LIGO/Virgo S190814bv: CFHTphotometryof AT2019npv
Bibliographic record
Abstract
Using the MegaPrime/MegaCam instrument (1x1 deg FOV) at the Canada-France-Hawaii Telescope, we observed the candidate AT2019npv reported by Goldstein et al (GCN 25393) close to a galaxy at z=0.056 (Jonker et al, GCN 25454), which was a candidate electromagnetic counterpart of the GW event S190814bv (LIGO/Virgo Collaboration, GCN 25324, GCN. 25333). Multiple images were obtained with the CFHT for this object in g(210sx2), r(240sx2) and i(300sx2) bands beginning at 2019-08-24 13:08 UTC. Using references from the DECam Legacy Survey (DECaLS), we performed image differencing in g and r-bands, with a low significance detection in g-band and an r-band estimate of r_AB = 23.0+-0.05 mag (i-band has a significant detection, but the reference is not available and therefore the numbers are unreliable). This object has been ruled out by different spectroscopic observations and photometric archival analysis as being related to the LIGO/Virgo GW candidate (GCN25468, GCN25475, GCN25478). GCN OPS NOTE(27aug19): Per author's request, the last reference in the last sentence was changed from "GCN5478" to "GCN25478"; and C. Corre was added to the author list.]
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.017 | 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".