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The Butcher-Oemler Effect in 295 Clusters: Strong Redshift Evolution and Cluster Richness Dependence

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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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V. E. Margoniner (1, 2), R. R. de Carvalho (2), R. R. Gal (3), S. G. Djorgovski (4) ((1) Bell Laboratories, (2) Observatorio Nacional, (3) Caltech)

Astrophysics · Submitted 10 Nov 2000

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

The authors' main claim The two parameters, z, and a consistently defined projected galaxy number density, N, together account for all of the observed variation in f_B within the measurement errors.

how it is stated · asserted 1.00 read the record →

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arXiv IDastro-ph/0011210 (version 1)
Pith ID7P5DGPDP, Pith's permanent record of this paper and its review
Citation2), (2) Observatorio Nacional, (3) Caltech), R. R. de Carvalho (2), R. R. Gal (3), S. G. Djorgovski (4) ((1) Bell Laboratories, V. E. Margoniner (1. "The Butcher-Oemler Effect in 295 Clusters: Strong Redshift Evolution and Cluster Richness Dependence." arXiv:astro-ph/0011210 (2000). https://pith.science/paper/7P5DGPDP
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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, 4,978 input tokens.

What the abstract itself states, as probabilities: claims first 0.12 · states limitation 0.19 · human participants 0.02 · controlled comparison 0.10 · randomized assignment 0.01 · states quantitative result 0.65 · compares with prior results 0.66 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

We examine the Butcher-Oemler effect and its cluster richness dependence in the largest sample studied to date: 295 Abell clusters. We find a strong correlation between cluster richness and the fraction of blue galaxies, f_B, at every redshift. The slope of the f_B(z) relation is similar for all richnesses, but at a given redshift, f_B is systematically higher for poor clusters. This is the chief cause of scatter in the f_B vs. z diagram: the spread caused by the richness dependence is comparable to the trend in f_B over a typical redshift baseline, so that conclusions drawn from smaller samples have varied widely. The two parameters, z, and a consistently defined projected galaxy number density, N, together account for all of the observed variation in f_B within the measurement errors. The redshift evolution of f_B is real, and occurs at approximately the same rate for clusters of all richness classes.

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 examine the Butcher-Oemler effect and its cluster richness dependence in the largest sample studied to date: 295 Abell clusters. contribution 0.99 0.88 0.05 asserted 0.91
s1 We find a strong correlation between cluster richness and the fraction of blue galaxies, f_B, at every redshift. result 1.00 0.97 0.30 asserted 1.00
s2 The slope of the f_B(z) relation is similar for all richnesses, but at a given redshift, f_B is systematically higher for poor clusters. result 1.00 0.93 0.19 asserted 1.00
s3 This is the chief cause of scatter in the f_B vs. z diagram: the spread caused by the richness dependence is comparable to the trend in f_B over a typical redshift baseline, so that conclusions drawn from smaller samples have varied widely. interpretation 0.91 0.79 0.21 asserted 1.00
s4 The two parameters, z, and a consistently defined projected galaxy number density, N, together account for all of the observed variation in f_B within the measurement errors. result 0.98 0.92 0.41 asserted 1.00
s5 The redshift evolution of f_B is real, and occurs at approximately the same rate for clusters of all richness classes. result 0.96 0.93 0.28 asserted 1.00

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from analysis of existing data 0.68.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • 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 examine the Butcher-Oemler effect and its cluster richness dependence in the largest sample studied to date: 295 Abell clusters. We find a strong correlation between cluster richness and the fraction of blue galaxies, f_B, at every redshift. The slope of the f_B(z) relation is similar for all richnesses, but at a given redshift, f_B is systematically higher for poor clusters. This is the chief cause of scatter in the f_B vs. z diagram: the spread caused by the richness dependence is comparable to the trend in f_B over a typical redshift baseline, so that conclusions drawn from smaller samples have varied widely. The two parameters, z, and a consistently defined projected galaxy number density, N, together account for all of the observed variation in f_B within the measurement errors. The redshift evolution of f_B is real, and occurs at approximately the same rate for clusters of all richness classes.

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