Bibliographic record
Abstract
This thesis is concerned with the targeting of emission line galaxies with FMOS (Fibre Multi-Object Spectrograph) to determine properties of star forming galaxies at redshift ~1.5, and provide measurements of the growth rate of large-scale structure through Redshift Space Distortions (RSDs). I also consider the opportunities of targeting the passive galaxy population at high redshift, through measurements of their continuum. I start with the extensive broad-band photometric data available in the UKIDSS-UDS (United Kingdom Infrared Telescope Deep Sky Survey - Ultra-Deep Survey) field which is used to produce a band-merged catalogue, later used for determining photometric redshifts. In producing this catalogue, I approach the issue of source confusion present in the deep Spitzer imaging using z-band priors on profile position and shape and an iterative Expectation-Maximisation algorithm. Photometric redshift estimates are compared against colour selections as potential targeting techniques for a wide-area redshift survey with FMOS. Different photometry survey areas are considered, and the quality of selection given the available broad-band data tested, by adjusting the photometric catalogue produced for the UDS. The results indicate that the SWIRE (Spitzer Wide area InfraRed Extragalactic Survey) fields are too small to provide adequate sources with a consistent selection mechanism. The CFHTLS (Canada-Frace-Hawaii Telescope Legacy Survey) would have a large enough area given deeper z'-band imaging, and SWIRE-depth coverage in the Spitzer 3.6μm and 4.5μm bands. I present FMOS commissioning data obtained for the UDS field, including the spectroscopic targeting of sources form the High-Z Emission Line Survey (HiZELS). With this data, I am able to test the current quality of flux calibration using cool stars targeted simultaneously and the level of systematic errors left by sky-subtraction. The sample of HiZELS sources selected to place Hα at z~1.45 show low contamination from other emission lines, and only one out of 9 targets assigned a redshift has any indication of AGN activity. Finally, I present longslit observations of faint, passive galaxies at redshift z~1.9, selected as members of a possible cluster, JKCS 041, selected from broad band colours. One object was observed with high enough signal to noise to constrain the position of the 4000 Å / Balmer break, providing a tighter constraint on the photometric redshift of 1.8867 <sup>+0.0034</sup> -0.0117.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
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".