Precision Ephemerides For Gravitational Wave Searches: II. Cyg X-2

Abstract

Accreting neutron stars in low-mass X-ray binaries (LMXBs) are candidate high-frequency persistent gravitational wave sources. These may be detectable with next generation interferometers such as Advanced LIGO/VIRGO within this decade. However, the search sensitivity is expected to be limited principally by the uncertainty in the binary system parameters. We combine new optical spectroscopy of Cyg X-2 obtained with the Liverpool Telescope (LT) with available historical radial velocity data, which gives us improved orbital parameter uncertainties based on a 44-year baseline. We obtained an improvement of a factor of 2.6 in the orbital period precision and a factor of 2 in the epoch of inferior conjunction T_0. The updated orbital parameters imply a mass function of 0.65 +/- 0.01 M_sun, leading to a primary mass (M_1) of 1.67 +/- 0.22 M_sun (for i=62.5 +/- 4 deg). In addition, we estimate the likely orbital parameter precision through to the expected Advanced LIGO and VIRGO detector observing period and quantify the corresponding improvement in sensitivity via the required number of templates.

arXiv comment7 pages, 3 figures, accepted for publication by ApJ

References in corpus (21)

• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• Gravitational Radiation and Rotation of Accreting Neutron Stars
• Nuclear-Powered Millisecond Pulsars and the Maximum Spin Frequency of Neutron Stars
• Detecting gravitational wave emission from the known accreting neutron stars
• Thermonuclear burst oscillations
• The Optical Light Curves of Cygnus X-2 (V1341 Cyg) and the Mass of its Neutron Star
• Coherent searches for periodic gravitational waves from unknown isolated sources and Scorpius X-1: results from the second LIGO science run
• Quasi-periodic X-ray brightness fluctuations in an accreting millisecond pulsar
• The mass of the neutron star in Cyg X-2 (V1341 Cyg)
• Upper limit map of a background of gravitational waves
• Detecting gravitational waves from mountains on neutron stars in the Advanced Detector Era
• Discovery of KiloHertz Quasi-Periodic Oscillations in the Z source Cygnus X-2
• Is there a link between the neutron-star spin and the frequency of the kilohertz quasi-periodic oscillations?
• Discovery of kHz QPOs and shifted frequency correlations in the accreting millisecond pulsar XTE J1807--294
• Gravitational waves from Sco X-1: A comparison of search methods and prospects for detection with advanced detectors
• On the mass of the neutron star in Cyg X-2
• Precision ephemerides for gravitational-wave searches: I. Sco X-1
• The correlations between the spin frequencies and kHz QPOs of Neutron Stars in LMXBs
• Searching for continuous gravitational wave sources in binary systems
• Optical spectroscopy and Doppler tomography of Cygnus X-2
• The Liverpool Telescope Spectrograph: FRODOSpec

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• Searches for continuous gravitational waves from neutron stars: A twenty-year retrospective
• Low Mass X-ray Binaries: The Effects of the Magnetic Braking Prescription
• Hidden Markov model tracking of continuous gravitational waves from a binary neutron star with wandering spin. II. Binary orbital phase tracking
• Evidence for mass-dependent peculiar velocities in compact object binaries: Towards better constraints on natal kicks
• Intermittent dipping in a low-mass X-ray Binary
• Hidden Markov model tracking of continuous gravitational waves from a neutron star with wandering spin. III. Rotational phase tracking
• Search for Gravitational Waves from Scorpius X-1 in LIGO O3 Data With Corrected Orbital Ephemeris
• Deep searches for X-ray pulsations from Scorpius X-1 and Cygnus X-2 in support of continuous gravitational wave searches