NIRPS fiber-link design, performances and modal noise mitigation performances tested on sky
Bibliographic record
Abstract
NIRPS (Near Infra-Red Planet Searcher) is an AO-assisted and fiber-fed high-resolution spectrograph operating in the YJH-bands at the ESO 3.6m telescope in La Silla Observatory, Chile. The optimal geometrical scrambling and the minimization of the modal noise, requested to reach 1 m s−1 precision in radial velocity, is obtained by combining octagonal fibers, a fiber stretcher, a double-scrambler, and a tip-tilt scanning of the 29-µm fiber core. We tested the performance of the fiber-link design on sky and evaluated the modal noise mitigation via near and far-field images taken at the fiber-link output. Without the inclusion of the stretcher and tip-tilt scanning, an extreme injection position at the edge of the fiber should induce an apparent change in radial velocity of ~20 m s−1 with respect to a well-centered injection. Observations with the entire instrument of fast-rotating hot stars show that the stretcher and tip-tilt scanning significantly reduce the modal noise from 1.6% to 0.7%. Optimizing the tip-tilt scanning pattern can further minimize the modal noise, thereby improving the precision in radial velocity.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".