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A Young Stellar Cluster in the Nucleus of NGC 4449

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Paper breakdownThe authors' claims, conditions and measurements, as JSON Signed receiptProof this review has not been altered
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T. Boeker, R. P. van der Marel, L. Mazzuca, H.-W. Rix, G. Rudnick, L. C. Ho, J. C. Shields

Astrophysics · Submitted 26 Oct 2000

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

The authors' main claim The light is clearly dominated by a very young (6-10 Myr) population of stars.

how it is stated · asserted 1.00 read the record →

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arXiv IDastro-ph/0010542 (version 2)
Pith IDNJIGLOQK, Pith's permanent record of this paper and its review
CitationG. Rudnick, H.-W. Rix, J. C. Shields, L. C. Ho, L. Mazzuca, R. P. van der Marel, T. Boeker. "A Young Stellar Cluster in the Nucleus of NGC 4449." arXiv:astro-ph/0010542 (2000). https://pith.science/paper/NJIGLOQK
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The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

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Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-09-23: 1 request, 4,938 input tokens.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.10 · human participants 0.01 · controlled comparison 0.12 · randomized assignment 0.01 · states quantitative result 0.98 · compares with prior results 0.87 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; .

We have obtained 1-2 A resolution optical Echellette spectra of the nuclear star cluster in the nearby starburst galaxy NGC 4449. The light is clearly dominated by a very young (6-10 Myr) population of stars. For our age dating, we have used recent population synthesis models to interpret the observed equivalent width of stellar absorption features such as the HI Balmer series and the CaII triplet around 8500 A. We also compare the observed spectrum of the nuclear cluster to synthesized spectra of simple stellar populations of varying ages. All these approaches yield a consistent cluster age. Metallicity estimates based on the relative intensities of various ionization lines yield no evidence for significant enrichment in the center of this low mass galaxy: the metallicity of the nuclear cluster is about one fourth of the solar value, in agreement with independent estimates for the disk material of NGC 4449.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We have obtained 1-2 A resolution optical Echellette spectra of the nuclear star cluster in the nearby starburst galaxy NGC 4449. method 0.76 0.97 0.04 asserted 1.00
s1 The light is clearly dominated by a very young (6-10 Myr) population of stars. result 1.00 0.88 0.72 asserted 1.00
s2 For our age dating, we have used recent population synthesis models to interpret the observed equivalent width of stellar absorption features such as the HI Balmer series and the CaII triplet around 8500 A. method 1.00 0.92 0.04 asserted 0.98
s3 We also compare the observed spectrum of the nuclear cluster to synthesized spectra of simple stellar populations of varying ages. method 0.99 0.93 0.03 asserted 0.95
s4 All these approaches yield a consistent cluster age. result 0.89 0.89 0.13 asserted 0.99
s5 Metallicity estimates based on the relative intensities of various ionization lines yield no evidence for significant enrichment in the center of this low mass galaxy: the metallicity of the nuclear cluster is about one fourth of the solar value, in agreement with independent estimates for the disk material of NGC 4449. result 0.99 0.92 0.28 asserted 0.97

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

What was examined, and what was not

sources read
  • arXiv listing abstract v2
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
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  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

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

The paper
Original abstract

We have obtained 1-2 A resolution optical Echellette spectra of the nuclear star cluster in the nearby starburst galaxy NGC 4449. The light is clearly dominated by a very young (6-10 Myr) population of stars. For our age dating, we have used recent population synthesis models to interpret the observed equivalent width of stellar absorption features such as the HI Balmer series and the CaII triplet around 8500 A. We also compare the observed spectrum of the nuclear cluster to synthesized spectra of simple stellar populations of varying ages. All these approaches yield a consistent cluster age. Metallicity estimates based on the relative intensities of various ionization lines yield no evidence for significant enrichment in the center of this low mass galaxy: the metallicity of the nuclear cluster is about one fourth of the solar value, in agreement with independent estimates for the disk material of NGC 4449.

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