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Record W2068588156 · doi:10.1086/341708

Ten Billion Years of Galaxy Evolution

2002· article· en· W2068588156 on OpenAlexaff

Bibliographic record

VenuePublications of the Astronomical Society of the Pacific · 2002
Typearticle
Languageen
FieldPhysics and Astronomy
TopicGalaxies: Formation, Evolution, Phenomena
Canadian institutionsHerzberg Institute of Astrophysics
Fundersnot available
KeywordsGalaxyStar formationBillion yearsGalaxy formation and evolutionIrregular galaxyElliptical galaxyHubble sequenceIntergalactic star

Abstract

fetched live from OpenAlex

Observations in the Hubble Deep Fields have been used to study the evolution of galaxy morphology over time. The majority of galaxies with z <1 are seen to be disklike, whereas most objects with z >2 appear to be either chaotic or centrally concentrated "blobs." Such blobs might be the ancestral objects of ellipticals or of galaxy bulges. About 1 / 3 of objects with z >2 appear to be in the process of merging. The region with 1< z <2 marks an important transition in the global history of star formation from a merger‐dominated regime at z >2 to one at z <1 in which most star formation takes place in galactic disks. It is speculated that the break in the Madau plot at z ∼ 1.5 might be related to the transition from merger‐dominated star formation at z >2 to disk‐dominated star formation at z <1. The Hubble tuning‐fork diagram provides a satisfactory framework only for galaxy classification at z ≤0.5. At z >0.5, barred spirals become increasingly rare. Possibly very young disks are still too hot (chaotic) to become unstable in global barlike modes. Furthermore, it becomes increasingly difficult to shoehorn galaxies at z ≥0.5 into the Hubble classification sequence E–Sa–Sb–Sc. The fraction of "peculiar" spirals, i.e., those that do not fit naturally into the Hubble tuning‐fork diagram, increases from 12% at z ∼ 0.0 to 46% at 0.6< z <0.8. Early‐type galaxies appear to approach their normal morphology faster than do late‐type spirals. As a result, only ∼5% of E–Sa–Sab galaxies are peculiar at z ∼ 0.7, compared to 69% peculiars among objects of types Sbc–Sc. With increasing redshift, the spiral‐arm pattern in late‐type spirals is seen to become ever more chaotic. In early‐type galaxies, the spiral arms appear to be less well developed at large redshifts than they are at z ∼ 0. Finally, a very tentative, and entirely empirical, scheme is proposed for the classification of objects with z >2.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.007
Threshold uncertainty score0.023

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.002
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.002
Science and technology studies0.0000.000
Scholarly communication0.0010.001
Open science0.0000.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0070.002

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.010
GPT teacher head0.194
Teacher spread0.183 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations46
Published2002
Admission routes1
Has abstractyes

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