A Deep Pulse Search in 11 Low Mass X-Ray Binaries
Abstract
We present a systematic coherent X-ray pulsation search in 11 low mass X-ray binaries (LMXBs). We select a relatively broad variety of LMXBs, including persistent and transient sources, spanning orbital periods between 0.3 and 17 hr. We use about 3.6 Ms of data collected by the Rossi X-Ray Timing Explorer and XMM-Newton and apply a semi-coherent search strategy to look for weak and persistent pulses in a wide spin frequency range. We find no evidence for X-ray pulsations in these systems and consequently set upper limits on the pulsed sinusoidal semi-amplitude below 1.6% for ten outbursting/persistent LMXBs and 6% for a quiescent system; the upper limits are further refined, by searching a narrower parameter space around the outliers, down to 0.14%-0.78% and 2.9%, respectively. These results suggest that weak pulsations might not form in (most) non pulsating LMXBs.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2018
- DOI:
- 10.3847/1538-4357/aabf89
- arXiv:
- arXiv:1709.10408
- Bibcode:
- 2018ApJ...859..112P
- Keywords:
-
- binaries: general;
- stars: neutron;
- stars: rotation;
- X-rays: binaries;
- X-rays: stars;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- submitted to ApJ, 8 pages