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REVIEW 3 major objections 5 minor 59 references

Two of the most metal-poor known galaxies show near-solar iron-to-oxygen ratios, which standard supernova models cannot reproduce.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

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2026-08-02 01:09 UTC pith:6SBGDASL

load-bearing objection New KCWI data confirm high Fe/O in two XMPs, but the abstract oversells it, the quoted uncertainties are too small, and the PISNe/BrHNe attribution outruns the evidence; still worth a serious referee. the 3 major comments →

arxiv 2607.14758 v1 pith:6SBGDASL submitted 2026-07-16 astro-ph.GA

The Mysterious Case of Iron in XMPs: Anomalous High log(Fe/O) Observed in Extremely Metal-Poor Galaxies HSCJ1631+4426 and SDSSJ0811+4730

Aaron Myszka , Themiya Nanayakkara , Karl Glazebrook , Sarah M. Sweet , Brent Groves , Nikole M. Nielsen , Jarle Brinchmann , Yuki Isobe
show 3 more authors
Chiaki Kobayashi Haruka Kusakabe Michael V. Maseda
This is my paper
classification astro-ph.GA
keywords extremely metal-poor galaxiesiron-to-oxygen ratiochemical enrichmentintegral field spectroscopybright hypernovaepair-instability supernovaeFe/O abundance anomalygalaxy abundances
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

This paper aims to establish that two local galaxies with oxygen abundances of only about two percent of the solar value — HSCJ1631+4426 and SDSSJ0811+4730 — nevertheless have iron-to-oxygen ratios close to or above the solar ratio. Given the galaxies' very young ages, a few to fifty million years, ordinary chemical evolution from core-collapse supernovae plus delayed Type Ia supernovae cannot produce so much iron so quickly. The authors argue that the measured points require a prompt, rare iron source, specifically bright hypernovae or pair-instability supernovae, which synthesize large amounts of nickel that decays to iron. If correct, these tiny nearby galaxies become accessible laboratories for studying nucleosynthetic channels thought to operate in the early Universe, and chemical evolution models must incorporate such channels.

Core claim

The paper reports new spatially resolved spectroscopy covering 3545–5529 Å for both galaxies and derives, from the directly detected [FeIII] λ4658 line combined with a literature ionization correction factor, total iron abundances of log(Fe/O) = −1.57 ± 0.17 and −1.28 ± 0.07, alongside oxygen abundances of 12+log(O/H) = 7.079 and 6.926. Placing these values on Fe/O versus oxygen abundance and Fe/O versus age diagrams, the paper finds they lie far above the Milky Way enrichment track and above the region allowed by core-collapse supernova yields plus Type Ia enrichment for ages of 3–50 Myr. The central interpretation is that the iron must come from rare, highly energetic explosions — bright h

What carries the argument

The load-bearing measurement is the [FeIII] λ4658 nebular line, used to derive Fe2+ and then total iron by applying an ionization correction factor that accounts for unobserved Fe3+; in these galaxies the correction is a factor of roughly 7 to 17, so most of the iron is inferred rather than directly seen. The interpretive machinery is the Fe/O ratio placed on two diagnostic planes — Fe/O versus oxygen abundance and Fe/O versus age — where the young ages exclude delayed Type Ia supernovae and the metallicity location excludes standard CCSN tracks. Comparison against chemical evolution tracks for CCSNe, hypernovae, bright hypernovae, and pair-instability supernovae is what isolates the exotic

Load-bearing premise

The result collapses if the ionization correction factor — calibrated under standard star-forming conditions — overestimates the unseen Fe3+ fraction in these harder-radiation galaxies, since 80–94% of the iron is never directly detected and reducing the correction by a factor of two to three lowers log(Fe/O) by up to 0.3 dex.

What would settle it

Determine the true Fe3+/Fe2+ ratio in these two galaxies, either by detecting additional iron ionization stages such as [FeIV] or [FeV], or by constructing a photoionization model that reproduces the observed [OIII]/[OII] ratio and using it to predict the iron correction. If the resulting ICF is two to three times smaller than the literature value, log(Fe/O) falls by up to 0.3 dex and the near-solar Fe/O claim disappears. Separately, measuring the Ar/O and S/O ratios in these galaxies can falsify the pair-instability supernova hypothesis if those ratios match standard core-collapse yields.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • If the result is right, standard chemical evolution models must include prompt iron sources such as bright hypernovae and/or pair-instability supernovae to explain low-metallicity galaxies like these.
  • These two galaxies become nearby, studyable analogues of high-redshift galaxies where recent space-based infrared observations have found elevated nebular Fe/O, offering spatial and spectral detail that distant systems lack.
  • The observed iron overabundance implies that sufficiently massive stars exist at very low metallicity: for a 10^6 solar-mass burst, roughly 170 progenitors above 140 solar masses are expected, so the signal is not a single statistical fluke.
  • Follow-up red-optical spectroscopy targeting argon and sulfur lines can test whether pair-instability supernovae specifically are required or whether bright hypernovae alone suffice, since other XMP studies find argon and sulfur below pair-instability predictions.
  • The new [FeIII] detections are at higher significance than earlier marginal detections, strengthening the empirical footing of the Fe/O values.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The paper's own exploration of an alternative ionization correction lowers log(Fe/O) by 0.23–0.27 dex; if the true correction is even lower, the 'near-solar' framing would weaken, although the residual offset from CCSN-only tracks would likely survive. Directly measuring the Fe3+ fraction would settle this.
  • There is a factor-of-ten age discrepancy between SED-based ages (~50 Myr) and Hβ-equivalent-width ages (~3–4 Myr); the Fe/O–age comparison leans on the young ages, and a firmer age would sharpen or soften the need for exotic prompt sources.
  • If the ICF holds, the implied iron production suggests a top-heavy stellar initial mass function at very low metallicity; this is testable with resolved stellar populations in the nearest extremely metal-poor galaxies.
  • The finding highlights that Fe/O measurements in high-redshift galaxies are only as secure as the ionization corrections used at low metallicity; local XMP analogues are the natural calibrators, so improving the ICF has direct consequences for interpreting early-Universe abundances.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

3 major / 5 minor

Summary. The paper presents new KCWI integral-field spectroscopy of two extremely metal-poor galaxies, HSCJ1631+4426 and SDSSJ0811+4730. Using integrated spectra, the authors derive oxygen abundances via the direct Te method and iron abundances from the single [Fe III] λ4658 line, corrected by the Izotov et al. (2006) ionization correction factor (ICF). They report log(Fe/O) = -1.57 ± 0.17 and -1.28 ± 0.07, respectively, which they describe as approaching or exceeding the solar ratio despite O/H at ~2% solar. They argue that these ratios are inconsistent with enrichment from core-collapse supernovae alone or from delayed Type Ia supernovae given the young ages, and they suggest bright hypernovae (BrHNe) and/or pair-instability supernovae (PISNe) as the likely enrichment channels. The paper is transparent about systematic uncertainties from the ICF choice, atomic data spread, and single-line reliance.

Significance. If the measurements are correct, they provide strong evidence for a non-standard, prompt iron enrichment channel at extremely low metallicity, with direct implications for early-Universe nucleosynthesis and chemical evolution models. The paper's strengths include new spatially resolved KCWI data with improved signal-to-noise on [Fe III] (3.1σ and 6.8σ), explicit Monte Carlo uncertainty propagation, a systematic comparison of [Fe III] atomic datasets, and a candid discussion of the dominant systematics. The analysis uses publicly available packages (PyNeb, LMFIT, astrodendro) and is therefore reproducible in principle. The central anomaly — elevated Fe/O at very low O/H — is robust to the main systematic (ICF choice), but the exact amplitude and the specific BrHNe/PISNe attribution depend on the absolute Fe/O scale and need further scrutiny.

major comments (3)
  1. [§3, Table 2] The central results log(Fe/O) = -1.57 and -1.28 rely on the Izotov et al. (2006) ICF, which multiplies the directly measured Fe2+/H+ by factors of ~7.4 and ~17.2, so 80–94% of the iron is unobserved. The alternative Rodríguez & Rubin (2005) ICF lowers log(Fe/O) by 0.23 and 0.27 dex, giving -1.80 and -1.55. These values do not 'approach or exceed solar' (solar log(Fe/O) = -1.23); HSCJ1631+4426 would be ~0.6 dex below solar. The abstract and summary use the 'approach or exceed solar' phrasing without this caveat. This is not merely cosmetic: the BrHNe/PISNe attribution depends on the absolute Fe/O scale, as the model tracks in Figures 3 and 4 are compared to the adopted ICF values. The paper should explicitly show how the model comparison changes under the alternative ICF, and either temper the 'approach/exceed solar' language or provide a robust justification for preferring the Izotov ICF
  2. [§2, Table 1] The line flux uncertainties are derived from an RMS-based approach that explicitly excludes Poisson noise in bright lines such as Hβ and [O III] λ5007. While the authors argue that the faint [Fe III] λ4658 line is continuum-dominated, the quoted uncertainties on O/H (0.010 and 0.004 dex) and Fe/O (0.17 and 0.07 dex) are propagated from these same RMS uncertainties via 1000 Monte Carlo iterations. The quoted precision on O/H in particular is extremely high and likely underestimated because the strong [O III] lines and Hβ have significant Poisson contributions. Please quantify the impact of adding Poisson errors to the bright lines (e.g., a conservative estimate using the measured line fluxes and counts) to demonstrate that the conclusions and the claimed significance of the Fe/O anomaly are unchanged. The current error budget may overstate the precision of the abundance determinations.
  3. [§4, Figure 4] The Fe/O–age evolutionary tracks of Isobe et al. (2022) are used to argue that BrHNe and/or PISNe are required to explain the data. However, the comparison is only presented for the adopted Izotov ICF. Given that the Rodríguez & Rubin ICF shifts both data points downward by ~0.25 dex, the visual separation from the 'No HN/PISN' track may shrink significantly. Without re-plotting the tracks, it is unclear whether HSCJ1631+4426 would still lie above the no-hypernova track at the 1σ level after applying the alternate ICF and the atomic-data spread. The paper should show the model comparison under both ICF choices, or at least state quantitatively the minimum distance (in dex) between each data point and the 'No HN/PISN' track after all systematics are combined. This is load-bearing for the specific BrHNe/PISNe attribution.
minor comments (5)
  1. [Abstract, §5] The phrase 'approach or exceed solar' is used without qualification. Consider adding 'under the adopted Izotov et al. (2006) ICF' or reporting the alternative-ICF values in the abstract to avoid overstatement.
  2. [§2] The negative E(B-V) for SDSSJ0811+4730 is clipped to zero. Please state explicitly that this clipping does not affect the line ratios used in the abundance analysis (or justify with a short test).
  3. [Table 1] The identical uncertainty (0.11) for all lines in HSCJ1631 boundary 1 should be clarified in the table caption as a single RMS-derived value per spectrum, not a per-line noise estimate.
  4. [§4] The progenitor-count estimate for PISNe assumes a Chabrier IMF with a 300 M⊙ upper cutoff. The sensitivity of the resulting count (∼170) to this assumed cutoff and to the mass–metallicity relation should be stated, as this is an ad-hoc assumption in the argument.
  5. [Data Availability] The statement 'available on reasonable request' is restrictive; consider depositing the reduced data cubes in a public archive (e.g., Keck Observatory Archive) to facilitate reproducibility, given the paper's emphasis on independent checks.

Circularity Check

0 steps flagged

No significant circularity: the Fe/O measurements come from direct KCWI line measurements with a literature ICF, and the model comparison is an external theoretical overlay, not a fit to the data.

full rationale

The empirical chain is self-contained: emission-line fluxes are measured from the KCWI datacubes, electron temperatures and ionic abundances are derived with PyNeb, and O/H and Fe2+/H+ follow from standard direct-method formulae with no parameter fitted to the target quantities. Total Fe/H is obtained by applying the Izotov et al. (2006) ICF, which is an external literature calibration, not an input fitted to these galaxies. The paper explicitly reports the alternative Rodríguez & Rubin (2005) ICF, which lowers log(Fe/O) by 0.23–0.27 dex, and it states the systematic caveat that the ICF 'was calibrated under standard star-forming conditions' and that harder ionising radiation 'could in principle affect the iron ICF more than other abundance ratios.' Even at the lower values the Fe/O ratios sit above the CCSN-only tracks, so the central anomaly is not an artifact of the ICF choice. The interpretation involving BrHNe/PISNe is made by comparing the new data to Fe/O-age tracks 'adapted from Isobe et al. (2022)', whose lead author is a co-author of this paper; this is a self-citation but not a circular reduction, because the tracks are theoretical chemical-evolution model pathways with stated channel assumptions rather than fits to the present data points. The paper also cites Isobe et al. (2022) for the exclusion of SNe Ia, but the age argument is independently supported by the young ages quoted from Kojima et al. (2020) and Izotov et al. (2018) and by the new EW0(Hβ) estimates. No equation or fitted parameter in this paper reduces by construction to the reported Fe/O values or to the BrHNe/PISNe conclusion.

Axiom & Free-Parameter Ledger

3 free parameters · 7 axioms · 0 invented entities

The line fluxes are the measured core of the paper; everything else is a conversion chain. The largest numerical lever is the iron ICF (~7-17x), which is not measured from these data and carries an estimated 0.2-0.3 dex systematic. The second lever is the empirical Te([OII]) relation. The interpretive conclusion additionally leans on author-built model tracks (Isobe et al. 2022) and a chosen IMF shape for the PISN counting argument. No new physical entities are introduced.

free parameters (3)
  • Iron ionization correction factor (ICF), Izotov et al. (2006) = ≈7.4 (HSCJ1631+4426), ≈17.2 (SDSSJ0811+4730)
    Multiplies the directly observed Fe2+/H+ to obtain total Fe/H; 80-94% of the iron is unobserved Fe3+. The alternative Rodriguez & Rubin (2005) ICF shifts log(Fe/O) by -0.23 to -0.27 dex. Adopted from literature calibrated on standard conditions; the dominant numerical determinant of the Fe/O values.
  • Te([OII]) empirical relation slope/intercept = 0.7, 3000 K
    Te([OII]) = 0.7 Te([OIII]) + 3000 K (Campbell et al. 1986; Garnett 1992). Sets the O+ and Fe2+ zone temperatures used in the ionic abundances; adopted, not fitted to these data.
  • E(B-V) clipping for SDSSJ0811+4730 = 0.0 (fitted value was -0.084)
    Negative extinction clipped to zero, standard practice; corrections are ≤7% so the impact on the result is minor.
axioms (7)
  • domain assumption Case B recombination values and the Cardelli et al. (1989) extinction law govern the Balmer-decrement dust correction
    Section 2: E(B-V) fitted by least-squares over Balmer lines relative to theoretical Case B (Osterbrock 1989); the resulting corrections are small (≤7%) but the assumption enters all line ratios.
  • domain assumption O/H = O+/H+ + O2+/H+ (negligible O3+)
    Section 3: total oxygen is the sum of two ionic abundances; standard for Te ~ 2e4 K but O3+ is not directly measured.
  • domain assumption [FeIII] lambda4658 is unblended and sufficient as the sole Fe2+ diagnostic
    Section 3 and Table 1: total iron rests on this single line; the paper tests six PyNeb atomic datasets (0.10-0.13 dex spread) but cannot exclude an unidentified blend; CIV 4659 contamination is ruled out only by citing Kojima et al. (2021).
  • domain assumption The Izotov et al. (2006) ICF converts Fe2+/H+ to Fe/H under these hard-radiation conditions
    Sections 3-4: the factor is ~7.4-17.2, so 80-94% of the iron is attributed to unobserved Fe3+; the paper itself notes the ICF 'was calibrated under standard star-forming conditions.'
  • domain assumption The galaxies are young (3.3-50 Myr), excluding SNe Ia iron enrichment
    Section 4: ages from Izotov et al. (2018) and Kojima et al. (2020), plus pyStarburst99 EW0(H-beta) estimates of 2.8-4.1 Myr; ages are adopted from the literature, not measured here.
  • domain assumption The Isobe et al. (2022) model tracks (including a 20% BrHN fraction) adequately represent enrichment pathways
    Figure 4: the tracks determine that PISNe/BrHNe are 'required'; the 20% BrHN proportion is a model input, and the model's lead author is a co-author who previously concluded these same objects need PISNe/BrHNe.
  • ad hoc to paper Chabrier IMF with 300 solar-mass upper cutoff used for the PISN progenitor-count argument
    Section 4: 'stars above 140 Msun constitute ~0.01% of all stars, such that a 1e6 Msun burst is expected to produce ~170 such progenitors'; the IMF cutoff and burst mass are chosen to make PISNe statistically plausible and are not otherwise constrained.

pith-pipeline@v1.3.0-alltime-deepseek · 13045 in / 31221 out tokens · 250270 ms · 2026-08-02T01:09:07.290868+00:00 · methodology

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read the original abstract

We present integral field spectroscopic observations of two local extremely metal-poor galaxies (XMPs), HSCJ1631+4426 and SDSSJ0811+4730, obtained with the Keck Cosmic Web Imager (KCWI) over the wavelength range $3545-5529$ {\AA} at a spectral sampling of 0.5 {\AA}, capturing bright nebular emission lines essential for determining gas-phase metallicity and chemical enrichment measurements. Using integrated spectra, we derive oxygen abundances of $\rm12+\log(O/H)=7.079\pm0.010$ and $6.926\pm0.004$, and elevated Fe/O ratios of $\rm\log(Fe/O)=-1.57\pm0.17$ and $-1.28\pm0.07$, for HSCJ1631+4426 and SDSSJ0811+4730 respectively. Each galaxy is fully contained within the $\sim$8'' field of view, with 0.15'' spaxels providing spatially resolved information. These measurements indicate unusually efficient iron enhancement at extremely low metallicity; Fe/O ratios approach or exceed solar despite oxygen abundances of only $\sim$2% solar, inconsistent with enrichment from core-collapse supernovae alone or delayed Type Ia supernovae given the young ages of the systems. Comparison with chemical evolution models suggests rare, highly energetic explosions such as bright hypernovae and/or pair-instability supernovae are likely responsible. Our results reinforce the growing evidence that XMPs can reflect the nucleosynthetic processes of early energetic stellar explosions, serving as local laboratories for chemical enrichment pathways prevalent in the early Universe.

Figures

Figures reproduced from arXiv: 2607.14758 by Aaron Myszka, Brent Groves, Chiaki Kobayashi, Haruka Kusakabe, Jarle Brinchmann, Karl Glazebrook, Michael V. Maseda, Nikole M. Nielsen, Sarah M. Sweet, Themiya Nanayakkara, Yuki Isobe.

Figure 1
Figure 1. Figure 1: Composite RGB images of (a) HSCJ1631+4426 and (b) SDSSJ0811+4730. Each image is constructed from the fitted line fluxes of [Oiii] 𝜆5007 (red), H𝛽 (green), and the combined [Oii] 𝜆3726 + 𝜆3729 dou￾blet (blue). Galaxy boundaries identified using astrodendro are overlaid in white, with the individual boundaries numbered for reference. A PSF circle and 3-arcsecond scale bar are shown bottom right. An inset is … view at source ↗
Figure 2
Figure 2. Figure 2: The rest-frame integrated spectra of a) the primary boundary of HSCJ1631+4426, b) the secondary boundary of HSCJ1631+4426, and c) SDSSJ0811+4730. Spectra are extracted within boundaries shown in [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: shows the positions of the two XMP galaxies in metallicity-log(Fe/O) space, highlighting their anomalously high iron enrichment. Kojima et al. (2021) investigate whether the elevated log(Fe/O) ratios could be artificially inflated by hard extreme-ultraviolet radia￾tion, shock heating, or contamination from Civ 𝜆4659, and rule out each of these effects as a dominant contributor. The authors also find that t… view at source ↗
Figure 4
Figure 4. Figure 4: Fe/O-age evolutionary tracks, adapted from Isobe et al. (2022), with our results for HSCJ1631+4426 and SDSSJ0811+4730 overlaid. Solid lines indicate theoretical chemical evolution model pathways (Isobe et al. 2022) for a 20% proportion of bright hypernovae (BrHN 20%), pair-instability supernovae (PISN), entirely hypernovae (HN), or no hypernovae/PISNe (No HN/PISN). Dashed lines show the Milky Way Fe/O mode… view at source ↗

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Works this paper leans on

59 extracted references · 1 canonical work pages

  1. [1]

    , keywords =

    Exploring the chemical content of Galaxies using the SAMI Zoom Survey: a data release of 92 spatially resolved H II regions in nearby galaxies. , keywords =. doi:10.1093/mnras/staf742 , adsurl =

    work page doi:10.1093/mnras/staf742

  2. [2]

    2015 , keywords =

    Astronomy and Astrophysics , author =. 2015 , keywords =. doi:10.1051/0004-6361/201323152 , urldate =

    doi:10.1051/0004-6361/201323152 2015

  3. [3]

    , keywords =

    The MUSE Hubble Ultra Deep Field surveys: Data release II. , keywords =. doi:10.1051/0004-6361/202244187 , archivePrefix =. 2211.08493 , primaryClass =

    Pith/arXiv arXiv

  4. [4]

    doi:10.5281/zenodo.11813 , version =

    LMFIT: Non-Linear Least-Square Minimization and Curve-Fitting for Python. doi:10.5281/zenodo.11813 , version =

    doi:10.5281/zenodo.11813

  5. [6]

    EMPRESS. III. Morphology, Stellar Population, and Dynamics of Extremely Metal-poor Galaxies (EMPGs): Are EMPGs Local Analogs of High-z Young Galaxies?. , keywords =. doi:10.3847/1538-4357/ac05bf , archivePrefix =. 2004.11444 , primaryClass =

    Pith/arXiv arXiv 2004

  6. [7]

    EMPRESS. IV. Extremely Metal-poor Galaxies Including Very Low-mass Primordial Systems with M _ * = 10 ^ 4 - 10 ^ 5 M _ and 2\\. , keywords =. doi:10.3847/1538-4357/ac3509 , archivePrefix =. 2108.03850 , primaryClass =

    Pith/arXiv arXiv

  7. [8]

    , keywords =

    The chemical composition of metal-poor emission-line galaxies in the Data Release 3 of the Sloan Digital Sky Survey. , keywords =. doi:10.1051/0004-6361:20053763 , archivePrefix =. astro-ph/0511644 , primaryClass =

    Pith/arXiv arXiv

  8. [9]

    Extremely Metal-poor Representatives Explored by the Subaru Survey (EMPRESS). I. A Successful Machine-learning Selection of Metal-poor Galaxies and the Discovery of a Galaxy with M* < 10 ^ 6 M _ and 0.016 Z _. , keywords =. doi:10.3847/1538-4357/aba047 , archivePrefix =. 1910.08559 , primaryClass =

    arXiv 1910

  9. [10]

    EMPRESS. II. Highly Fe-enriched Metal-poor Galaxies with 1.0 (Fe/O) _ and 0.02 (O/H) _ : Possible Traces of Supermassive (>300 M _ ) Stars in Early Galaxies. , keywords =. doi:10.3847/1538-4357/abec3d , archivePrefix =. 2006.03831 , primaryClass =

    arXiv 2006

  10. [11]

    , keywords =

    J0811+4730: the most metal-poor star-forming dwarf galaxy known. , keywords =. doi:10.1093/mnras/stx2478 , archivePrefix =. 1709.00202 , primaryClass =

    Pith/arXiv arXiv

  11. [12]

    , keywords =

    The Nucleosynthetic Signature of Population III. , keywords =. doi:10.1086/338487 , archivePrefix =. astro-ph/0107037 , primaryClass =

    Pith/arXiv arXiv

  12. [13]

    , keywords =

    How Much ^ 56 Ni Can Be Produced in Core-Collapse Supernovae? Evolution and Explosions of 30-100 M _ Stars. , keywords =. doi:10.1086/524767 , archivePrefix =. 0707.2598 , primaryClass =

    Pith/arXiv arXiv

  13. [14]

    , keywords =

    Host Galaxies of Type Ic and Broad-lined Type Ic Supernovae from the Palomar Transient Factory: Implications for Jet Production. , keywords =. doi:10.3847/1538-4357/ab4185 , archivePrefix =. 1901.00872 , primaryClass =

    Pith/arXiv arXiv 1901

  14. [15]

    , keywords =

    Constraining the Final Fates of Massive Stars by Oxygen and Iron Enrichment History in the Galaxy. , keywords =. doi:10.3847/1538-4357/aaa024 , archivePrefix =. 1712.02013 , primaryClass =

    Pith/arXiv arXiv

  15. [16]

    High signal-to-noise optical spectroscopy

    The stellar populations and evolution of H II galaxies - I. High signal-to-noise optical spectroscopy. , keywords =. doi:10.1093/mnras/223.4.811 , adsurl =

    doi:10.1093/mnras/223.4.811

  16. [17]

    , keywords =

    Electron Temperature Variations and the Measurement of Nebular Abundances. , keywords =. doi:10.1086/116146 , adsurl =

    doi:10.1086/116146

  17. [18]

    A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood

    Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood. , keywords =. doi:10.1051/0004-6361/201322631 , archivePrefix =. 1309.2631 , primaryClass =

    Pith/arXiv arXiv

  18. [19]

    , keywords =

    First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy. , keywords =. doi:10.1051/0004-6361:20034074 , archivePrefix =. astro-ph/0311082 , primaryClass =

    Pith/arXiv arXiv

  19. [20]

    Abundances for metal-poor stars with accurate parallaxes. I. Basic data. , keywords =. doi:10.1051/0004-6361:20030439 , archivePrefix =. astro-ph/0303653 , primaryClass =

    Pith/arXiv arXiv

  20. [21]

    , year = 1993, month = aug, volume =

    The Chemical Evolution of the Galactic Disk - Part One - Analysis and Results. , year = 1993, month = aug, volume =

    1993

  21. [22]

    , keywords =

    The chemical compositions of Galactic disc F and G dwarfs. , keywords =. doi:10.1046/j.1365-8711.2003.06305.x , archivePrefix =. astro-ph/0211551 , primaryClass =

    arXiv 2003

  22. [23]

    Astrophysics Source Code Library , author =

    astrodendro:. Astrophysics Source Code Library , author =. 2019 , keywords =

    2019

  23. [24]

    , year = 2013, month = aug, volume =

    Nucleosynthesis in Stars and the Chemical Enrichment of Galaxies. , year = 2013, month = aug, volume =. doi:10.1146/annurev-astro-082812-140956 , adsurl =

    doi:10.1146/annurev-astro-082812-140956 2013

  24. [25]

    The Evolution and Explosion of Massive Stars. II. Explosive Hydrodynamics and Nucleosynthesis. , keywords =. doi:10.1086/192237 , adsurl =

    doi:10.1086/192237

  25. [26]

    , keywords =

    The [Fe IV] Discrepancy: Constraining the Iron Abundances in Nebulae. , keywords =. doi:10.1086/429958 , archivePrefix =. astro-ph/0504131 , primaryClass =

    Pith/arXiv arXiv

  26. [27]

    , keywords =

    The origin and chemical evolution of carbon in the Galactic thin and thick discs ^ *. , keywords =. doi:10.1111/j.1365-2966.2006.10037.x , archivePrefix =. astro-ph/0601130 , primaryClass =

    arXiv 2006

  27. [28]

    , keywords =

    The chemical make-up of the Sun: A 2020 vision. , keywords =. doi:10.1051/0004-6361/202140445 , archivePrefix =. 2105.01661 , primaryClass =

    Pith/arXiv arXiv 2020

  28. [29]

    , year = 1967, month = jun, volume =

    Instabilities in Highly Evolved Stellar Models. , year = 1967, month = jun, volume =. doi:10.1086/149204 , adsurl =

    doi:10.1086/149204 1967

  29. [30]

    , keywords =

    A complex multiphase DLA associated with a compact group at z = 2.431 traces accretion, outflows, and tidal streams. , keywords =. doi:10.1093/mnras/stac1824 , archivePrefix =. 2206.12501 , primaryClass =

    Pith/arXiv arXiv

  30. [31]

    , keywords =

    Optical spectroscopy of the extremely metal-deficient star-forming galaxy HSC J1631+4426: a test of the strong-line method. , keywords =. doi:10.1093/mnrasl/slac095 , archivePrefix =. 2208.08766 , primaryClass =

    Pith/arXiv arXiv

  31. [32]

    , keywords =

    The Chemical Composition of the Sun. , keywords =. doi:10.1146/annurev.astro.46.060407.145222 , archivePrefix =. 0909.0948 , primaryClass =

    arXiv

  32. [33]

    , keywords =

    Reconciling the Stellar and Nebular Spectra of High-redshift Galaxies. , keywords =. doi:10.3847/0004-637X/826/2/159 , archivePrefix =. 1605.07186 , primaryClass =

    Pith/arXiv arXiv

  33. [34]

    Nature Astronomy , keywords =

    Evidence for the accretion origin of halo stars with an extreme r-process enhancement. Nature Astronomy , keywords =. doi:10.1038/s41550-019-0764-5 , archivePrefix =. 1905.04141 , primaryClass =

    Pith/arXiv arXiv 1905

  34. [35]

    , keywords =

    Observational Clues to the Progenitors of Type Ia Supernovae. , keywords =. doi:10.1146/annurev-astro-082812-141031 , archivePrefix =. 1312.0628 , primaryClass =

    Pith/arXiv arXiv

  35. [36]

    , keywords =

    Hunting for extremely metal-poor emission-line galaxies in the Sloan Digital Sky Survey: MMT and 3.5 m APO observations. , keywords =. doi:10.1051/0004-6361/201219733 , archivePrefix =. 1207.5971 , primaryClass =

    Pith/arXiv arXiv

  36. [37]

    , keywords =

    The evolution of isotope ratios in the Milky Way Galaxy. , keywords =. doi:10.1111/j.1365-2966.2011.18621.x , archivePrefix =. 1102.5312 , primaryClass =

    arXiv 2011

  37. [38]

    , keywords =

    Gas accretion as the origin of chemical abundance gradients in distant galaxies. , keywords =. doi:10.1038/nature09451 , archivePrefix =. 1010.2534 , primaryClass =

    Pith/arXiv arXiv

  38. [39]

    , keywords =

    The Origin of Elements from Carbon to Uranium. , keywords =. doi:10.3847/1538-4357/abae65 , archivePrefix =. 2008.04660 , primaryClass =

    Pith/arXiv arXiv 2008

  39. [40]

    EMPRESS. XIII. Chemical Enrichment of Young Galaxies Near and Far at z 0 and 4─10: Fe/O, Ar/O, S/O, and N/O Measurements with a Comparison of Chemical Evolution Models. , keywords =. doi:10.3847/1538-4357/ad13ff , archivePrefix =. 2305.02078 , primaryClass =

    Pith/arXiv arXiv

  40. [41]

    , keywords =

    GA-NIFS: an extremely nitrogen-loud and chemically stratified galaxy at z 5.55. , keywords =. doi:10.1093/mnras/stae2375 , archivePrefix =. 2404.04148 , primaryClass =

    Pith/arXiv arXiv

  41. [42]

    , keywords =

    Resolving the nature and putative nebular emission of GS9422: an obscured AGN without exotic stars. , keywords =. doi:10.1093/mnras/staf718 , archivePrefix =. 2404.02194 , primaryClass =

    Pith/arXiv arXiv

  42. [43]

    , keywords =

    Low [O/Fe] Ratio in a Luminous Galaxy at the Early Cosmic Epoch (z > 10): Signature of Short Delay Time or Bright Hypernovae/Pair-instability Supernovae?. , keywords =. doi:10.3847/1538-4357/ad84e8 , archivePrefix =. 2407.14470 , primaryClass =

    Pith/arXiv arXiv

  43. [44]

    , keywords =

    Fe Abundances of Early Galaxies at z = 9─12 Derived with Deep JWST Spectra. , keywords =. doi:10.3847/1538-4357/ae04e6 , archivePrefix =. 2503.11457 , primaryClass =

    Pith/arXiv arXiv

  44. [45]

    , keywords =

    JADES: nitrogen enhancement in high-redshift broad-line active galactic nuclei. , keywords =. doi:10.1093/mnrasl/slaf056 , archivePrefix =. 2502.12091 , primaryClass =

    Pith/arXiv arXiv

  45. [46]

    , keywords =

    Subaru/FOCAS IFU revealed the metallicity gradient of a local extremely metal-poor galaxy. , keywords =. doi:10.1093/pasj/psab100 , archivePrefix =. 2110.05030 , primaryClass =

    Pith/arXiv arXiv

  46. [47]

    , keywords =

    The Relationship between Infrared, Optical, and Ultraviolet Extinction. , keywords =. doi:10.1086/167900 , adsurl =

    doi:10.1086/167900

  47. [48]

    Astrophysics of gaseous nebulae and active galactic nuclei

  48. [49]

    , keywords =

    pySTARBURST99: The Next Generation of STARBURST99. , keywords =. doi:10.3847/1538-4365/adddb6 , archivePrefix =. 2505.24841 , primaryClass =

    Pith/arXiv arXiv

  49. [50]

    , keywords =

    Electron-impact Excitation of Fe ^ 2 + : A Comparison of Intermediate Coupling Frame Transformation, Breit-Pauli and Dirac R-matrix Calculations. , keywords =. doi:10.1088/0004-637X/785/2/99 , archivePrefix =. 1402.4743 , primaryClass =

    Pith/arXiv arXiv

  50. [51]

    Atoms , keywords =

    Atomic Data Assessment with PyNeb: Radiative and Electron Impact Excitation Rates for [Fe II] and [Fe III]. Atoms , keywords =. doi:10.3390/atoms11040063 , archivePrefix =. 2304.01298 , primaryClass =

    Pith/arXiv arXiv

  51. [52]

    Atomic Data and Nuclear Data Tables , year = 2009, month = mar, volume =

    Weighted f-values, A-values, and line strengths for the E1 transitions among 3d ^ 6 , 3d ^ 5 4s, and 3d ^ 5 4p levels of Fe III. Atomic Data and Nuclear Data Tables , year = 2009, month = mar, volume =. doi:10.1016/j.adt.2008.12.001 , adsurl =

    doi:10.1016/j.adt.2008.12.001 2009

  52. [53]

    Atomic data from the Iron Project. XVII. Radiative transition probabilities for dipole allowed and forbidden transitions in Fe III. , keywords =

  53. [54]

    , keywords =

    Transition probabilities for forbidden lines of Fe III. , keywords =

  54. [55]

    , keywords =

    New forbidden and fluorescent Fe III lines identified in HST spectra of eta Carinae. , keywords =

  55. [56]

    , keywords =

    The NIRVANDELS survey: the stellar and gas-phase mass-metallicity relations of star-forming galaxies at z = 3.5. , keywords =. doi:10.1093/mnras/stae1705 , archivePrefix =. 2405.00774 , primaryClass =

    Pith/arXiv arXiv

  56. [57]

    , keywords =

    The VANDELS survey: the stellar metallicities of star-forming galaxies at 2.5 < z < 5.0. , keywords =. doi:10.1093/mnras/stz1402 , archivePrefix =. 1903.11081 , primaryClass =

    Pith/arXiv arXiv 1903

  57. [58]

    , keywords =

    The Stellar Mass versus Stellar Metallicity Relation of Star-forming Galaxies at 1.6 z 3.0 and Implications for the Evolution of the -enhancement. , keywords =. doi:10.3847/1538-4357/ac399e , archivePrefix =. 2109.06044 , primaryClass =

    Pith/arXiv arXiv

  58. [59]

    , keywords =

    JADES: the chemical enrichment pattern of distant galaxies ─ enhancement, silicon depletion, and iron enhancement. , keywords =. doi:10.1093/mnras/stag123 , archivePrefix =. 2509.18055 , primaryClass =

    arXiv

  59. [60]

    , keywords =

    Galactic Stellar and Substellar Initial Mass Function. , keywords =. doi:10.1086/376392 , archivePrefix =. astro-ph/0304382 , primaryClass =

    Pith/arXiv arXiv