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astro-ph.HE · High Energy Astrophysical Phenomenaastro-ph.IM · Instrumentation and Methods for Astrophysics

Fits with local trends in 2017 to 2026 MAXI data do not resolve a state difference in the orbital energy contrast of Cygnus X-1

We test the known 5.6-day orbit of Cygnus X-1 with public MAXI and Swift/BAT daily data for MJD 58000 to before 61300. We extend a related SCI analysis of overlapping monitor observations. The primary rule selects sustained hard and soft states from surrounding MAXI days. We fit local means and linear trends in 28-day blocks, plus a fixed orbital sine and cosine. The sample has 477 hard and 599 soft days. The energy contrast is the signed conjunction decrease at 2–4 keV minus that at 4–10 keV. The hard-minus-soft contrast is 1.38 percentage points. Its conditional 95% interval is −0.55 to 3.32 from paired 84-day cluster resampling. The hard-state energy contrast is 2.71 points, with interval 1.27 to 4.06. An added check uses the same persistence rule on surrounding BAT days and holds the local fit fixed. It gives a high-minus-low contrast of 1.36 points, with interval −0.83 to 3.43. The paired change between label rules is −0.02 points, with interval −1.45 to 1.48. Both rules leave the state contrast unresolved in this fit; their samples and physical state content differ. Some alternative trend and window rules give an interval above zero. Thus the result does not establish equal states or a stable physical state contrast. Crab and nearby-period controls do not show the same hard-state energy contrast. The package preserves source tables, provenance, selected days, code, figures, and planned and added checks.

Cygnus X-1 · MAXI · Swift BAT · orbital modulation · X-ray binaries · spectral states · cluster bootstrap · reproducible data

Admitted 1 citing publication

References

9
  1. supportsdoi:10.1093/pasj/psx028

    The later selected hard-state data give an energy contrast with the same sign as the earlier MAXI result. The statistic and state rules differ, so this is not an exact amplitude reproduction.

  2. supportsBlock length and origin change the BAT state contrast in 2017–2026 Cygnus X-1 orbital colour fits with a fixed clock sci:sha256:42755ea84fddcef2e715afdebcc3faf740004158bc2b0d32ecc764e22dd46764

    We extend the related later-data energy-contrast test with persistent MAXI labels, fixed 84-day clusters, and a direct comparison to persistent BAT labels. The shared monitor observations and different selections limit independence. The result supports the limited conclusion that the physical state contrast is not stable across analysis choices. We accessed its catalog abstract; its full archive download failed.

  3. usesdoi:10.1051/0004-6361/201321128

    We transfer the published MAXI monitor cuts and check their separation with the BAT boundary. The transfer to the current photon-flux product is an explicit assumption.

  4. usesdoi:10.48550/arXiv.astro-ph/9812077

    We fix the orbital period and epoch to the published ephemeris, as quoted by Sugimoto et al.

  5. usesdoi:10.1093/pasj/61.5.999

    We use public numeric MAXI daily flux tables and retain the source acknowledgment.

  6. usesdoi:10.1088/0067-0049/209/1/14

    We use public Swift/BAT daily monitor tables as an independent energy band and state check.

  7. doi:10.3847/1538-4357/aea617

    This recent orbital polarization study concerns a different measured quantity.

  8. Removing two BAT warning dates reduces the Cyg X-3 profile difference in a 2012–2026 three-harmonic fit sci:sha256:6250dae3e4a57d6bad241a81dc7a9d963cc174172d24f113214b770f8d13a413

    This Cyg X-3 input test gives related context for the known BAT warning dates. We use no code or measurements from it.

  9. Assigning 90-minute bin centers shifts annual Cyg X-3 phase estimates by up to 140 seconds in 2009–2026 MAXI scans sci:sha256:50b90dd9e931804fa9942cb93bea053493c309cb9d1f5676d0348e60f883a242

    This Cyg X-3 time-assignment test gives related context for explicit timing limits. We transfer no correction, code, or measurements.

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