactic medium. The Mg XII K-alpha absorption line at 8.421 Å, detected at 2.4 sigma with equivalent width 1.47±0.59 mÅ in the ACIS-MEG data, together with the Si XIV line in HRC-LETG, provides the first X-ray absorption evidence of a hot phase at about 5×10^7 K at a southern Galactic latitude. The authors argue that the column-density ratios of adjacent H-like and He-like ions (C VI/C V, O VIII/O VII, Si XIV/Si XIII, and others), under collisional ionization equilibrium, yield temperatures with clear val

Load-bearing premise

The temperature and phase separation rest on the assumption that the absorbing gas is in collisional ionization equilibrium with negligible photoionization, so measured ratios of adjacent ions translate directly into temperatures; non-equilibrium cooling, significant photoionization, or unresolved non-thermal broadening would change the inferred temperatures and could merge or remove the phases.

Editorial extensions

If this is right

  • The super-virial gas at roughly 5×10^7 K exists at southern Galactic latitudes, so it is not a northern-sky artifact; models of the Milky Way's CGM must reproduce this hot phase as a global, inhomogeneous component.
  • Mg XII K-alpha can now be used as a new tracer of the hottest CGM phase in other sightlines, extending the diagnostic suite beyond O VII, O VIII, Ne X, and Si XIV.
  • The coexistence of four phases with temperature valleys between them supports a multi-peaked (log-normal) temperature distribution in the CGM, consistent with multiphase gas expected from feedback and accretion.
  • The kinematic pattern of blue-shifted low-ionization lines (v ≈ -100 km/s), consistent-with-zero virial lines, and red-shifted hot lines indicates simultaneous infall of cool gas, a quasi-static virial phase, and outflow of the super-virial phase along this line of sight.
  • The alpha-enhancement and super-solar abundances in the virial and super-virial phases require a nucleosynthetic source (core-collapse supernovae) that enriches the CGM unevenly, with the hot phase enriched in Mg and Si while the virial phase is enriched in C and Ne.

Reading between the lines

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

  • Because the inferred super-virial column density toward PKS 2155-304 (N_H ≈ 2.5×10^21 cm^-2) is an order of magnitude larger than along previous sightlines, and the sky position is only about 17.7 degrees in Galactic longitude, an extension of the paper's logic is that this line of sight catches an overdense patch or an outflow preferentially directed from the Galactic center; stacking surveys sho
  • The paper fixes the photoionization parameter U at 10^-3.9 and does not report a test with U free; a testable extension is to re-fit the same spectra with U as a free parameter and check whether a photoionized warm component can replace the sub-virial phase without erasing the super-virial detection.
  • The Mg XII and Si XIV detections are at the 2-3 sigma level, so a clean confirmation would come from re-observing the same sightline with a future high-resolution X-ray calorimeter at higher signal-to-noise, resolving the line profiles and measuring both the Doppler temperature and the actual absorption shape.
  • If the hot phase is truly super-virial and alpha-enhanced, its cooling time is long; a direct extension is that the same phase should be visible in absorption in the halos of external galaxies with similar column densities and relative abundances, which would make the 'super-virial' CGM a generic feature of star-forming galaxies.
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

3 major / 5 minor

Summary. This paper analyzes all available Chandra (ACIS-MEG, ACIS-LETG, HRC-LETG) and XMM-Newton (RGS1/RGS2) grating spectra toward PKS 2155-304 to search for z=0 X-ray absorption lines from H- and He-like C, N, O, Ne, Mg, and Si. It reports detections (significance >2σ) of C V, C VI, N VI, O IV, O VII (Kα/β), O VIII, Ne IX, and the first Mg XII Kα detection in the Milky Way CGM, plus a 2.1σ Si XIV detection. From CIE column-density ratios and a three-phase PHASE model, the paper infers four temperature phases: cool (<1.7×10^5 K), sub-virial (2.2×10^5 K), virial (1.8×10^6 K), and super-virial (5.4×10^7 K). It derives non-solar abundances, interprets low-ionization blueshifts and high-ionization redshifts as inflow/outflow, and emphasizes that this sightline lies at southern Galactic latitude (b=-52.2°), extending previous northern detections.

Significance. If the Mg XII and Si XIV detections are real, this is a valuable result: it provides the first southern-hemisphere X-ray absorption evidence for a ~5×10^7 K CGM phase, introduces Mg XII as a tracer, and gives a four-phase temperature ladder that constrains CGM structure. The paper merits credit for combining all archival grating data, comparing with UV O VI and C IV measurements, and checking ISM contamination using XRB sightlines. However, the central super-virial claim rests on two marginal line detections and on instrument choices made after inspecting multiple datasets. The statistical foundation of the main claim is therefore not yet established at the level asserted in the abstract and conclusions.

major comments (3)
  1. [§2.2, Table 1, Table 3] The T3=5.4×10^7 K phase in Table 3 is carried by exactly two line detections: Mg XII Kα (ACIS-MEG, EW=1.47±0.59 mÅ, 2.4σ) and Si XIV Kα (HRC-LETG, EW=3.73±1.75 mÅ, 2.1σ). The paper adopts a >2σ detection threshold while searching ~10 ions × 5 instruments. Under Gaussian noise, ~50 trials at a 2σ cut are expected to produce ~2.5 spurious detections, i.e. the two lines that define T3 are exactly the marginal cases expected from noise. The authors need a trials-corrected significance, a blind false-positive simulation, or a joint fit of all five instruments to these lines. Without such a test, the super-virial phase is not securely detected.
  2. [§2.2-2.3, Tables 1-2] The instrument selection is post hoc and, for Si XIV, inconsistent with the most sensitive instrument. The adopted HRC-LETG Si XIV EW (3.73 mÅ) is not confirmed by ACIS-MEG, which gives a 3σ upper limit of <2.6 mÅ; ACIS-LETG gives <2.5 mÅ. At face value the instrument with the best sensitivity at 6.18 Å excludes the adopted value, and the statement in §2.2 that the non-detections are 'consistent with detection within 1σ' is not supported by the quoted numbers. Similar post hoc choices are made for O VII (ACIS-LETG adopted over larger RGS1/MEG EWs) and Mg XI (MEG upper limit adopted over the RGS2 5.7±1.7 mÅ detection). A pre-specified selection rule or a simultaneous fit to all instruments is required before the phase decomposition can be trusted.
  3. [§2.3-2.4] The cool phase (<1.7×10^5 K) is inferred from a single ratio of one detection (O IV) to one non-detection (O V), under CIE and the assumption that both ions trace the same phase. That ratio is not unique to a thermal plasma: photoionized or recombining gas can produce the same O IV/O V constraint at different temperatures. Similarly, the PHASE model freezes U=10^-3.9 without testing the sensitivity of the inferred T1/T2/T3 values to this assumption. The statement that the model 'successfully reproduces the column densities' is not an independent check, since the same data were used for the fit. These modeling uncertainties are secondary to the statistical issue above, but they affect the four-phase interpretation.
minor comments (5)
  1. [Tables 1-2] N VII Kα is listed as detected in ACIS-LETG (3.2±1.4 mÅ) in Table 1, but Table 2 uses the HRC-LETG upper limit (<5.26 mÅ) with no explanation. Please clarify which measurement is used and why.
  2. [§2.4] The χ2/dof values in the F-test paragraph (5156.53/5617, 5156.55/5618) are not consistent with the final fit χ2/dof of 5156.53/5603 quoted earlier in the same section; a one-parameter freeze should change dof by 1, not 14. Please recompute or correct.
  3. [§2.4 vs §4, Fig. 7] The text reports that the hot-phase line-of-sight velocity is consistent with zero, yet §4 and Fig. 7 discuss the hot gas as outflowing/redshifted. These statements should be reconciled.
  4. [General] Typographical: 'Sixiii' should read 'Si xiii'; Fig. 7 axis label 'OVI,CIV' needs formatting; Fig. 2 caption is difficult to parse for the dashed magenta/purple lines.
  5. [§3.2] Confidence levels for previous sightline parameters are mixed (1σ, 90%, 99.73%) when comparing with the 1σ values of this work; please use consistent confidence levels for quantitative comparisons.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the detections, column densities, and temperature inferences are derived from the measured grating spectra; self-citations are contextual and not load-bearing.

full rationale

The paper's derivation chain is: co-add archival grating spectra; measure absorption-line equivalent widths; convert EWs to column densities; use column-density ratios under collisional ionization equilibrium (CIE) to estimate temperatures; and fit the PHASE model to all detected and non-detected lines. None of these steps defines its conclusion in terms of its inputs. In Sec. 2.3, the model-independent temperatures are conditional inferences from measured ratios (e.g., C VI/C V, O VIII/O VII, Si XIV/Si XIII) under stated CIE assumptions; they are not identities. In Sec. 2.4, the PHASE model parameters are free and fitted to the data; the statement that the final model 'successfully reproduces' observed column densities is a goodness-of-fit description after fitting, not an independent prediction. The paper explicitly rejects simpler models on chi-square grounds, so the four-phase structure is not imposed by construction. The comparisons with UV O VI and C IV from Collins et al. (2004) are external benchmarks not used in the X-ray fit, so their consistency is a genuine, non-circular check. The self-citation to Das (2024) for negligible non-thermal broadening supports a modeling assumption, but it is not the mechanism that produces the super-virial temperature, which is mainly constrained by the high-ionization lines and the PHASE fit. The principal scientific weakness, that Mg XII (2.4 sigma) and Si XIV (2.1 sigma) are marginal detections, is a statistical robustness concern, not a circularity concern. Therefore no circular step meets the required evidence bar.

Assumptions & free parameters 8 free parameters · 5 assumptions · 0 invented entities

The central claim rests on standard astrophysical assumptions (CIE, negligible photoionization, z=0 absorption) applied to spectral fits with many free parameters. No new particles, forces, or invented entities are introduced. The multiple fitted temperatures, column densities, and abundance ratios are the main free parameters that shape the four-phase conclusion.

free parameters (8)
  • T1 (sub-virial phase temperature) = 2.2±0.5e5 K
    Fitted in PHASE model to reproduce C V and N VI column densities; central to the four-phase claim.
  • T2 (virial phase temperature) = 1.8+0.3-0.2e6 K
    Fitted in PHASE model; main warm-hot phase parameter.
  • T3 (super-virial phase temperature) = 5.4+1.9-0.8e7 K
    Fitted in PHASE model to reproduce Mg XII and Si XIV; the key hot-phase claim.
  • N_H1, N_H2, N_H3 (equivalent H column densities) = 1.9e18, 8.8e18, 2.5e21 cm^-2
    Fitted in PHASE model for the three phases; drive the column density predictions.
  • [C/O] and [N/O] in PHASE_A = 0.23+0.24-0.16 and 0.35+0.30-0.42
    Fitted abundance ratios in the virial phase; tied across phases in some cases.
  • [Ne/O] in PHASE_A = 1.02+0.28-0.27
    Fitted abundance ratio for Ne in the virial phase.
  • [Mg/O] and [Si/O] in PHASE_B = 0.43+0.21-0.29 and 0.93+0.22-0.40
    Fitted abundance ratios in the super-virial phase; support the alpha-enhancement claim.
  • [O/Fe], [Ne/Fe], [Mg/Fe], [Si/Fe] = lower limits (e.g., >1.0, >0.72, >1.43, >1.93)
    Fitted/constrained in PHASE model to demonstrate alpha-enhancement.
assumptions (5)
  • domain assumption The absorbing gas is in collisional ionization equilibrium (CIE)
    All model-independent temperature estimates assume CIE (Section 2.3). If the gas is cooling or not in equilibrium, the inferred temperatures are not valid.
  • domain assumption Photoionization is negligible (U frozen at 1e-3.9)
    In the PHASE model (Section 2.4), the photoionization parameter is fixed to its lowest value. If the CGM is significantly photoionized by the extragalactic UV background or other sources, the phase temperatures and column densities would change.
  • domain assumption The absorption is at z=0 (Milky Way CGM), not at the blazar redshift or in the Galactic disk ISM
    The analysis fixes line centers at z=0 and searches for z=0 absorption (Section 2.2). The ISM origin is partially rejected using XRB sightlines (Section 4.2), but the extra-planar/CGM location is an assumption.
  • domain assumption Line broadening is purely thermal (non-thermal broadening insignificant)
    The PHASE model assumes thermal broadening only, citing Das 2024. If non-thermal broadening is present, the derived b-parameter and temperature for O VII (and the model temperatures) would be biased.
  • standard math Abundance ratios are measured relative to the solar abundance standard
    The 'super-solar' and 'alpha-enhanced' claims rely on the assumed solar reference abundances, a standard but unverified assumption in this context.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Detection of 'super-virial' gas in the Circumgalactic medium of the Milky Way towards PKS 2155-304." pith.science (2026). https://pith.science/paper/CVKQXW5T

@misc{pith2026250902019,
  author       = {Pith},
  title        = {Pith review of: Detection of 'super-virial' gas in the Circumgalactic medium of the Milky Way towards PKS 2155-304},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/CVKQXW5T}},
  note         = {Machine review of arXiv:2509.02019}
}
abstract

We present the first simultaneous detection of four distinct highly ionized $z=0$ absorbing phases using Chandra and XMM-Newton grating spectra toward the blazar PKS 2155$\hbox{-}$304. We detect the MgXII K$\alpha$ absorption line for the first time in the circumgalactic medium (CGM) of the Milky Way. Along with MgXII K$\alpha$, we detect SiXIV K$\alpha$ absorption, which are the tell-tale signatures of the hot 'super-virial' gas in the CGM. Both from the model-independent calculations and hybrid-ionization modeling, we infer four phases at distinct temperatures, hot 'super-virial' ($5.4^{+1.9}_{-0.8} \times 10^7$ K), warm-hot 'virial' ($1.8^{+0.3}_{-0.2} \times 10^6$ K), warm 'sub-virial' ($2.2\pm 0.5 \times 10^5$ K), and cool phase ($<1.7 \times 10^5$ K). The warm-hot and hot phases are $\alpha$-enhanced, and [C/O] and [Ne/O] are super-solar in the warm-hot phase, while [Mg/O] and [Si/O] are super-solar in the hot phase. The low-ionization lines are blue-shifted (v$_{\rm los} \approx -100$ km s$^{-1}$), whereas the high-ionization lines are red-shifted. It suggests a scenario of infalling sub-virial, quasi-static virial, and outflowing super-virial phases along this sightline. Earlier studies on individual sightlines were confined to the Northern Hemisphere. Our sightline is located in the Southern hemisphere, demonstrating that hot super-virial gas is also present at Southern Galactic latitudes as well. This confirms a more widespread distribution of the super-virial gas across both hemispheres.

Figures

Figures reproduced from arXiv: 2509.02019 by the authors.

Figure 1
Figure 1. Normalized absorption profile of the detected (green) and non-detected (red) ions. The dotted black vertical line in each panel shows the 𝑧 = 0 value of the line center of the respective ions. The shaded blue region in each panel indicates the resolution element of the respective instrument relative to the 𝑧 = 0 value of the line center of the ion [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Temperature ranges estimated from the column density ratio of two adjacent ions of the same metal probed in X-ray absorption. It clearly shows the multiphase nature of the CGM with temperature valleys (hatched region) in between. The dashed magenta and purple lines show the temperature estimated from the column density ratios of O vi (detected in UV absorptions by Collins et al. 2004), O v (non-detection in this wor… view at source ↗
Figure 3
Figure 3. Individual contribution of different temperature phases for detected ions. The grey color shows the best-fit PHASE model, while blue, green, and red colors show the contribution of sub-virial (𝑇1), virial (𝑇2), and super-virial (𝑇3) phases, respectively. temperature phases. This could be the case along NGC 3783. A large range in the inferred temperature along various sight￾lines also points towards the temperature i… view at source ↗
Figures from the paper (4 more)
Figure 4
Figure 4. Figure 4: Comparison of best-fit temperatures and associated 1𝜎 uncertainties from previous studies along various lines of sight (Mrk 421, green, Das et al. 2021; stacked, grey, Lara-DI et al. 2024a; 1ES 1553+113, yellow, Das et al. 2019b; NGC 3783, red, McClain et al. 2024). Th…
Figure 6
Figure 6. Figure 6: Top panel: The green line shows the normalized spectrum for the Solar abundance ratio of Ne to Fe in the warm-hot phase. Bottom panel: The dotted, dashed, and dashed-dotted red lines show the normalized spectrum for solar abundance ratios of O to Fe, Mg to Fe, and Si t…
Figure 5
Figure 5. Figure 5: Non-solar abundance ratios of C, Ne, Mg, and Si relative to O in the respective phases. 15.0 15.2 15.4 15.6 15.8 16.0 16.2 [Å] 0.8 0.9 1.0 1.1 best-fit [Ne/Fe] |T2 10.4 10.5 10.6 10.7 10.8 10.9 11.0 11.1 [Å] 0.2 0.4 0.6 0.8 1.0 best-fit [O/Fe] |T3 [Mg/Fe] |T3 [Si/Fe] |…
Figure 7
Figure 7. Figure 7: The line of sight velocityb of the detected transitions. The blue and red colors show blueshift and redshift, respectively. The error bars in the respective color indicate the resolution element of the instruments used to detect these ions relative to the best-fit velo…

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. Studying the absorption signatures of H I Lyman-\alpha\ in the warm-hot circumgalactic medium with TNG50

    astro-ph.GA 2026-06 unverdicted novelty 7.0 of 10

    TNG50 shows coronal broad Lyα absorbers from warm-hot CGM have covering fraction ~0.8 for log N_HI ≥13 and dominate ~50% of CGM H I absorbers around MW-like galaxies.

Reference graph

Works this paper leans on

49 extracted references · 24 canonical work pages · cited by 1 Pith paper

  1. [1]

    1999, XSPEC: An X-ray spectral fitting package, Astrophysics Source Code Library, record ascl:9910.005

    Arnaud, K., Dorman, B., & Gordon, C. 1999, XSPEC: An X-ray spectral fitting package, Astrophysics Source Code Library, record ascl:9910.005

    work page 1999

  2. [2]

    2023, ApJ, 952, 41, doi: 10.3847/1538-4357/acd337

    Bhattacharyya, J., Das, S., Gupta, A., Mathur, S., & Krongold, Y. 2023, ApJ, 952, 41, doi: 10.3847/1538-4357/acd337

    work page doi:10.3847/1538-4357/acd337 2023

  3. [3]

    S., Banerjee, P., Nath, B

    Bisht, M. S., Banerjee, P., Nath, B. B., & Shchekinov, Y. 2024a, ApJ, 975, 26, doi: 10.3847/1538-4357/ad77be 14 Bisht et al

    work page doi:10.3847/1538-4357/ad77be

  4. [4]

    S., Nath, B

    Bisht, M. S., Nath, B. B., & Mathur, S. 2024b, ApJ, 975, 49, doi: 10.3847/1538-4357/ad77c0

    work page doi:10.3847/1538-4357/ad77c0

  5. [5]

    D., et al

    Bluem, J., Kaaret, P., Kuntz, K. D., et al. 2022, ApJ, 936, 72, doi: 10.3847/1538-4357/ac8662

    doi:10.3847/1538-4357/ac8662 2022

  6. [6]

    A., Shull, J

    Collins, J. A., Shull, J. M., & Giroux, M. L. 2004, ApJ, 605, 216, doi: 10.1086/382269

    work page doi:10.1086/382269 2004

  7. [7]

    2024, ApJL, 963, L48, doi: 10.3847/2041-8213/ad2a43

    Das, S. 2024, ApJL, 963, L48, doi: 10.3847/2041-8213/ad2a43

    work page doi:10.3847/2041-8213/ad2a43 2024

  8. [8]

    2021, ApJ, 918, 83, doi: 10.3847/1538-4357/ac0e8e

    Das, S., Mathur, S., Gupta, A., & Krongold, Y. 2021, ApJ, 918, 83, doi: 10.3847/1538-4357/ac0e8e

    doi:10.3847/1538-4357/ac0e8e 2021

Show all 49 references
  1. [9]

    2019a, ApJ, 887, 257, doi: 10.3847/1538-4357/ab5846

    Das, S., Mathur, S., Gupta, A., Nicastro, F., & Krongold, Y. 2019a, ApJ, 887, 257, doi: 10.3847/1538-4357/ab5846

    doi

  2. [10]

    2019b, ApJL, 882, L23, doi: 10.3847/2041-8213/ab3b09

    Das, S., Mathur, S., Nicastro, F., & Krongold, Y. 2019b, ApJL, 882, L23, doi: 10.3847/2041-8213/ab3b09

    doi

  3. [11]

    Donahue, M., & Voit, G. M. 2022, PhR, 973, 1, doi: 10.1016/j.physrep.2022.04.005

    2022 doi

  4. [12]

    Draine, B. T. 2011, Physics of the Interstellar and Intergalactic Medium (Princeton University Press)

    2011

  5. [13]

    S., Sharma, P., et al

    Dutta, A., Bisht, M. S., Sharma, P., et al. 2024, MNRAS, 531, 5117, doi: 10.1093/mnras/stae977

    2024 doi

  6. [14]

    J., Soler, J

    Elia, D., Evans, N. J., Soler, J. D., et al. 2025, ApJ, 980, 216, doi: 10.3847/1538-4357/adaeb2

    2025 doi

  7. [15]

    E., & Treves, A

    Falomo, R., Pesce, J. E., & Treves, A. 1993, ApJL, 411, L63, doi: 10.1086/186913 Faucher-Giguère, C.-A., & Oh, S. P. 2023, ARA&A, 61, 131, doi: 10.1146/annurev-astro-052920-125203 Ferland,G.J.,Chatzikos,M.,Guzmán,F.,etal.2017,RMxAA,53, 385, doi: 10.48550/arXiv.1705.10877

    1993 doi arXiv

  8. [16]

    C., Allen, G

    Fruscione, A., McDowell, J. C., Allen, G. E., et al. 2006, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference

    2006

  9. [17]

    6270, Observatory Operations: Strategies, Processes, and Systems, ed

    Series, Vol. 6270, Observatory Operations: Strategies, Processes, and Systems, ed. D. R. Silva & R. E. Doxsey, 62701V, doi: 10.1117/12.671760

    doi

  10. [18]

    2018, MNRAS, 474, 696, doi: 10.1093/mnras/stx2776

    Gatuzz, E., & Churazov, E. 2018, MNRAS, 474, 696, doi: 10.1093/mnras/stx2776

    2018 doi

  11. [19]

    2021, ApJ, 909, 164, doi: 10.3847/1538-4357/abdbb6

    Gupta, A., Kingsbury, J., Mathur, S., et al. 2021, ApJ, 909, 164, doi: 10.3847/1538-4357/abdbb6

    2021 doi

  12. [20]

    2014, Ap&SS, 352, 775, doi: 10.1007/s10509-014-1958-z Gupta,A.,Mathur,S.,Kingsbury,J.,Das,S.,&Krongold,Y.2023, Nature Astronomy, 7, 799, doi: 10.1038/s41550-023-01963-5

    Gupta, A., Mathur, S., Galeazzi, M., & Krongold, Y. 2014, Ap&SS, 352, 775, doi: 10.1007/s10509-014-1958-z Gupta,A.,Mathur,S.,Kingsbury,J.,Das,S.,&Krongold,Y.2023, Nature Astronomy, 7, 799, doi: 10.1038/s41550-023-01963-5

    2014 doi

  13. [21]

    2025, arXiv e-prints, arXiv:2507.13331, doi: 10.48550/arXiv.2507.13331

    Gupta, A., Mathur, S., Kingsbury, J., et al. 2025, arXiv e-prints, arXiv:2507.13331, doi: 10.48550/arXiv.2507.13331

    2025 doi arXiv

  14. [22]

    2017, ApJ, 836, 243, doi: 10.3847/1538-4357/836/2/243

    Gupta, A., Mathur, S., & Krongold, Y. 2017, ApJ, 836, 243, doi: 10.3847/1538-4357/836/2/243

    2017 doi

  15. [23]

    2012, ApJL, 756, L8, doi: 10.1088/2041-8205/756/1/L8

    Gupta, A., Mathur, S., Krongold, Y., Nicastro, F., & Galeazzi, M. 2012, ApJL, 756, L8, doi: 10.1088/2041-8205/756/1/L8

    2012 doi

  16. [24]

    R., Millman, K

    Harris, C. R., Millman, K. J., van der Walt, S. J., et al. 2020, Nature, 585, 357, doi: 10.1038/s41586-020-2649-2

    2020 doi

  17. [25]

    B., & Shelton, R

    Henley, D. B., & Shelton, R. L. 2010, ApJS, 187, 388, doi: 10.1088/0067-0049/187/2/388 —. 2013, ApJ, 773, 92, doi: 10.1088/0004-637X/773/2/92

    2010 doi

  18. [26]

    B., Shelton, R

    Henley, D. B., Shelton, R. L., Cumbee, R. S., & Stancil, P. C. 2015, ApJ, 799, 117, doi: 10.1088/0004-637X/799/2/117 HI4PI Collaboration, Ben Bekhti, N., Flöer, L., et al. 2016, A&A, 594, A116, doi: 10.1051/0004-6361/201629178

    2015 doi

  19. [27]

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

    2007 doi

  20. [28]

    2001, A&A, 365, L1, doi: 10.1051/0004-6361:20000036

    Jansen, F., Lumb, D., Altieri, B., et al. 2001, A&A, 365, L1, doi: 10.1051/0004-6361:20000036

    2001 doi

  21. [29]

    D., et al

    Kaaret, P., Koutroumpa, D., Kuntz, K. D., et al. 2020, Nature Astronomy, 4, 1072, doi: 10.1038/s41550-020-01215-w

    2020 doi

  22. [30]

    S., et al

    Krongold, Y., Nicastro, F., Brickhouse, N. S., et al. 2003, ApJ, 597, 832, doi: 10.1086/378639

    2003 doi

  23. [31]

    D., & Snowden, S

    Kuntz, K. D., & Snowden, S. L. 2000, ApJ, 543, 195, doi: 10.1086/317071

    2000 doi

  24. [32]

    2024a, MNRAS, 531, 3034, doi: 10.1093/mnras/stae1051 —

    Lara-DI, A., Krongold, Y., Mathur, S., et al. 2024a, MNRAS, 531, 3034, doi: 10.1093/mnras/stae1051 —. 2024b, MNRAS, 533, 287, doi: 10.1093/mnras/stae1845

    doi

  25. [33]

    2023, ApJ, 946, 55, doi: 10.3847/1538-4357/acbf40

    Lara-DI, A., Mathur, S., Krongold, Y., Das, S., & Gupta, A. 2023, ApJ, 946, 55, doi: 10.3847/1538-4357/acbf40

    2023 doi

  26. [34]

    2022, Probing the Circumgalactic Medium with X-Ray Absorption Lines (Singapore: Springer Nature Singapore), 1–36, doi: 10.1007/978-981-16-4544-0_112-1

    Mathur, S. 2022, Probing the Circumgalactic Medium with X-Ray Absorption Lines (Singapore: Springer Nature Singapore), 1–36, doi: 10.1007/978-981-16-4544-0_112-1

    2022 doi

  27. [35]

    2017, ApJL, 851, L7, doi: 10.3847/2041-8213/aa991a

    Mathur, S., Nicastro, F., Gupta, A., et al. 2017, ApJL, 851, L7, doi: 10.3847/2041-8213/aa991a

    2017 doi

  28. [36]

    L., Mathur, S., Das, S., Krongold, Y., & Gupta, A

    McClain, R. L., Mathur, S., Das, S., Krongold, Y., & Gupta, A. 2024, MNRAS, 527, 5093, doi: 10.1093/mnras/stad3497

    2024 doi

  29. [37]

    2018, ApJ, 862, 34, doi: 10.3847/1538-4357/aacceb

    Nakashima, S., Inoue, Y., Yamasaki, N., et al. 2018, ApJ, 862, 34, doi: 10.3847/1538-4357/aacceb

    2018 doi

  30. [38]

    2017, A&A, 605, A47, doi: 10.1051/0004-6361/201630336

    Nevalainen, J., Wakker, B., Kaastra, J., et al. 2017, A&A, 605, A47, doi: 10.1051/0004-6361/201630336

    2017 doi

  31. [39]

    2016, ApJL, 828, L12, doi: 10.3847/2041-8205/828/1/L12

    Nicastro, F., Senatore, F., Krongold, Y., Mathur, S., & Elvis, M. 2016, ApJL, 828, L12, doi: 10.3847/2041-8205/828/1/L12

    2016 doi

  32. [40]

    2002, ApJ, 573, 157, doi: 10.1086/340489

    Nicastro, F., Zezas, A., Drake, J., et al. 2002, ApJ, 573, 157, doi: 10.1086/340489

    2002 doi

  33. [41]

    2018, Nature, 558, 406, doi: 10.1038/s41586-018-0204-1

    Nicastro, F., Kaastra, J., Krongold, Y., et al. 2018, Nature, 558, 406, doi: 10.1038/s41586-018-0204-1

    2018 doi

  34. [42]

    2023, A&A, 674, A195, doi: 10.1051/0004-6361/202243992

    Ponti, G., Zheng, X., Locatelli, N., et al. 2023, A&A, 674, A195, doi: 10.1051/0004-6361/202243992

    2023 doi

  35. [43]

    2025a, ApJ, 982, 8, doi: 10.3847/1538-4357/adb3a5

    Roy, M., Mathur, S., Das, S., et al. 2025a, ApJ, 982, 8, doi: 10.3847/1538-4357/adb3a5

    doi

  36. [44]

    2025b, ApJ, 988, 71, doi: 10.3847/1538-4357/ade059

    Roy, M., Su, K.-Y., Mathur, S., & Stern, J. 2025b, ApJ, 988, 71, doi: 10.3847/1538-4357/ade059

    doi

  37. [45]

    2023, PASJ, 75, 1324, doi: 10.1093/pasj/psad073

    Sugiyama, H., Ueda, M., Fukushima, K., et al. 2023, PASJ, 75, 1324, doi: 10.1093/pasj/psad073

    2023 doi

  38. [46]

    S., & Werk, J

    Tumlinson, J., Peeples, M. S., & Werk, J. K. 2017, ARA&A, 55, 389, doi: 10.1146/annurev-astro-091916-055240 Vijayan, A., & Li, M. 2022, MNRAS, 510, 568, doi: 10.1093/mnras/stab3413 Super-virial gas towards PKS 2155-304 15

    2017 doi

  39. [47]

    C., Tananbaum, H

    Weisskopf, M. C., Tananbaum, H. D., Van Speybroeck, L. P., & O’Dell, S. L. 2000, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 4012, X-Ray Optics, Instruments, and Missions III, ed. J. E. Truemper & B. Aschenbach, 2–16, doi: 10.1117/12.391545

    2000 doi

  40. [48]

    J., Mathur, S., Nicastro, F., et al

    Williams, R. J., Mathur, S., Nicastro, F., et al. 2005, ApJ, 631, 856, doi: 10.1086/431343

    2005 doi

  41. [49]

    Y., et al

    Yoshino, T., Mitsuda, K., Yamasaki, N. Y., et al. 2009, PASJ, 61, 805, doi: 10.1093/pasj/61.4.805

    2009 doi

Pith tools

Reviewed August 5, 2026 · model on record in the stance chip above.