Confirming pulsar candidates using a multi-day phase alignment search
Bibliographic record
Abstract
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope is a low-frequency (400-800 MHz) drift-scan radio telescope located near Penticton, British Columbia. The CHIME telescope has proven not only an excellent fast radio burst (FRB) detector, but also useful for finding pulsars, thus far in single burst searches. The CHIME All-sky Multiday Pulsar Stacking Search (CHAMPSS) project searches for pulsars in the Fourier-transformed CHIME/FRB time-series data. These power spectra are searched daily, but also stacked over timescales of months to a year to increase the power of weaker pulsars. Due to the daily cadence of CHIME and its large field of view, CHAMPSS is well positioned to find intermittent pulsars, pulsars away from the Galactic plane, and weaker pulsars, thus acting as a probe of previously under explored regions of the pulsar population parameter space. In this thesis, a method for confirming candidate pulsar signals found within these power spectra stacks is described. This confirmation method aligns dedispersed and folded time series data in phase over multiple days in order to increase the signal-to-noise ratio (SNR) of the integrated pulse profile, which may not be significant enough for detection by folding just a single day of observations. I compare the expected and observed SNR of known pulsars detected in the CHAMPSS commissioning surveys. I also describe how I calculate the flux densities of new pulsars discovered by CHAMPSS. Finally, the 11 new pulsars discovered by CHAMPSS and confirmed using the methods in this thesis are briefly described, as well as future prospects
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".