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arxiv: 2606.17153 · v1 · pith:ELV4TLNYnew · submitted 2026-06-15 · 🌌 astro-ph.GA

Chemical hints of Population III stars from silicon abundances in massive galaxies

E. Eftekhari , A. Ferr\'e-Mateu , A. Vazdekis , F. La Barbera , M. A. Beasley , J. P. V. Benedetti , M. Kriek This is my paper

Pith reviewed 2026-06-27 03:04 UTC · model grok-4.3

classification 🌌 astro-ph.GA
keywords silicon abundancerelic galaxyNGC 1277pair-instability supernovaechemical evolutionPopulation IIImagnesium abundanceearly star formation
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The pith

Elevated silicon-to-magnesium ratio in NGC 1277 indicates enrichment from pair-instability supernovae.

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

The study analyzes deep near-infrared spectra of the massive relic galaxy NGC 1277 to measure its chemical abundances. It reports a silicon-to-magnesium ratio significantly higher than what standard stellar population models or core-collapse supernova yields can produce. This discrepancy points to nucleosynthesis from pair-instability supernovae associated with extremely massive, metal-poor stars. Such stars would have been common in the earliest phases of galaxy formation. Because NGC 1277 formed quickly at high redshift and evolved passively, it preserves this early chemical imprint with little dilution from later events.

Core claim

Using deep near-infrared spectroscopy of NGC 1277, the authors measure [Si/Fe]=1.05^{+0.45}_{-0.27} and [Mg/Fe]=0.36^{+0.27}_{-0.24}, resulting in [Si/Mg]=0.67^{+0.45}_{-0.27}. This ratio exceeds predictions from current models and typical core-collapse supernova yields. The enhancement is attributed to contributions from pair-instability supernovae or similar channels linked to very massive stars. The rapid formation of this relic galaxy allows these signatures to persist undiluted.

What carries the argument

The [Si/Mg] abundance ratio measured via silicon absorption features in the near-infrared spectrum of NGC 1277, used as a tracer for the nucleosynthetic yields of pair-instability supernovae.

If this is right

  • Massive relic galaxies can retain chemical evidence of the first generations of stars.
  • Pair-instability supernovae played a role in the chemical enrichment of the early universe.
  • Current supernova yield models require updates to account for extremely massive star contributions.
  • Similar chemical anomalies may be found in other compact high-redshift formed galaxies.
  • JWST data on early galaxies could be interpreted in light of these local constraints.

Where Pith is reading between the lines

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

  • Confirmation in more galaxies would strengthen the case for Population III star contributions to massive galaxy formation.
  • This approach could be applied to other abundance ratios to probe different aspects of early nucleosynthesis.
  • It raises the possibility that the initial mass function in high-redshift star formation was top-heavy.
  • Future observations might detect direct signatures in high-redshift systems.

Load-bearing premise

The observed abundance ratio truly reflects the nucleosynthetic output of the galaxy's stars rather than resulting from inaccuracies in the spectral analysis or supernova yield predictions.

What would settle it

Reproducing the measured [Si/Mg] ratio using updated stellar population models that include only standard core-collapse supernovae without pair-instability contributions would falsify the claim.

Figures

Figures reproduced from arXiv: 2606.17153 by A. Ferr\'e-Mateu, A. Vazdekis, E. Eftekhari, F. La Barbera, J. P. V. Benedetti, M. A. Beasley, M. Kriek.

Figure 1
Figure 1. Figure 1: NIR Mg and Si absorption line strengths in NGC 1277 and massive ETGs. Top: Zoomed-in view of the spectra of NGC 1277 (pink line) and the stacked massive ETGs (cyan) around the MgI1.18, SiI1.20, and SiI1.59 features, with their corresponding error spectra. Yellow bands highlight these key absorption features, and light blue regions show the pseudo-continuum bands used for their index measurements. As refere… view at source ↗
Figure 2
Figure 2. Figure 2: [Si/Mg] as a function of SN progenitor mass.The measured [Si/Mg] abundance ratios are compared to theoretical nucleosynthetic yields from SN models across a range of progenitor masses. Circles, squares, and diamonds denote the predicted yields for CCSNe, HNe, and PISNe, respectively, based on Nomoto et al. (2013). The shaded bands represent the 68% credible intervals of the inferred [Si/Mg] ratios for NGC … view at source ↗
Figure 3
Figure 3. Figure 3: Schematic illustration of early chemical enrichment and galaxy evolution under the two-phase formation scenario. In the early Universe (top left), metal-free stars, including both massive Pop III stars (large stars) and less massive ones (smaller stars), form from pristine gas. Pop III stars end as PISNe (orange bursts), while lower-mass metal-free stars produce CCSNe (blue bursts). The stars that form fro… view at source ↗
read the original abstract

The formation of massive galaxies remains a fundamental question in astrophysics, with recent JWST observations suggesting that intense star formation occurred earlier than previously expected. We used the prototypical massive relic galaxy NGC 1277 as a fossil record to probe the chemical signatures of early star formation. With a stellar mass of $1.2 \pm 0.4 \times 10^{11}M_\odot$ and a compact structure (half-light radius of 1.2 kpc), NGC 1277 is representative of massive relic galaxies-systems that formed rapidly at high redshifts ("red nuggets" at $z>2$) and have since undergone largely passive evolution, preserving the imprint of their earliest stellar populations. Using deep near-infrared spectroscopy, we identified unusually strong silicon (Si) absorption features in this galaxy. We measure $[\mathrm{Si}/\mathrm{Fe}]=1.05^{+0.45}_{-0.27}$ and $[\mathrm{Mg}/\mathrm{Fe}]=0.36^{+0.27}_{-0.24}$, corresponding to a significantly enhanced silicon-to-magnesium ratio ($[\mathrm{Si}/\mathrm{Mg}]=0.67^{+0.45}_{-0.27}$) which cannot be reproduced by current stellar population models or typical core-collapse supernova yields. This enhancement suggests a contribution from very massive, metal-poor progenitors during the earliest phases of star formation. Such conditions are consistent with nucleosynthetic yields from pair-instability supernovae or other enrichment channels associated with extremely massive stars, whose chemical signatures are expected to remain less diluted in systems like NGC 1277 due to their rapid formation timescales and minimal late-time accretion. This result provides rare chemical evidence of early massive-star enrichment preserved in a local relic galaxy and opens a new observational window into the chemical evolution of the Universe.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reports deep near-infrared spectroscopy of the massive relic galaxy NGC 1277, deriving [Si/Fe] = 1.05^{+0.45}_{-0.27}, [Mg/Fe] = 0.36^{+0.27}_{-0.24} and thus [Si/Mg] = 0.67^{+0.45}_{-0.27}. The authors argue that this elevated silicon-to-magnesium ratio lies outside the range produced by standard stellar population synthesis models and typical core-collapse supernova yields, and interpret it as evidence for an early contribution from pair-instability supernovae or other channels associated with extremely massive, metal-poor stars whose signatures are preserved in this rapidly formed, passively evolving system.

Significance. If the abundance ratio and its discrepancy with existing yields are robust, the result supplies rare local chemical evidence for very massive star enrichment at high redshift, complementing JWST observations of early intense star formation. The choice of a compact relic galaxy as a fossil record is a clear methodological strength, as is the falsifiable nature of the claimed mismatch with standard yields.

major comments (2)
  1. [Methods (spectral analysis)] The central claim that the observed [Si/Mg] cannot be reproduced by current models rests on the spectral fitting and yield comparison; the abstract supplies no quantitative details on the fitting procedure, line list, or specific supernova yield grids employed, so the manuscript must demonstrate in the methods section that the ratio remains discrepant after systematic tests (e.g., alternative stellar libraries or continuum placement).
  2. [Discussion (final paragraph)] The interpretation that the enhancement is undiluted relies on NGC 1277 having experienced minimal late-time accretion; this assumption is load-bearing for the Population III / PISN conclusion and should be supported by explicit comparison to chemical-evolution models that include varying accretion histories.
minor comments (2)
  1. Error bars on the abundance ratios are asymmetric; ensure that all figures and tables report them consistently and that the text clarifies how they were derived from the spectral fits.
  2. [Abstract] The notation [Si/Mg] is used without explicit definition in the abstract; add a brief parenthetical reminder of the solar reference scale for clarity.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their positive assessment and constructive comments, which have helped us improve the manuscript. We address each major comment below.

read point-by-point responses

  1. Referee: [Methods (spectral analysis)] The central claim that the observed [Si/Mg] cannot be reproduced by current models rests on the spectral fitting and yield comparison; the abstract supplies no quantitative details on the fitting procedure, line list, or specific supernova yield grids employed, so the manuscript must demonstrate in the methods section that the ratio remains discrepant after systematic tests (e.g., alternative stellar libraries or continuum placement).

    Authors: We agree that additional quantitative details and robustness tests will strengthen the presentation. The full manuscript contains a Methods section on the spectral fitting, but we will expand it to include explicit descriptions of the fitting procedure, line list, supernova yield grids employed, and results from systematic tests using alternative stellar libraries and continuum placements. These tests show that the [Si/Mg] discrepancy persists. revision: yes

  2. Referee: [Discussion (final paragraph)] The interpretation that the enhancement is undiluted relies on NGC 1277 having experienced minimal late-time accretion; this assumption is load-bearing for the Population III / PISN conclusion and should be supported by explicit comparison to chemical-evolution models that include varying accretion histories.

    Authors: The manuscript already highlights NGC 1277's rapid formation at high redshift and subsequent passive evolution as evidence for limited late-time accretion. To further support this, we will add explicit comparisons to chemical-evolution models with varying accretion histories in the revised Discussion, demonstrating consistency with the observed undiluted enhancement. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper derives [Si/Mg] from direct spectroscopic measurements of absorption features in NGC 1277 and compares the value to independent external grids of stellar population synthesis models and core-collapse supernova yield tables. No step in the provided text defines a quantity in terms of itself, renames a fitted parameter as a prediction, or relies on a load-bearing self-citation whose content reduces to the present result. The discrepancy claim is therefore falsifiable against external benchmarks and does not reduce to the paper's own inputs by construction.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim depends on the completeness of existing stellar population and supernova yield models; the abundance ratios themselves are derived quantities whose extraction involves multiple fitting choices not detailed here.

free parameters (1)
  • spectral fitting parameters
    Abundance ratios are extracted via model fitting whose exact parameters and priors are not listed.
axioms (1)
  • domain assumption Current stellar population synthesis models and core-collapse supernova yield tables are sufficiently complete that a mismatch indicates new physics rather than model incompleteness.
    Invoked when stating the observed ratio cannot be reproduced.

pith-pipeline@v0.9.1-grok · 5901 in / 1324 out tokens · 61752 ms · 2026-06-27T03:04:38.756124+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

300 extracted references · 194 canonical work pages · 91 internal anchors

  1. [1]

    , keywords =

    Calibration of metallicity effects on the integrated colors of globular clusters and early-type galaxies. , keywords =. doi:10.1086/156315 , adsurl =

    work page doi:10.1086/156315

  2. [2]

    , keywords =

    An atlas of stellar spectra between 2.00 and 2.45 mu.m. , keywords =. doi:10.1093/mnras/237.2.495 , adsurl =

    work page doi:10.1093/mnras/237.2.495

  3. [3]

    The Astrophysical Journal , volume=

    A simple void-searching algorithm , author=. The Astrophysical Journal , volume=. 1998 , publisher=

    1998

  4. [4]

    , volume=

    Ram pressure stripping of spiral galaxies in clusters , author=. , volume=. 1999 , publisher=

    1999

  5. [5]

    Astronomy & Astrophysics , volume=

    Spectral and photometric evolution of young stellar populations: The impact of gaseous emission at various metallicities , author=. Astronomy & Astrophysics , volume=. 2003 , publisher=

    2003

  6. [6]

    Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis , year = 2005, series =

    The Solar Chemical Composition. Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis , year = 2005, series =

    2005

  7. [7]

    J., & Scott, P

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

    work page doi:10.1146/annurev.astro.46.060407.145222

  8. [8]

    , volume=

    The seventh data release of the Sloan Digital Sky Survey , author=. , volume=. 2009 , publisher=

    2009

  9. [9]

    Monthly Notices of the Royal Astronomical Society , volume=

    Multiscale phenomenology of the cosmic web , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2010 , publisher=

    2010

  10. [10]

    , volume=

    Dark matter contraction and the stellar content of massive early-type galaxies: disfavoring “Light” initial mass functions , author=. , volume=. 2010 , publisher=

    2010

  11. [11]

    The Astrophysical Journal , volume=

    Qualitative interpretation of galaxy spectra , author=. The Astrophysical Journal , volume=. 2012 , publisher=

    2012

  12. [12]

    , volume=

    The tenth data release of the sloan digital sky survey: First spectroscopic data from the sdss-iii apache point observatory galactic evolution experiment , author=. , volume=. 2014 , publisher=

    2014

  13. [13]

    Monthly Notices of the Royal Astronomical Society , volume=

    KINETyS: constraining spatial variations of the stellar initial mass function in early-type galaxies★ , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2017 , publisher=

    2017

  14. [14]

    , archivePrefix = "arXiv", eprint =

    The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory. , archivePrefix = "arXiv", eprint =. doi:10.3847/1538-4365/aa8992 , adsurl =

    work page doi:10.3847/1538-4365/aa8992

  15. [15]

    Kinetys II: Constraints on spatial variations of the stellar initial mass function from K-band spectroscopy

    KINETyS II: Constraints on spatial variations of the stellar initial mass function from K-band spectroscopy. , keywords =. doi:10.1093/mnras/sty1242 , archivePrefix =. 1805.05964 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty1242

  16. [16]

    , keywords =

    The APOGEE Library of Infrared SSP Templates (A-LIST): High-resolution Simple Stellar Population Spectral Models in the H Band. , keywords =. doi:10.3847/1538-3881/abd7f1 , archivePrefix =. 2012.15773 , primaryClass =

    work page doi:10.3847/1538-3881/abd7f1 2012

  17. [17]

    , year = 1973, month = jan, volume =

    The Stellar Content of Bright Galactic Nuclei. , year = 1973, month = jan, volume =

    1973

  18. [18]

    , year = 1973, month = sep, volume =

    The Strengths of Infrared CO and h, O Bands in Late-Type Stars. , year = 1973, month = sep, volume =. doi:10.1086/152341 , adsurl =

    work page doi:10.1086/152341 1973

  19. [19]

    , keywords =

    A base of star clusters for stellar population synthesis. , keywords =

  20. [20]

    III - Radial gradients in spectral features

    Color distributions in early type galaxies. III - Radial gradients in spectral features. , keywords =. doi:10.1086/115672 , adsurl =

    work page doi:10.1086/115672

  21. [21]

    , keywords =

    Metal enrichment in elliptical galaxies and globular clusters through the study of iron and H-beta spectral indices. , keywords =. doi:10.1086/116873 , adsurl =

    work page doi:10.1086/116873

  22. [22]

    , author =

    How filaments of galaxies are woven into the cosmic web. , eprint =. doi:10.1038/380603a0 , adsurl =

    work page internal anchor Pith review doi:10.1038/380603a0

  23. [23]

    The Astrophysical Journal Letters , volume=

    Cluster versus field elliptical galaxies and clues on their formation , author=. The Astrophysical Journal Letters , volume=. 1998 , publisher=

    1998

  24. [24]

    , keywords =

    Evolutionary models for solar metallicity low-mass stars: mass-magnitude relationships and color-magnitude diagrams. , keywords =

  25. [25]

    , keywords =

    Stellar populations and surface brightness fluctuations: new observations and models. , keywords =. doi:10.1046/j.1365-8711.2001.03937.x , archivePrefix =. astro-ph/0008218 , primaryClass =

    work page doi:10.1046/j.1365-8711.2001.03937.x 2001

  26. [26]

    The Metallicity of Pre-Galactic Globular Clusters: Observational consequences of the first stars

    The Metallicity of Pregalactic Globular Clusters: The Observational Consequences of the First Stars. , keywords =. doi:10.1086/379531 , archivePrefix =. astro-ph/0309198 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/379531

  27. [27]

    Monthly Notices of the Royal Astronomical Society , volume=

    Stellar population synthesis at the resolution of 2003 , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2003 , publisher=

    2003

  28. [28]

    The Messenger , year = 2003, month = dec, volume =

    The UVES Paranal Observatory Project: A Library of High- Resolution Spectra of Stars across the Hertzsprung-Russell Diagram. The Messenger , year = 2003, month = dec, volume =

    2003

  29. [29]

    , keywords =

    M Balogh and V Eke and C Miller and I Lewis and R Bower and W Couch and R Nichol and J Bland-Hawthorn and Baldry, I K and C Baugh and T Bridges and R Cannon and S Cole and M Colless and C Collins and N Cross and G Dalton and De Propris , R and Driver, S P and G Efstathiou and Ellis, R S and Frenk, C S and K Glazebrook and P Gomez and A Gray and E Hawkins ...

    work page doi:10.1111/j.1365-2966.2004.07453.x 2004

  30. [30]

    Monthly Notices of the Royal Astronomical Society , volume=

    Keck spectroscopy and imaging of globular clusters in the lenticular galaxy NGC 524 , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2004 , publisher=

    2004

  31. [31]

    Intermediate Element Abundances in Galaxy Clusters

    Intermediate-Element Abundances in Galaxy Clusters. , keywords =. doi:10.1086/427158 , archivePrefix =. astro-ph/0309166 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/427158

  32. [32]

    , volume=

    New York University Value-Added Galaxy Catalog: a galaxy catalog based on new public surveys , author=. , volume=. 2005 , publisher=

    2005

  33. [33]

    , volume=

    Relationship between Environment and the Broadband Optical Properties of Galaxies in the Sloan Digital Sky Survey , author=. , volume=. 2005 , publisher=

    2005

  34. [34]

    Old Globular Clusters Masquerading as Young in NGC 4365?

    Old Globular Clusters Masquerading as Young in NGC 4365?. , keywords =. doi:10.1086/429889 , archivePrefix =. astro-ph/0502467 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/429889

  35. [35]

    The Astronomical Journal , volume=

    Evolution and environment of early-type galaxies , author=. The Astronomical Journal , volume=. 2006 , publisher=

    2006

  36. [36]

    , keywords =

    Galaxy bimodality versus stellar mass and environment. , eprint =. doi:10.1111/j.1365-2966.2006.11081.x , adsurl =

    work page doi:10.1111/j.1365-2966.2006.11081.x 2006

  37. [37]

    title An accretion disc-corona model for X-ray spectra of active galactic nuclei

    A 2dF spectroscopic study of globular clusters in NGC 5128: probing the formation history of the nearest giant elliptical. , keywords =. doi:10.1111/j.1365-2966.2008.13123.x , archivePrefix =. 0803.1066 , primaryClass =

    work page doi:10.1111/j.1365-2966.2008.13123.x 2008

  38. [38]

    and Nichol, Robert C

    Bamford, Steven P. and Nichol, Robert C. and Baldry, Ivan K. and Land, Kate and Lintott, Chris J. and Schawinski, Kevin and Slosar, Anže and Szalay, Alexander S. and Thomas, Daniel and Torki, Mehri and Andreescu, Dan and Edmondson, Edward M. and Miller, Christopher J. and Murray, Phil and Raddick, M. Jordan and Vandenberg, Jan , title =. , volume =. 2009 , doi =

    2009

  39. [39]

    Annual Review of Astronomy and Astrophysics , volume=

    Physical properties and environments of nearby galaxies , author=. Annual Review of Astronomy and Astrophysics , volume=. 2009 , publisher=

    2009

  40. [40]

    , volume=

    A universal stellar initial mass function? A critical look at variations , author=. , volume=. 2010 , publisher=

    2010

  41. [41]

    2012 , publisher=

    A panchromatic view of galaxies , author=. 2012 , publisher=

    2012

  42. [42]

    Monthly Notices of the Royal Astronomical Society , volume=

    PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2012 , publisher=

    2012

  43. [43]

    , volume=

    On the occurrence of galaxy harassment , author=. , volume=. 2015 , publisher=

    2015

  44. [44]

    , archivePrefix = "arXiv", eprint =

    Star formation quenching in simulated group and cluster galaxies: when, how, and why?. , archivePrefix = "arXiv", eprint =. doi:10.1093/mnras/stu2293 , adsurl =

    work page doi:10.1093/mnras/stu2293

  45. [45]

    MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 z 2.5. I. Evolution of Structural and Dynamical Properties. , archivePrefix = "arXiv", eprint =. doi:10.3847/1538-4357/834/1/18 , adsurl =

    work page doi:10.3847/1538-4357/834/1/18

  46. [46]

    A single population of red globular clusters around the massive compact galaxy NGC 1277

    A single population of red globular clusters around the massive compact galaxy NGC 1277. , keywords =. doi:10.1038/nature25756 , archivePrefix =. 1803.04893 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1038/nature25756

  47. [47]

    Comparison of Stellar Population Model Predictions Using Optical and Infrared Spectroscopy

    Comparison of stellar population model predictions using optical and infrared spectroscopy. , keywords =. doi:10.1093/mnras/stx2502 , archivePrefix =. 1709.09300 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stx2502

  48. [48]

    , volume=

    Near-infrared luminosity-sensitive features in M dwarfs and giants, and in M31 and M32 , author=. , volume=

  49. [49]

    , keywords =

    Observations and interpretations of radial gradients of absorption features in galaxies. , keywords =. doi:10.1086/156859 , adsurl =

    work page doi:10.1086/156859

  50. [50]

    , volume=

    The dwarf star content of elliptical and lenticular galaxies , author=. , volume=

  51. [51]

    , keywords =

    Structure and evolution of low-mass stars. , keywords =

  52. [52]

    Reliable random error estimation in the measurement of line-strength indices

    Reliable random error estimation in the measurement of line-strength indices. , keywords =. doi:10.1051/aas:1998123 , archivePrefix =. astro-ph/9706116 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/aas:1998123

  53. [53]

    The stellar library and index definition , author=

    Empirical calibration of the near-infrared Ca II triplet—I. The stellar library and index definition , author=. , volume=. 2001 , publisher=

    2001

  54. [54]

    The Galactic Disk Mass Budget. I. Stellar Mass Function and Density. , keywords =. doi:10.1086/321401 , archivePrefix =. astro-ph/0107018 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/321401

  55. [55]

    Monthly Notices of the Royal Astronomical Society , volume=

    The 2df galaxy redshift survey: spectra and redshifts , author=. Monthly Notices of the Royal Astronomical Society , volume=. 2001 , publisher=

    2001

  56. [56]

    , volume=

    Near-infrared line-strengths in elliptical galaxies: evidence for initial mass function variations? , author=. , volume=. 2003 , publisher=

    2003

  57. [57]

    , volume=

    Galactic stellar and substellar initial mass function , author=. , volume=. 2003 , publisher=

    2003

  58. [58]

    , eprint =

    Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood. , keywords =. doi:10.1086/381875 , archivePrefix =. astro-ph/0312201 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/381875

  59. [59]

    C., Vacca, W

    Spextool: A Spectral Extraction Package for SpeX, a 0.8-5.5 Micron Cross-Dispersed Spectrograph. , keywords =. doi:10.1086/382907 , adsurl =

    work page doi:10.1086/382907

  60. [60]

    First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy

    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 =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20034074

  61. [61]

    On the Environmental Dependence of Cluster Galaxy Assembly Timescale

    On the Environmental Dependence of the Cluster Galaxy Assembly Timescale. , keywords =. doi:10.1086/422749 , archivePrefix =. astro-ph/0405512 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/422749

  62. [62]

    Abundances In Very Metal Poor Dwarf Stars

    Abundances In Very Metal-Poor Dwarf Stars. , keywords =. doi:10.1086/422576 , archivePrefix =. astro-ph/0405286 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/422576

  63. [63]

    Astronomy and Astrophysics , eprint =

    X-ray source overdensities in Chandra distant cluster fields: A new probe to map the cosmic tapestry?. Astronomy and Astrophysics , eprint =. doi:10.1051/0004-6361:20041534 , adsurl =

    work page doi:10.1051/0004-6361:20041534

  64. [64]

    An Infrared Spectroscopic Sequence of M, L and T Dwarfs

    An Infrared Spectroscopic Sequence of M, L, and T Dwarfs. , keywords =. doi:10.1086/428040 , archivePrefix =. astro-ph/0412313 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/428040

  65. [65]

    title The many lives of active galactic nuclei: cooling flows, black holes and the luminosities and colours of galaxies

    Semi-empirical analysis of Sloan Digital Sky Survey galaxies - I. Spectral synthesis method. , keywords =. doi:10.1111/j.1365-2966.2005.08752.x , archivePrefix =. astro-ph/0412481 , primaryClass =

    work page doi:10.1111/j.1365-2966.2005.08752.x 2005

  66. [66]

    Stellar populations of Globular Clusters in the Elliptical galaxy NGC1407

    Stellar Populations of Globular Clusters in the Elliptical Galaxy NGC 1407. , keywords =. doi:10.1086/518504 , archivePrefix =. astro-ph/0703472 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/518504

  67. [67]

    , volume=

    Where do ‘red and dead’early-type void galaxies come from? , author=. , volume=. 2008 , publisher=

    2008

  68. [68]

    Evidence for Blue Straggler Stars Rejuvenating the Integrated Spectra of Globular Clusters

    Evidence for Blue Straggler Stars Rejuvenating the Integrated Spectra of Globular Clusters. , keywords =. doi:10.1086/595748 , archivePrefix =. 0810.3902 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/595748

  69. [69]

    title An accretion disc-corona model for X-ray spectra of active galactic nuclei

    An optimized H index for disentangling stellar population ages. , archivePrefix = "arXiv", eprint =. doi:10.1111/j.1365-2966.2008.14079.x , adsurl =

    work page doi:10.1111/j.1365-2966.2008.14079.x 2008

  70. [70]

    Early-type galaxies in the near-infrared: 1.5-2.4\mum spectroscopy

    Early-type galaxies in the near-infrared: 1.5-2.4 m spectroscopy. , keywords =. doi:10.1051/0004-6361/200810506 , archivePrefix =. 0808.3573 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/200810506

  71. [71]

    , volume=

    Comparing six evolutionary population synthesis models by performing spectral synthesis for galaxies , author=. , volume=. 2010 , publisher=

    2010

  72. [72]

    , volume=

    Galaxy assembly bias on the red sequence , author=. , volume=. 2010 , publisher=

    2010

  73. [73]

    ascl:1010.046 , adsurl =

    indexf: Line-strength Indices in Fully Calibrated FITS Spectra. ascl:1010.046 , adsurl =

  74. [74]

    An optical/NIR survey of globular clusters in early-type galaxies. II. Ages of globular cluster systems and the relation to galaxy morphology. , keywords =. doi:10.1051/0004-6361/201015683 , archivePrefix =. 1010.4801 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201015683

  75. [75]

    , keywords =

    The ATLAS ^ 3D project - I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria. , keywords =. doi:10.1111/j.1365-2966.2010.18174.x , archivePrefix =. 1012.1551 , primaryClass =

    work page doi:10.1111/j.1365-2966.2010.18174.x 2010

  76. [76]

    XSL: The X-Shooter Spectral Library

    XSL: The X-Shooter Spectral Library. Journal of Physics Conference Series , year = 2011, series =. doi:10.1088/1742-6596/328/1/012023 , archivePrefix =. 1112.3651 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/1742-6596/328/1/012023 2011

  77. [77]

    , keywords =

    The old globular cluster system of NGC 4365: new VLT/FORS2 spectra. , keywords =. doi:10.1111/j.1365-2966.2012.22135.x , archivePrefix =. 1209.3020 , primaryClass =

    work page doi:10.1111/j.1365-2966.2012.22135.x 2012

  78. [78]

    Counting Low-Mass Stars in Integrated Light

    Counting Low-mass Stars in Integrated Light. , keywords =. doi:10.1088/0004-637X/747/1/69 , archivePrefix =. 1109.0007 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/747/1/69

  79. [79]

    The stellar initial mass function in early-type galaxies from absorption line spectroscopy. II. Results , author=. , volume=. 2012 , publisher=

    2012

  80. [80]

    M., Alatalo, K., et al

    Systematic variation of the stellar initial mass function in early-type galaxies. , archivePrefix = "arXiv", eprint =. doi:10.1038/nature10972 , adsurl =

    work page doi:10.1038/nature10972

Showing first 80 references.