Detectability of continuous gravitational waves from isolated neutron stars in the Milky Way

Aims. We estimate the number of pulsars, detectable as continuous gravitational wave sources with the current and future gravitational-wave detectors, assuming a simple phenomenological model of evolving non-axisymmetry of the rotating neutron star. Methods. We employed a numerical model of the Galactic neutron star population, with the properties established by comparison with radio observations of isolated Galactic pulsars. We generated an arbitrarily large synthetic population of neutron stars and evolved their period, magnetic field, and position in space. We used a gravitational wave emission model based on exponentially decaying ellipticity (i.e. non-axisymmetry of the star) with no assumption of the origin of a given ellipticity. We calculated the expected signal in a given detector for a one-year observation, and assumed a detection criterion of the signal-to-noise ratio of 11.4, comparable to a targeted continous wave search. We analysed the detectable population separately in each detector: Advanced LIGO, Advanced Virgo, and the planned Einstein Telescope. In the calculation of the expected signal we neglect the frequency change of the signals due to the source’s spindown and the Earth’s motion with respect to the solar barycentre. Results. With conservative values for the neutron star evolution (a supernova rate of once per 100 years, initial ellipticity ϵ0 ≃ 10−5 with no decay of the ellipticity η = thub ≃ 104 Myr), the expected number of detected neutron stars is 0.15 (based on a simulation of 10 M stars) for the Advanced LIGO detector. A broader study of the parameter space (ϵ0, η) is presented. With the planned sensitivity for the Einstein Telescope, and assuming the same ellipiticity model, the expected detection number is 26.4 pulsars during a one-year observing run.

[1]  M. J. Williams,et al.  GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo during the First Half of the Third Observing Run , 2021 .

[2]  Von Welch,et al.  Reproducing GW150914: The First Observation of Gravitational Waves From a Binary Black Hole Merger , 2016, Computing in Science & Engineering.

[3]  B. Machenschalk,et al.  Einstein@Home All-sky Search for Continuous Gravitational Waves in LIGO O2 Public Data , 2020, The Astrophysical Journal.

[4]  Reinhard Prix,et al.  Deep-learning continuous gravitational waves: Multiple detectors and realistic noise , 2020, 2005.04140.

[5]  M. Papa,et al.  Results from the First All-Sky Search for Continuous Gravitational Waves from Small-Ellipticity Sources. , 2020, Physical review letters.

[6]  C. Broeck,et al.  Science case for the Einstein telescope , 2019, Journal of Cosmology and Astroparticle Physics.

[7]  Y. N. Liu,et al.  Multi-messenger Observations of a Binary Neutron Star Merger , 2019, Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019).

[8]  T. Bulik,et al.  Markov Chain Monte Carlo population synthesis of single radio pulsars in the Galaxy , 2018, Monthly Notices of the Royal Astronomical Society.

[9]  M. Bejger,et al.  Continuous Gravitational Waves from Neutron Stars: Current Status and Prospects , 2019, Universe.

[10]  B. Owen,et al.  How to search for gravitational waves from r -modes of known pulsars , 2019, Physical Review D.

[11]  M. S. Shahriar,et al.  All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO O2 data , 2019 .

[12]  P. Leaci,et al.  A new data analysis framework for the search of continuous gravitational wave signals , 2018, Classical and Quantum Gravity.

[13]  Andrew L. Miller,et al.  Method to search for long duration gravitational wave transients from isolated neutron stars using the generalized frequency-Hough transform , 2018, Physical Review D.

[14]  K. Wette,et al.  Fast and accurate sensitivity estimation for continuous-gravitational-wave searches , 2018, Physical Review D.

[15]  P. Lasky,et al.  Evidence for a Minimum Ellipticity in Millisecond Pulsars , 2018, The Astrophysical Journal.

[16]  B. A. Boom,et al.  Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA , 2013, Living Reviews in Relativity.

[17]  K. Riles,et al.  Recent searches for continuous gravitational waves , 2017, 1712.05897.

[18]  B. A. Boom,et al.  GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral. , 2017, Physical review letters.

[19]  Texas Tech University,et al.  Multi-messenger observations of a binary neutron star merger , 2017, 1710.05833.

[20]  B. A. Boom,et al.  Sensitivity Improvements in the Search for Periodic Gravitational Waves Using O1 LIGO Data. , 2019, Physical review letters.

[21]  Y. Wang,et al.  First Low-Frequency Einstein@Home All-Sky Search for Continuous Gravitational Waves in Advanced LIGO Data , 2017, 1707.02669.

[22]  Paul D. Lasky,et al.  Gravitational Waves from Neutron Stars: A Review , 2015, Publications of the Astronomical Society of Australia.

[23]  M. S. Shahriar,et al.  Characterization of the LIGO detectors during their sixth science run , 2014, 1410.7764.

[24]  C. Broeck,et al.  Advanced Virgo: a second-generation interferometric gravitational wave detector , 2014, 1408.3978.

[25]  C. Palomba,et al.  Method for all-sky searches of continuous gravitational wave signals using the frequency-Hough transform , 2014, 1407.8333.

[26]  F. Barone,et al.  Advanced Virgo: a 2nd generation interferometric gravitational wave detector , 2014 .

[27]  S. Bose,et al.  Sensitivity studies for third-generation gravitational wave observatories , 2010, 1012.0908.

[28]  C. Palomba,et al.  A method for detection of known sources of continuous gravitational wave signals in non-stationary data , 2010 .

[29]  Benno Willke,et al.  The Einstein Telescope: a third-generation gravitational wave observatory , 2010 .

[30]  B. Krishnan,et al.  Gravitational waves from neutron stars: promises and challenges , 2009, 0912.0384.

[31]  B. Kızıltan,et al.  CONSTRAINTS ON PULSAR EVOLUTION: THE JOINT PERIOD–SPIN-DOWN DISTRIBUTION OF MILLISECOND PULSARS , 2009, 0902.0604.

[32]  et al,et al.  Einstein@Home search for periodic gravitational waves in LIGO S4 data , 2008, 0804.1747.

[33]  A. Królak,et al.  Analysis of Gravitational-Wave Data: Index , 2009 .

[34]  F. Antonucci,et al.  Detection of periodic gravitational wave sources by Hough transform in the f versus plane , 2008, 0807.5065.

[35]  B. Allen,et al.  Blandford's argument: The strongest continuous gravitational wave signal , 2008, 0804.3075.

[36]  A. Zezas,et al.  Compact Object Modeling with the StarTrack Population Synthesis Code , 2005, astro-ph/0511811.

[37]  G. Woan,et al.  Bayesian estimation of pulsar parameters from gravitational wave data , 2005, gr-qc/0508096.

[38]  D. Lorimer,et al.  A statistical study of 233 pulsar proper motions , 2005, astro-ph/0504584.

[39]  R. Manchester,et al.  The Australia Telescope National Facility Pulsar Catalogue , 2005 .

[40]  C. Palomba.  Simulation of a population of isolated neutron stars evolving through the emission of gravitational waves , 2005, astro-ph/0503046.

[41]  B. Krishnan,et al.  Hough transform search for continuous gravitational waves , 2004, gr-qc/0407001.

[42]  E. al.,et al.  Setting upper limits on the strength of periodic gravitational waves using the first science data from the GEO600 and LIGO detectors , 2003, gr-qc/0308050.

[43]  N. Stergioulas,et al.  On the Relevance of the r-Mode Instability for Accreting Neutron Stars and White Dwarfs , 1998, astro-ph/9806089.

[44]  Lars Bildsten,et al.  Gravitational Radiation and Rotation of Accreting Neutron Stars , 1998, astro-ph/9804325.

[45]  Bernard F. Schutz,et al.  Gravitational waves from hot young rapidly rotating neutron stars , 1998, gr-qc/9804044.

[46]  B. Schutz,et al.  Data analysis of gravitational-wave signals from spinning neutron stars. I. The signal and its detection , 1998, gr-qc/9804014.

[47]  Benjamin J. Owen,et al.  Gravitational Radiation Instability in Hot Young Neutron Stars , 1998, gr-qc/9803053.

[48]  H. Ritter,et al.  The line of death, the line of birth , 1994 .

[49]  D. Bhattacharya,et al.  Formation and evolution of binary and millisecond radio pulsars , 1991 .

[50]  M. Zimmermann,et al.  Gravitational waves from rotating and precessing rigid bodies - Simple models and applications to pulsars , 1979 .

[51]  W. Press,et al.  Gravitational-wave astronomy , 1972 .

[52]  I. McLure.  Classical and Quantum , 1971 .

[53]  W. Y. Chau,et al.  Gravitational Radiation and the Oblique Rotator Model , 1970, Nature.

[54]  H. Melosh.  Estimate of the Gravitational Radiation from NP 0532 , 1969, Nature.

[55]  J. Gunn,et al.  On the nature of pulsars. I - Theory. , 1969 .