Galaudage, S., Wette, K., Galloway, D. K. and Messenger, C. (2022) Deep searches for X-ray pulsations from Scorpius X-1 and Cygnus X-2 in support of continuous gravitational wave searches. Monthly Notices of the Royal Astronomical Society, 509(2), pp. 1745-1754. (doi: 10.1093/mnras/stab3095)
Text
258644.pdf - Accepted Version 1MB |
Abstract
Neutron stars in low mass X-ray binaries are hypothesised to emit continuous gravitational waves that may be detectable by ground-based observatories. The torque balance model predicts that a higher accretion rate produces larger-amplitude gravitational waves, hence low mass X-ray binaries with high X-ray flux are promising targets for gravitational wave searches. The detection of X-ray pulsations would identify the spin frequency of these neutron stars, and thereby improve the sensitivity of continuous gravitational-wave searches by reducing the volume of the search parameter space. We perform a semi-coherent search for pulsations in the two low mass X-ray binaries Scorpius X-1 and Cygnus X-2 using X-ray data from the Rossi X-ray Timing Explorer Proportional Counter Array. We find no clear evidence for pulsations, and obtain upper limits (at 90 per cent confidence) on the fractional pulse amplitude, with the most stringent being 0.034 per cent for Scorpius X-1 and 0.23 per cent for Cygnus X-2. These upper limits improve upon those in previous work by factors of ∼8.2 and ∼1.6 respectively.
Item Type: | Articles |
---|---|
Additional Information: | This research was conducted by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), through project number CE170100004. The authors also gratefully acknowledge the Science and Technology Facilities Council of the United Kingdom. CM is supported by the Science and Technology Research Council (grant No. ST/L000946/1). This research has made use of data and software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory. The searches for X-ray pulsations were performed on the OzSTAR national facility at Swinburne University of Technology. OzSTAR is funded by Swinburne University of Technology and the National Collaborative Research Infrastructure Strategy (NCRIS). |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Messenger, Dr Christopher |
Authors: | Galaudage, S., Wette, K., Galloway, D. K., and Messenger, C. |
College/School: | College of Science and Engineering > School of Physics and Astronomy |
Research Centre: | College of Science and Engineering > School of Physics and Astronomy > Institute for Gravitational Research |
Journal Name: | Monthly Notices of the Royal Astronomical Society |
Publisher: | Oxford University Press (OUP) |
ISSN: | 1365-2966 |
ISSN (Online): | 1365-2966 |
Published Online: | 27 October 2021 |
Copyright Holders: | Copyright © 2021 The Authors |
First Published: | Monthly Notices of the Royal Astronomical Society 509(2):1745–1754 |
Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher |
Related URLs: |
University Staff: Request a correction | Enlighten Editors: Update this record