A VLBI Calibration System with Real-time Pulsar Gating for FRB Localization using CHIME/FRB Outriggers
Bibliographic record
Abstract
Several thousand fast radio burst (FRB) sources have been discovered using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope, as part of the CHIME/FRB project. Currently, CHIME/FRB is able to localize most FRBs to a limiting precision of several arcminutes, which can be improved to subarcminute precision for some FRB sources through offline analysis of their baseband data. This allows only the most nearby sources to be robustly associated with a host galaxy. Using three new Outrigger telescopes located at transcontinental distances from CHIME, the CHIME/FRB Outriggers project will improve the localization capabilities of CHIME/FRB. Together, these radio telescopes will form a wide field of view, very long baseline interferometry (VLBI) array that will enable FRBs discovered by CHIME/FRB to be localized to a limiting precision of ~50 milliarcseconds. The astrometric position of each FRB will be determined using calibration solutions derived from well-localized radio pulsars and compact, steady radio sources. We present an overview of the VLBI calibration system that will be employed within the CHIME/FRB Outrigger project to achieve high precision FRB localizations, which will enable studies of a large number of FRB host galaxies and local environments.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.006 |
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".