Notice bibliographique
Résumé
This thesis charts the evolution of the Universal Star Formation Rate Density (SFRD) across the redshift range 0.2 < z < 0.6, using the 2nd Canadian Network for Observational Cosmology Survey (CN0C2). The redshift range covered by the Survey marks an important transitional period in the history of the Universe, over which the SFRD is thought to undergo rapid evolution. The various Star Formation Rate (SFR) indicators from the literature are reviewed and it is shown that the [OII] forbidden emission line can provide a very similar SFR to that reported by the Ha recombination line, if reddening is accounted for. We explain the CN0C2 Survey in detail, including the observation strategy and the instrumentation used. The Survey weighting scheme is also discussed. The purpose written code, used to measure the strengths of the [OII] emission line in each of the Survey spectra, is explained and tested, against both another automated code and by-eye measurements from IRAF. The procedure of re-normalising the on equivalent width errors that are reported by the code is also detailed. This leaves the line measurement errors very well quantified. We investigate the accuracy of the photometric redshift codes ImpZ and Hyperz in returning dust estimates, A(_v) from photometry alone. The benchmark for this comparison is set by Balmer Decrement measurements of a sub-set of the CN0C2 dataset. Combining the [OII] line strength measurements with the dust correction from the photometric redshift code ImpZ, we compute SFRs for individual galaxies in the CN0C2 Survey. These are combined with a weighting scheme to chart the evolution of SFRD with redshift and luminosity. It is found that giant galaxies undergo a strong evolution in terms of the fraction of those galaxies that are rapidly star forming, but that the absolute SFRD from giants does not change as quickly as that from lower luminosity galaxies. At all redshifts and luminosities covered by the Survey, galaxies with [OII] emission <30Å contribute roughly half the total SFRD. This means narrow band imaging surveys may miss a large fraction of star formation activity at those epochs. At z ~ 0.25 it is found that dwarf galaxies dominate the overall SFRD, in-keeping with results from the local Universe. We produce a best estimate Lilly-Madau plot based on our findings and compare it to several studies from the literature. It is shown that although the overall rise found by previous studies is confirmed, the shape of the rise is not consistent with other works, showing a sharper increase at low (0.2 < z < 0.4) redshift followed by a slowing at z ~0.6. The significance of this result remains unquantified however.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».