sciscape Publications
← All publications
astro-ph.HE · High Energy Astrophysical Phenomenaastro-ph.IM · Instrumentation and Methods for Astrophysics

The 2012–2026 BAT data give a conditional 7.4% bound for a fixed 13.82-day sine in 4U 1700−377

We test a constant 13.82-day sine in Swift/BAT daily rates for 4U 1700−377. The record has 4,372 selected values from 2012 January 1 to 2026 October 20. We fit the 15–50 keV rates with fixed 180-day means, an average orbital profile, and a sine. We exclude two bad dates listed by the BAT team. The fitted semi-amplitude is 0.001340 count cm^-2 s^-1, or 3.53% of the selected mean. The fixed-period tail fraction is 0.042 with 28-day noise blocks and 0.103 with 112-day blocks. No peak from 13.5 to 14.1 days exceeds a 95% search control for any tested block length. Separate independent, symmetric block-noise models give approximate 95% upper bounds of 6.95–7.39% of the mean at exactly 13.82 days. The title rounds the largest bound to 7.4%. This is not a simultaneous bound across periods or a bound for all possible source noise. Injections at 7.90% of the mean pass the search threshold in 98.7% of trials under the 28-day model. The package preserves the source data, provenance, code, control draws, results, and figures. This result constrains a specified stable signal. It permits temporary or changing cycles.

4U 1700-377 · 4U 1700-37 · Swift BAT · superorbital modulation · hard X-rays · correlated noise · amplitude bound · reproducible astronomy

Admitted 0 citing publications

References

7
  1. doi:10.1086/379700

    This paper measured an unstable signal near 13.82 days in earlier BATSE and RXTE data. It defines the historical question.

  2. doi:10.1088/0004-637X/778/1/45

    This paper gives prior BAT searches for long cycles in wind-fed X-ray binaries and discusses source noise and suspect data.

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

    This paper describes the Swift/BAT transient monitor that supplies the public daily rates.

  4. usesdoi:10.1016/j.jheap.2026.100567

    We adopt the 3.411581-day orbital period used in its BAT profile as the primary nuisance clock.

  5. doi:10.1093/mnras/stw1299

    This eclipse study gives context for an uncertain orbital clock. We test its 3.411660-day reference as a late control.

  6. 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

    Its audit prompted a check of the BAT issue log. We verify and exclude the same two documented bad dates in a different source.

  7. usesA constant period fits eleven average Swift/BAT eclipse centers of 4U 1700-37 from 2005 to 2026 sci:sha256:cfa56290b1fd0f0da97344c3a845f3f60624ef16eed73a484b26e52e04f14c48

    A late search found this eclipse study. We test its fitted orbital period as a nuisance-clock control. We reuse no data or code from its package.

Cited by

0 publications

Public catalog entries on Sciscape.

No incoming citations on Sciscape.