Gravitational wave background from neutron star phase transition

Fan

2011

ApJ

We revisit the possibility and detectability of a stochastic gravitational wave (GW) background produced by a cosmological population of newborn neutron stars (NSs) with r-mode instabilities. The NS formation rate is derived from both observational and simulated cosmic star formation rates (CSFRs). We show that the resultant GW background is insensitive to the choice of CSFR models, but depends strongly on the evolving behavior of CSFR at low redshifts. Nonlinear effects such as differential rotation, suggested to be an unavoidable feature which greatly influences the saturation amplitude of r-mode, are considered to account for GW emission from individual sources. Our results show that the dimensionless energy density Ω GW could have a peak amplitude of ≃ (1 − 3.5) × 10 −8 in the frequency range (200 − 1000) Hz, if the smallest amount of differential rotation corresponding to a saturation amplitude of order unity is assumed. However, such a high mode amplitude is unrealistic as it is known that the maximum value is much smaller and at most 10 −2 . A realistic estimate of Ω GW should be at least 4 orders of magnitude lower (∼ 10 −12 ), which leads to a pessimistic outlook for the detection of r-mode background. We consider different pairs of terrestrial interferometers (IFOs) and compare two approaches to combine multiple IFOs in order to evaluate the detectability of this GW background. Constraints on the total emitted GW energy associated with this mechanism to produce a detectable stochastic background (a SNR of 2.56 with 3-year cross correlation) are ∼ 10 −3 M ⊙ c 2 for two co-located advanced LIGO detectors, and 2×10 −5 M ⊙ c 2 for two Einstein Telescopes. These constraints may also be applicable to alternative GW emission mechanisms related to oscillations or instabilities in NSs depending on the frequency band where most GWs are emitted.

Section: Introductionmentioning

confidence: 99%

STOCHASTIC GRAVITATIONAL WAVE BACKGROUND FROM NEUTRON STARr-MODE INSTABILITY REVISITED

Fan

2011

ApJ

“…An astrophysically produced SGWB would arise from the ensemble of what would be considered to be standard astrophysical events 31 . In total the astrophysical background would be the result of a broad spectrum of events, including core collapses to neutron stars or black holes 32,33,34,35,9 , rotating neutron stars 36,37 including magnetars 38,39,40,41 , phase transitions 42,43 or initial instabilities in young neutron stars 44,45,46,45 , compact binary mergers 47,48,49,50,51,52 and compact objects around super-massive black holes 53,54 . As LIGO and Virgo observe in the advanced detector era, the cosmologically produced SGWB and the astrophysically produced SGWB are both exciting targets for observation.…”

Section: Introductionmentioning

confidence: 99%

Implications of the binary coalescence events found in O1 and O2 for the stochastic background of gravitational events

Christensen

2019

Preprint

The Advanced LIGO and Advanced Virgo detectors have commenced observations. Gravitational waves from the merger of binary black hole systems and a binary neutron star system have been observed. A major goal for LIGO and Virgo is to detect or set limits on a stochastic background of gravitational waves. A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved cosmological and/or astrophysical sources. A cosmologically produced background would carry unique signatures from the earliest epochs in the evolution of the Universe. Similarly, an astrophysical background would provide information about the astrophysical sources that generated it. The observation of gravitational waves from compact binary mergers implies that there will be a stochastic background from these sources that could be observed by Advanced LIGO and Advanced Virgo in the coming years. The LIGO and Virgo search for a stochastic background should probe interesting regions of the parameter space for numerous astrophysical and cosmological models. Presented here is an outline of LIGO and Virgo's search strategies for a stochastic background of gravitational waves, including the search for gravitational wave polarizations outside of what is predicted from general relativity. Also discussed is how global electromagnetic noise (from the Schumann resonances) could affect this search; possible strategies to monitor and subtract this potential source of correlated noise in a the global detector network are explained. The results from Advanced LIGO's observing runs O1 and O2 will be presented, along with the implications of the gravitational wave detections. The future goals for Advanced LIGO and Advanced Virgo will be explained.

The Fourteenth Marcel Grossmann Meeting

“…21,22 An astrophysically produced SGWB would arise from the ensemble of what would be considered to be standard astrophysical events. 23 In total the astrophysical background would be the result of a broad spectrum of events, including core collapses to neutron stars or black holes [24][25][26][27] , rotating neutron stars 28,29 including magnetars [30][31][32][33] , phase transition 34,35 or initial instabilities in young neutron stars 36,37,37,38 , compact binary mergers [39][40][41][42][43][44] and compact objects around supermassive black holes. 45,46 A foreground of astrophysical sources could potentially mask cosmologically produced signals.…”

Section: Introductionmentioning

confidence: 99%

Strategies and goals for stochastic gravitational wave background searches with Advanced LIGO and Advanced Virgo

Christensen

2017

The Advanced LIGO detectors commenced observations in September of 2015, while Advanced Virgo will come on-line in 2016. They will approach their target sensitivities over the subsequent years. A major goal for LIGO and Virgo will be to detect or set limits on a stochastic background of gravitational waves. A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved cosmological and/or astrophysical sources. A cosmologically produced background would carry unique signatures from the earliest epochs in the evolution of the Universe. Similarly, an astrophysical background would provide information about the astrophysical sources that generated it. LIGO and Virgo observations should be able to probe interesting regions of parameter space for these models. Presented here is an outline of LIGO and Virgo's search strategies for these signals. Also discussed is how global electromagnetic noise (from the Schumann resonances) could affect this search; possible strategies to monitor and subtract this potential source of correlated noise in a the global detector network are explained.