Observational Studies of Interacting Galaxies and the Development of the Wide Integral Field Infrared Spectrograph
Bibliographic record
Abstract
Interacting galaxies are thought to be the essential building blocks of elliptical galaxies under the hierarchical galaxy formation scenario. The goal of my dissertation is to broaden our understanding of galaxy merger evolution through both observational studies and instrument developments. Observationally, I approach the goal photometrically and spectroscopically. The photometric studies better constrain the number density evolution of wet and dry mergers through five CFHTLS broad band photometry up to z~1. Meanwhile, by comparing the merger and elliptical galaxy mass density function, I discovered that the most massive mergers are not all formed via merging processes, unless the merging timescale is much longer than the expected value. Spectroscopically, the kinematic properties of close pair galaxies were studied to understand how star formation were quenched at z~0.5. I discovered that the number of red-red pairs are rare, which does not support the gravitational quenching mechanism suggested by the hot halo model. In instrumentation, one efficient way to study galaxy mergers is to use the integral field spectroscopic technique, capitalizing its intrinsic capability of obtaining 2-D spectra effectively. However, the currently available integral field spectrographs are inadequate to provide the required combination of integral field size and spectral resolution for merger studies. I, therefore, have developed two optical designs of a wide integral field infrared spectrograph (WIFIS), which I call WIFIS1 and WIFIS2, to satisfy the requirements of merger studies. Both the designs provide an integral field of 12" x 5" on 10-m telescopes (or equivalently 52" x 20" on 2.3-m telescopes). WIFIS1 delivers spectral resolving powers of 5,500 covering each of JHK bands in a single exposure; WIFIS2 does a lower power of 3,000 focusing on a shorter wavebands of zJ and H bands. All the WIFIS2 optical components have either been or being fabricated, and some of the components have been characterized in the laboratory, including its integral field unit, gratings, and mirrors. The expected completion of WIFIS based on WIFIS2 is 2013 summer, which will be followed by WIFIS1-based spectrograph in a few years.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 source (direct Gemma or distilled Codex), 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".