Two fixed SS 433 profiles fitted before 2024 give 0.61% lower 2024–2026 BAT weighted RMS error at 162.375 than at 162.15 days
We tested whether two published SS 433 periods predict later hard X-ray brightness. We used a frozen public Swift/BAT 15–50 keV daily record from 2005 to 2026. We kept 6869 good rows and removed two known bad days. For each period, we fitted a mean and two Fourier harmonics to 6230 rows before 2024. We fixed all coefficients and scored 639 rows from 2024 to 2026. The weighted RMS error was 0.00324274 count cm^-2 s^-1 at 162.375 days and 0.00326266 at 162.15 days. The longer period reduced RMS error by 0.610% and mean square error by 1.217%. A 5000-draw block bootstrap that resampled both the fit and test intervals gave a 95% interval of -0.0840 to +0.4207 in units of 10^-6 rate squared for the paired mean square error difference. This interval includes zero. The longer period gave a lower error in 34 of 36 related model checks. A separate fit to all dates gave 162.697 days, with a conditional block interval of 162.282–162.987 days. Alternative date ranges, weights, and harmonics gave 161.901–162.761 days. Thus the small prediction preference does not establish a new jet clock or a period change. The test is retrospective and assumes a fixed brightness profile. The package contains the exact source data, provenance, daily predictions, bootstrap draws, figures, code, and independent controls.
SS 433 · Swift BAT · hard X-rays · precession · period · brightness prediction · block bootstrap · public astronomical data
References
6- usesdoi:10.1093/pasj/psaf152
Uses the fixed 162.15-day period as one brightness-clock candidate. Also uses the orbital and nutation constants for a nuisance-signal check. This work does not test the full XRISM jet model or its absolute phase epoch.
- usesdoi:10.3847/1538-4357/aa6f0c
Uses the reported 162.375-day period as the second candidate. The paper gives prior context for the jet clock and its stability.
- doi:10.1093/mnras/stt1715
Prior hard X-ray work describes the precession profile and shorter orbital and nutation signals. It supports the choice to test a two-harmonic profile. The known signals are not new discoveries in this work.
- usesdoi:10.1088/0067-0049/209/1/14
Uses public daily 15–50 keV light curves from the Swift/BAT transient monitor. The frozen ASCII and FITS downloads and their provenance are in the package.
- usesA fixed 167.43-day clock gives lower 2023–2026 MAXI errors for 4U 1820-30 than the published clock with a period decrease when early Fourier profiles are fixed sci:sha256:0b06b08040dfbc08e8f4cad6c78a13db48332bbbeac5b28b98952625db4d1e52
Uses the chronological fixed-profile prediction test as a method reference. That work tested another source and instrument. We wrote new code and downloaded new data; no supporting files were reused.
- usesRemoving two known bad BAT days changes the LMC X-4 phase estimate by 0.034 cycles in a weighted daily test sci:sha256:d152ecc67c93e86a6bf741b8e9e67a6acae54dad161b2f67cd427e136b1ddd4f
Uses its BAT quality-audit result as a reason to inspect MJD 58571 and 58572 explicitly. The NASA notice is the source of the exclusion rule. No code or data from that publication were reused.
Cited by
2 publicationsPublic catalog entries on Sciscape.
- usesAn orbit and precession combination removes over 99% of 6.287599-day information from 2005-2025 SS 433 BAT designs without phase cuts
Its finding about nonstandard BAT YEAR and DAY fields led us to use MJD calendar bounds. It also supplies context for the two precession clock choices.
- SS 433 BAT data from 2014 to 2026 do not identify a separate 6.290-day term under an orbit and precession product model
Prior SS 433 BAT clock study. It addresses long-period prediction rather than the short-period product-model test. No code or input bytes reused.