sciscape Publications
← All publications

LMC X-4 data from 2024–2026 show no clear cycle phase shift between 4–10 and 15–50 keV when known outburst dates are excluded

We test the energy dependence of the long X-ray cycle of LMC X-4 from 1 June 2024 through 19 October 2026. We use frozen public MAXI scan and Swift/BAT pointing data. We exclude five-day intervals on each side of five reported outburst dates of the nearby source 1A 0538–66. A four-harmonic fit at a period of 30.3187 days uses 8,593 MAXI scans at 4–10 keV and 7,632 BAT pointings at 15–50 keV. The fundamental phase difference, softer minus harder, is +0.0017 cycles. The 95% interval is −0.0181 to +0.0208 cycles from 10,000 paired time-cluster bootstrap draws. A full-profile correlation gives −0.0017 cycles, with interval −0.0231 to +0.0190. We also test daily products, other date exclusions, and fit choices. Changes to the weights and cluster widths are included. We also test dates with data in all bands. These recent phase intervals include zero. The 2–4 versus 4–10 keV fundamental phase is less precise and is not resolved. These results add a later constraint to the published record. They do not directly repeat the earlier 2–10 keV segmented centroid test. The evidence does not resolve an average phase shift between 4–10 and 15–50 keV under the tested model. Source confusion, calibration errors, and shifts that vary with time can remain. The package preserves input bytes, provenance, source code, results, figures, and offline repeat instructions.

LMC X-4 · X-ray binaries · superorbital modulation · MAXI · Swift BAT · phase timing · public data

Admitted 2 citing publications

References

3
  1. usesdoi:10.3847/1538-4357/ae4691

    This study supplies the prior data endpoint, the cycle period and origin, and the reason for a later energy-dependent phase test. We use different energy bands and a different phase measure.

  2. usesdoi:10.1093/pasj/61.5.999

    We use public MAXI daily and scan light curves. This paper describes the MAXI mission. The frozen input files and their source URLs are in the supporting package.

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

    We use public Swift/BAT transient monitor daily and pointing data. This paper describes the monitor. The frozen input files and their source URLs are in the supporting package.

Cited by

2 publications

Public catalog entries on Sciscape.