The future of polarimetry at the NOIRLab Gemini North Observatory facility
Bibliographic record
Abstract
Polarimetric observations can provide important information on many astrophysical phenomena beyond that available via conventional imaging and spectroscopy alone. As a first step toward providing Gemini North instrument support for polarimetric observations, an instrument upgrade program is currently under way to bring one of the GPOL polarization modulator units (GPOL-N) into operation in concert with NIRI at Gemini North (GN) to provide an IR imaging polarimetry in the visiting instrument mode. Featuring three deployable trays that accommodate swappable, rotatable polarizing waveplates and calibration polarizers, GPOL is designed to facilitate polarimetric observations over the opticalinfrared wavelength range of 0.3 – 5 μm. When installed on the telescope, GPOL is physically situated inside the Acquisition and Guidance (A&G) unit, and is designed to work in concert with bottom port instruments containing an oninstrument Wollaston prism, such as NIRI. We present here an overview of the functional characteristics of GPOL and the current status of the GPOL+NIRI commissioning project. Following control board and software updates, the GPOL-N unit is currently undergoing further testing as a prelude to refurbishment. We also briefly discuss subsequent Gemini North polarimetric instrumentation plans, which include the possible future commissioning of a visitor mode that combines GPOL with the GNIRS multifunction spectrograph to provide NIR spectropolarimetry, and polarimetric imaging via the GPI 2.0 instrument.
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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 | 0.009 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.007 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.010 | 0.005 |
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".