Gravitational waves from Sco X-1: A comparison of search methods and prospects for detection with advanced detectors

Abstract

The low-mass X-ray binary Scorpius X-1 (Sco X-1) is potentially the most luminous source of continuous gravitational-wave radiation for interferometers such as LIGO and Virgo. For low-mass X-ray binaries this radiation would be sustained by active accretion of matter from its binary companion. With the Advanced Detector Era fast approaching, work is underway to develop an array of robust tools for maximizing the science and detection potential of Sco X-1. We describe the plans and progress of a project designed to compare the numerous independent search algorithms currently available. We employ a mock-data challenge in which the search pipelines are tested for their relative proficiencies in parameter estimation, computational efficiency, robust- ness, and most importantly, search sensitivity. The mock-data challenge data contains an ensemble of 50 Scorpius X-1 (Sco X-1) type signals, simulated within a frequency band of 50-1500 Hz. Simulated detector noise was generated assuming the expected best strain sensitivity of Advanced LIGO and Advanced VIRGO ($4\times 10^{-24}$ Hz${}^{-1/2}$). A distribution of signal amplitudes was then chosen so as to allow a useful comparison of search methodologies. A factor of 2 in strain separates the quietest detected signal, at $6.8\times 10^{-26}$ strain, from the torque-balance limit at a spin frequency of 300 Hz, although this limit could range from $1.2\times 10^{-25}$ (25 Hz) to $2.2\times 10^{-26}$ (750 Hz) depending on the unknown frequency of Sco X-1. With future improvements to the search algorithms and using advanced detector data, our expectations for probing below the theoretical torque-balance strain limit are optimistic.

33 pages, 11 figures

References in corpus (15)

• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• Advanced LIGO
• A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)
• Detecting gravitational wave emission from the known accreting neutron stars
• Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
• Upper limit map of a background of gravitational waves
• Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
• Detecting gravitational waves from mountains on neutron stars in the Advanced Detector Era
• The cross-correlation search for periodic gravitational waves
• First all-sky search for continuous gravitational waves from unknown sources in binary systems
• NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038
• Directed searches for continuous gravitational waves from binary systems: parameter-space metrics and optimal Scorpius X-1 sensitivity
• A directed search for gravitational waves from Scorpius X-1 with initial LIGO
• Model-Based Cross-Correlation Search for Gravitational Waves from Scorpius X-1
• A fast search strategy for gravitational waves from low-mass X-ray binaries

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