An Extended and More Sensitive Search for Periodicities in Rossi X-ray Timing Explorer/all-sky Monitor X-ray Light Curves

Abstract

We present the results of a systematic search in ~14 years of Rossi X-ray Timing Explorer All-Sky Monitor (ASM) data for evidence of periodicities. Two variations of the commonly used Fourier analysis search method have been employed to significantly improve upon the sensitivity achieved by Wen et al. in 2006, who also searched for periodicities in ASM data. In addition, the present search is comprehensive in terms of sources studied and frequency range covered, and has yielded the detection of the signatures of the orbital periods of eight low-mass X-ray binary systems and of ten high-mass X-ray binaries not listed in the tables of Wen et al. Orbital periods, epochs, signal amplitudes, modulation fractions, and folded light curves are given for each of these systems. Seven of the orbital periods are the most precise reported to date. In the course of this work, the 18.545 day orbital period of IGR J18483–0311 was co-discovered, and the first detections in X-rays were made of the ~3.9 day orbital period of LMC X-1 and the ~3.79 hr orbital period of 4U 1636–536. The results inform future searches for orbital and other periodicities in X-ray binaries.