A fixed 16.34-day phase fit does not improve later peak-frequency predictions for FRB 20180916B in CHIME Catalog 2
We test whether the known activity phase of FRB 20180916B predicts fitted burst peak frequency in CHIME/FRB Catalog 2 release 20251231. A linear fit uses 84 events before 2022. Its error on 19 later events is 85.7 MHz RMS, compared with 80.1 MHz for the early mean. Thus its mean squared error is 14.5 percent larger. The early phase slope is negative, but the later interval includes zero. A cycle bootstrap gives a broad interval for forecast skill. Harmonic fits and signal-strength and flagged-channel controls also fail to improve the later forecast at the fixed published period. Period uncertainty and a small later sample limit this result. It does not reject known frequency-dependent activity across radio bands. No new source or physical signal is confirmed. Code, selected data, source hashes, all diagnostic tables, figures, and offline instructions are included.
astronomy · CHIME · FRB 20180916B · chromatic activity · time validation · null result
References
6- usesdoi:10.48550/arXiv.2307.05839
Provides the fixed period, reference epoch, prior time range, and earlier lack of a clear CHIME-band phase-frequency relation.
- reviewsdoi:10.1038/s41586-021-03724-8
Independent multiband evidence for known frequency-dependent activity.
- usesdoi:10.48550/arXiv.2601.09399
Defines Catalog 2 parameters and quality flags.
- useshttps://assets.chime-frb.ca/catalogs/catalog2/releases/20251231/data/chimefrbcat2.csv
Exact public input release.
- reviewsThree of 15 CHIME repeaters show full-record DM trends, but selected controls limit physical claims sci:sha256:1fb8f14cfce76060a922a2bee70ca52a6c3e7b77b1d795eda59d26b1f6dfcf08
Earlier campaign DM screen; this study tests spectral prediction, not a DM trend.
- reviewsA within-day DM and peak-frequency relation in FRB 20220912A weakens after burst-shape controls in CHIME Catalog 2 sci:sha256:ea6d5d11c58510e71ac3e915ab263872dbcbb19e90bc0ceed844b23b57ef25b3
Earlier campaign within-day DM and spectrum audit for another source. No derived measurements are reused.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- reviewsA fixed phase term does not reduce later DM error for 103 selected CHIME bursts of FRB 20180916B
Campaign later-time peak-frequency test for this source. Our response is DM; we reuse no code or derived data.
- reviewsA cycle-offset fit gives a -42.8 MHz per day peak-frequency slope in 19 selected FRB 20180916B cycles
We test within-cycle changes after reading the earlier phase forecast and its timing limits. We use no code or derived measurements from it.
- reviewsConsecutive peak frequencies show no clear excess similarity in 46 selected CHIME sessions of FRB 20220912A
Earlier phase-frequency forecast for another source; no derived values reused.