scholarly journals Multiband observation of LIGO/Virgo binary black hole mergers in the gravitational-wave transient catalog GWTC-1

2020 ◽  
Vol 496 (1) ◽  
pp. 182-196 ◽  
Author(s):  
Chang Liu ◽  
Lijing Shao ◽  
Junjie Zhao ◽  
Yong Gao

ABSTRACT The Advanced LIGO and Virgo detectors opened a new era to study black holes (BHs) in our Universe. A population of stellar-mass binary black holes (BBHs) are discovered to be heavier than previously expected. These heavy BBHs provide us an opportunity to achieve multiband observation with ground-based and space-based gravitational-wave (GW) detectors. In this work, we use BBHs discovered by the LIGO/Virgo Collaboration as indubitable examples, and study in great detail the prospects for multiband observation with GW detectors in the near future. We apply the Fisher matrix to spinning, non-precessing inspiral-merger-ringdown waveforms, while taking the motion of space-based GW detectors fully into account. Our analysis shows that, detectors with decihertz sensitivity are expected to log stellar-mass BBH signals with very large signal-to-noise ratio and provide accurate parameter estimation, including the sky location and time to coalescence. Furthermore, the combination of multiple detectors will achieve unprecedented measurement of BBH properties. As an explicit example, we present the multiband sensitivity to the generic dipole radiation for BHs, which is vastly important for the equivalence principle in the foundation of gravitation, in particular for those theories that predict curvature-induced scalarization of BHs.

2020 ◽  
Vol 495 (1) ◽  
pp. 466-478 ◽  
Author(s):  
Shichao Wu ◽  
Zhoujian Cao ◽  
Zong-Hong Zhu

ABSTRACT In this article, we estimate the eccentricity of 10 binary black holes (BBHs) in the Gravitational-Wave Transient Catalog GWTC-1 by using the inspiral-only BBH waveform template EccentricFD. First, we test our method with simulated eccentric BBHs. Afterwards we apply the method to real BBH gravitational-wave data. We find that the BBHs in GWTC-1, with the exception of GW151226, GW170608 and GW170729, show very small eccentricity. Their upper limits on eccentricity range from 0.033–0.084 with 90 per cent credible interval at a reference frequency of 10 Hz. For GW151226, GW170608 and GW170729, the upper limits are higher than 0.1. The relatively large eccentricity of GW151226 and GW170729 is probably due to ignoring χeff and the low signal-to-noise ratio, and GW170608 is worthy of follow-up research. We also point out the limitations of the inspiral-only non-spinning waveform template in eccentricity measurement. Measurement of BBH eccentricity helps us to understand its formation mechanism. With an increase in the number of BBH gravitational-wave events and a more complete eccentric BBH waveform template, this will become a viable method in the near future.


Author(s):  
Manuel Arca Sedda ◽  
Christopher P. L. Berry ◽  
Karan Jani ◽  
Pau Amaro-Seoane ◽  
Pierre Auclair ◽  
...  

AbstractSince 2015 the gravitational-wave observations of LIGO and Virgo have transformed our understanding of compact-object binaries. In the years to come, ground-based gravitational-wave observatories such as LIGO, Virgo, and their successors will increase in sensitivity, discovering thousands of stellar-mass binaries. In the 2030s, the space-based LISA will provide gravitational-wave observations of massive black holes binaries. Between the $\sim 10$ ∼ 10 –103 Hz band of ground-based observatories and the $\sim 10^{-4}$ ∼ 1 0 − 4 –10− 1 Hz band of LISA lies the uncharted decihertz gravitational-wave band. We propose a Decihertz Observatory to study this frequency range, and to complement observations made by other detectors. Decihertz observatories are well suited to observation of intermediate-mass ($\sim 10^{2}$ ∼ 1 0 2 –104M⊙) black holes; they will be able to detect stellar-mass binaries days to years before they merge, providing early warning of nearby binary neutron star mergers and measurements of the eccentricity of binary black holes, and they will enable new tests of general relativity and the Standard Model of particle physics. Here we summarise how a Decihertz Observatory could provide unique insights into how black holes form and evolve across cosmic time, improve prospects for both multimessenger astronomy and multiband gravitational-wave astronomy, and enable new probes of gravity, particle physics and cosmology.


2020 ◽  
Vol 498 (2) ◽  
pp. 1905-1910 ◽  
Author(s):  
Gregory Ashton ◽  
Eric Thrane

ABSTRACT The gravitational-wave candidate GW151216 is a proposed binary black hole event from the first observing run of the Advanced LIGO detectors. Not identified as a bona fide signal by the LIGO–Virgo collaboration, there is disagreement as to its authenticity, which is quantified by pastro, the probability that the event is astrophysical in origin. Previous estimates of pastro from different groups range from 0.18 to 0.71, making it unclear whether this event should be included in population analyses, which typically require pastro > 0.5. Whether GW151216 is an astrophysical signal or not has implications for the population properties of stellar-mass black holes and hence the evolution of massive stars. Using the astrophysical odds, a Bayesian method that uses the signal coherence between detectors and a parametrized model of non-astrophysical detector noise, we find that pastro = 0.03, suggesting that GW151216 is unlikely to be a genuine signal. We also analyse GW150914 (the first gravitational-wave detection) and GW151012 (initially considered to be an ambiguous detection) and find pastro values of 1 and 0.997, respectively. We argue that the astrophysical odds presented here improve upon traditional methods for distinguishing signals from noise.


Author(s):  
Ju Chen ◽  
Changshuo Yan ◽  
Youjun Lu ◽  
Yuetong Zhao ◽  
Junqiang Ge

Abstract Gravitational wave (GW) signals from compact binary coalescences can be used as standard sirens to constrain cosmological parameters if its redshift can be measured independently by electromagnetic signals. However, mergers of stellar binary black holes (BBHs) may not have electromagnetic counterparts and thus have no direct redshift measurements. These dark sirens may be still used to statistically constrain cosmological parameters by combining their GW measured luminosity distances and localization with deep redshift surveys of galaxies around it. We investigate this dark siren method to constrain cosmological parameters in details by using mock BBH and galaxy samples. We find that the Hubble constant can be well constrained with an accuracy $\lesssim 1\%$ with a few tens or more BBH mergers at redshift up to $1$ if GW observations can provide accurate estimates of its luminosity distance (with relative error of $\lesssim 0.01$) and localization ($\lesssim 0.1\mathrm{deg}^2$), though the constraint may be significantly biased if the luminosity distance and localization errors are larger. We further generate mock BBH samples, according to current constraints on BBH merger rate and the distributions of BBH properties, and find that Deci-Hertz Observatory (DO) in a half year observation period may detect about one hundred BBHs with signal-to-noise ratio $\varrho \gtrsim 30$, relative luminosity distance error $\lesssim 0.02$, and localization error $\lesssim 0.01\mathrm{deg}^2$. By applying the dark standard siren method, we find that the Hubble constant can be constrained to $\sim 0.1-1\%$ level using these DO BBHs, an accuracy comparable to the constraints obtained by using electromagnetic observations in the near future, thus it may provide insight into the Hubble tension. We also demonstrate that the constraint on the Hubble constant using this dark siren method are robust and do not depend on the choice of the prior for the properties of BBH host galaxies.


2021 ◽  
Vol 923 (2) ◽  
pp. 139
Author(s):  
Fupeng Zhang ◽  
Xian Chen ◽  
Lijing Shao ◽  
Kohei Inayoshi

Abstract We study the stellar binary black holes (BBHs) inspiraling/merging in galactic nuclei based on our numerical method GNC. We find that 3%–40% of all newborn BBHs will finally merge due to various dynamical effects. In a five-year mission, up to 104, 105, and ∼100 of BBHs inspiraling/merging in galactic nuclei can be detected with signal-to-noise ration >8 in Advanced LIGO (aLIGO), Einstein/DECIGO, and TianQin/LISA/TaiJi, respectively. Roughly tens are detectable in both LISA/TaiJi/TianQin and aLIGO. These BBHs have two unique characteristics. (1) Significant eccentricities: 1%–3%, 2%–7%, or 30%–90% of them have e i > 0.1 when they enter into aLIGO, Einstein, or space observatories, respectively. Such high eccentricities provide a possible explanation for that of GW190521. Most highly eccentric BBHs are not detectable in LISA/Tianqin/TaiJi before entering into aLIGO/Einstein, as their strain becomes significant only at f GW ≳ 0.1 Hz. DECIGO becomes an ideal observatory to detect those events, as it can fully cover the rising phase. (2) Up to 2% of BBHs can inspiral/merge at distances ≲103 r SW from the massive black hole, with significant accelerations, such that the Doppler phase drift of ∼10–105 of them can be detected with signal-to-noise ratio >8 in space observatories. The energy density of the gravitational-wave backgrounds (GWBs) contributed by these BBHs deviates from the power-law slope of 2/3 at f GW ≲ 1 mHz. The high eccentricity, significant accelerations, and the different profile of the GWB of these sources make them distinguishable, and thus interesting for future gravitational-wave detections and tests of relativities.


2020 ◽  
Vol 498 (3) ◽  
pp. 4287-4294
Author(s):  
Jongsuk Hong ◽  
Abbas Askar ◽  
Mirek Giersz ◽  
Arkadiusz Hypki ◽  
Suk-Jin Yoon

ABSTRACT The dynamical formation of black hole binaries in globular clusters that merge due to gravitational waves occurs more frequently in higher stellar density. Meanwhile, the probability to form intermediate mass black holes (IMBHs) also increases with the density. To explore the impact of the formation and growth of IMBHs on the population of stellar mass black hole binaries from globular clusters, we analyse the existing large survey of Monte Carlo globular cluster simulation data (mocca-survey Database I). We show that the number of binary black hole mergers agrees with the prediction based on clusters’ initial properties when the IMBH mass is not massive enough or the IMBH seed forms at a later time. However, binary black hole formation and subsequent merger events are significantly reduced compared to the prediction when the present-day IMBH mass is more massive than ${\sim}10^4\, \rm M_{\odot }$ or the present-day IMBH mass exceeds about 1 per cent of cluster’s initial total mass. By examining the maximum black hole mass in the system at the moment of black hole binary escaping, we find that ∼90 per cent of the merging binary black holes escape before the formation and growth of the IMBH. Furthermore, large fraction of stellar mass black holes are merged into the IMBH or escape as single black holes from globular clusters in cases of massive IMBHs, which can lead to the significant underpopulation of binary black holes merging with gravitational waves by a factor of 2 depending on the clusters’ initial distributions.


2019 ◽  
Vol 490 (4) ◽  
pp. 5210-5216 ◽  
Author(s):  
Isobel M Romero-Shaw ◽  
Paul D Lasky ◽  
Eric Thrane

ABSTRACT Binary black holes are thought to form primarily via two channels: isolated evolution and dynamical formation. The component masses, spins, and eccentricity of a binary black hole system provide clues to its formation history. We focus on eccentricity, which can be a signature of dynamical formation. Employing the spin-aligned eccentric waveform model seobnre, we perform Bayesian inference to measure the eccentricity of binary black hole merger events in the first gravitational-wave transient catalogue of LIGO and Virgo. We find that all of these events are consistent with zero eccentricity. We set upper limits on eccentricity ranging from 0.02 to 0.05 with 90  per cent confidence at a reference frequency of $10\, {\rm Hz}$. These upper limits do not significantly constrain the fraction of LIGO–Virgo events formed dynamically in globular clusters, because only $\sim 5{{\ \rm per\ cent}}$ are expected to merge with measurable eccentricity. However, with the gravitational-wave transient catalogue set to expand dramatically over the coming months, it may soon be possible to significantly constrain the fraction of mergers taking place in globular clusters using eccentricity measurements.


2021 ◽  
Author(s):  
Hai-Cheng Feng ◽  
Hong-Tao Liu ◽  
Jinming Bai

Abstract Close supermassive binary black holes (SMBBHs) with separations less than about 0.1 parsec are expected to be Nano-Hertz gravitational wave sources. SMBBH systems should exhibit periodic variability. However, periodic variability in radio-loud quasars may be interpreted with the jet model. Here we report the detection of a robust periodic signal in the optical variability of the radio-quiet quasar PG 0923+201 with an observed period of 726.8±4.7 days, obtained from the sinusoid-like light curve of a temporal baseline of about 9 years. This periodicity is probably from a close SMBBH with a total mass of 109.3 solar masses and a separation of about 0.01 parsec, implying relativistic orbital speeds. Such a system has passed through the well-known “final parsec problem” of SMBBH systems, and the Nano-Hertz gravitational wave radiation becomes significant. The ratio of the separation between these two black holes to the broad-line region size is about 0.1. A close SMBBH is also suggested by this small ratio and the spectral properties of Balmer broad lines in this quasar. This radio-quiet quasar is a candidate emitter of Nano-Hertz gravitational waves at a frequency of about 30 Nano-Hertz.


2020 ◽  
Vol 500 (3) ◽  
pp. 4095-4109
Author(s):  
Rosa Valiante ◽  
Monica Colpi ◽  
Raffaella Schneider ◽  
Alberto Mangiagli ◽  
Matteo Bonetti ◽  
...  

ABSTRACT Third-generation ground-based gravitational wave interferometers, like the Einstein Telescope (ET), Cosmic Explorer, and the Laser Interferometer Space Antenna (LISA), will detect coalescing binary black holes over a wide mass spectrum and across all cosmic epochs. We track the cosmological growth of the earliest light and heavy seeds that swiftly transit into the supermassive domain using a semi-analytical model for the formation of quasars at z = 6.4, 2, and 0.2, in which we follow black hole coalescences driven by triple interactions. We find that light-seed binaries of several $10^2 \, {\rm M_\odot }$ are accessible to ET with a signal-to-noise ratio (S/N) of 10–20 at 6 < z < 15. They then enter the LISA domain with larger S/N as they grow to a few $10^4 \, {\rm M_\odot }$. Detecting their gravitational signal would provide first time evidence that light seeds form, grow, and dynamically pair during galaxy mergers. The electromagnetic emission of accreting black holes of similar mass and redshift is too faint to be detected even for the deepest future facilities. ET will be our only chance to discover light seeds forming at cosmic dawn. At 2 < z < 8, we predict a population of ‘starved binaries’, long-lived marginally growing light-seed pairs, to be loud sources in the ET bandwidth (S/N > 20). Mergers involving heavy seeds (${\sim} 10^5\!-\!10^6 \, {\rm M_\odot }$) would be within reach up to z = 20 in the LISA frequency domain. The lower z model predicts $11.25 \, (18.7)$ ET (LISA) events per year, overall.


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