
Physics and Astronomy Faculty Publications and Presentations
Document Type
Article
Publication Date
2-23-2017
Abstract
Scorpius X-1 (Sco X-1) and x-ray transient XTE J1751-305 are low-mass x-ray binaries (LMXBs) that may emit continuous gravitational waves detectable in the band of ground-based interferometric observatories. Neutron stars in LMXBs could reach a torque-balance steady-state equilibrium in which angular momentum addition from infalling matter from the binary companion is balanced by angular momentum loss, conceivably due to gravitational-wave emission. Torque balance predicts a scale for detectable gravitational-wave strain based on observed x-ray flux. This paper describes a search for Sco X-1 and XTE J1751-305 in LIGO science run 6 data using the TwoSpect algorithm, based on searching for orbital modulations in the frequency domain. While no detections are claimed, upper limits on continuous gravitational-wave emission from Sco X-1 are obtained, spanning gravitational-wave frequencies from 40 to 2040 Hz and projected semimajor axes from 0.90 to 1.98 light-seconds. These upper limits are injection validated, equal any previous set in initial LIGO data, and extend over a broader parameter range. At optimal strain sensitivity, achieved at 165 Hz, the 95% confidence level random-polarization upper limit on dimensionless strain ℎ0 is approximately 1.8 ×10−24. The closest approach to the torque-balance limit, within a factor of 27, is also at 165 Hz. Upper limits are set in particular narrow frequency bands of interest for J1751-305. These are the first upper limits known to date on 𝑟-mode emission from this XTE source. The TwoSpect method will be used in upcoming searches of Advanced LIGO and Virgo data.
Recommended Citation
Meadors, Grant David, Evan Goetz, Keith Riles, Teviet Creighton, and Florent Robinet. "Searches for continuous gravitational waves from Scorpius X-1 and XTE J1751-305 in LIGO’s sixth science run." Physical Review D 95, no. 4 (2017): 042005. https://doi.org/10.1103/PhysRevD.95.042005
Publication Title
Physical Review D
DOI
https://doi.org/10.1103/PhysRevD.95.042005
Comments
© 2017 American Physical Society Original published version https://doi.org/10.1103/PhysRevD.95.042005