Gravitational waves × HI intensity mapping: cosmological and astrophysical applications

Abstract Two of the most rapidly growing observables in cosmology and astrophysics are gravitational waves (GW) and the neutral hydrogen (HI) distribution. In this work, we investigate the cross-correlation between resolved gravitational wave detections and HI signal from intensity mapping (IM) experiments. By using a tomographic approach with angular power spectra, including all projection effects, we explore possible applications of the combination of the Einstein Telescope and the SKAO intensity mapping surveys. We focus on three main topics: (i) statistical inference of the observed redshift distribution of GWs; (ii) constraints on dynamical dark energy models as an example of cosmological studies; (iii) determination of the nature of the progenitors of merging binary black holes, distinguishing between primordial and astrophysical origin. Our results show that: (i) the GW redshift distribution can be calibrated with good accuracy at low redshifts, without any assumptions on cosmology or astrophysics, potentially providing a way to probe astrophysical and cosmological models; (ii) the constrains on the dynamical dark energy parameters are competitive with IM-only experiments, in a complementary way and potentially with less systematics; (iii) it will be possible to detect a relatively small abundance of primordial black holes within the gravitational waves from resolved mergers. Our results extend towards GW × IM the promising field of multi-tracing cosmology and astrophysics, which has the major advantage of allowing scientific investigations in ways that would not be possible by looking at single observables separately.

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On Primordial Black Holes and secondary gravitational waves generated from inflation with solo/multi-bumpy potential

Chinese Physics C ◽

10.1088/1674-1137/ac42bd ◽

2021 ◽

Author(s):

Rui feng Zheng ◽

Jia ming Shi ◽

Taotao Qiu

Keyword(s):

Black Holes ◽

Black Hole ◽

Gravitational Waves ◽

Power Spectra ◽

Small Scale ◽

Primordial Black Hole ◽

Primordial Black Holes ◽

Slow Roll ◽

Spherical Collapse ◽

Scalar Perturbations

Abstract It is well known that primordial black hole (PBH) can be generated in inflation process of the early universe, especially when the inflaton field has some non-trivial features that could break the slow-roll condition. In this paper, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We found that potential with multi-bump can give rise to power spectra with multi peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical collapse and elliptical collapse. And discusses the scalar-induced gravitational waves (SIGWs) generated by the second-order scalar perturbations.

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Enriching the symphony of gravitational waves from binary black holes by tuning higher harmonics

Physical Review D ◽

10.1103/physrevd.98.084028 ◽

2018 ◽

Vol 98 (8) ◽

Cited By ~ 60

Author(s):

Roberto Cotesta ◽

Alessandra Buonanno ◽

Alejandro Bohé ◽

Andrea Taracchini ◽

Ian Hinder ◽

...

Keyword(s):

Black Holes ◽

Gravitational Waves ◽

Higher Harmonics ◽

Binary Black Holes

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Tests of CPT invariance in gravitational waves with LIGO-Virgo catalog GWTC-1

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08628-x ◽

2020 ◽

Vol 80 (11) ◽

Author(s):

Sai Wang ◽

Zhi-Chao Zhao

Keyword(s):

Black Holes ◽

Dispersion Relation ◽

Gravitational Waves ◽

Cpt Violation ◽

Cpt Invariance ◽

Binary Black Holes ◽

Better Than

AbstractA discovery of gravitational waves from binary black holes raises a possibility that measurements of them can provide strict tests of CPT invariance in gravitational waves. When CPT violation exists, if any, gravitational waves with different circular polarizations could gain a slight difference in propagating speeds. Hence, the birefringence of gravitational waves is induced and there should be a rotation of plus and cross modes. For CPT-violating dispersion relation $${\omega ^{2}=k^{2}}$$ ω 2 = k 2 $${\pm 2\zeta k^{3}}$$ ± 2 ζ k 3 , where a sign $${\pm }$$ ± denotes different circular polarizations, we find no substantial deviations from CPT invariance in gravitational waves by analyzing a compilation of ten signals of binary black holes in the LIGO-Virgo catalog GWTC-1. We obtain a strict constraint on the CPT-violating parameter, i.e., $$\zeta =0.14^{+0.22}_{-0.31}\times 10^{-15}\,\text {m}$$ ζ = 0 . 14 - 0.31 + 0.22 × 10 - 15 m , which is around two orders of magnitude better than the existing one. Therefore, this study stands for the up-to-date strictest tests of CPT invariance in gravitational waves.

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Gravitational waves from Population III binary black holes formed by dynamical capture

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1362 ◽

2020 ◽

Vol 495 (2) ◽

pp. 2475-2495 ◽

Cited By ~ 3

Author(s):

Boyuan Liu ◽

Volker Bromm

Keyword(s):

Black Holes ◽

Binary Stars ◽

First Generation ◽

High Redshift ◽

Ex Situ ◽

Binary Black Holes ◽

Formation Pathway ◽

Einstein Telescope ◽

Population Iii

ABSTRACT We use cosmological hydrodynamic simulations to study the gravitational wave (GW) signals from high-redshift binary black holes (BBHs) formed by dynamical capture (ex situ formation channel). We in particular focus on black holes (BHs) originating from the first generation of massive, metal-poor, so-called Population III (Pop III) stars. An alternative (in situ) formation pathway arises in Pop III binary stars whose GWligi signature has been intensively studied. In our optimistic model, we predict a local GW event rate density for ex situ BBHs (formed at z > 4) of ∼0.04 yr−1 Gpc−3. This is comparable to or even higher than the conservative predictions of the rate density for in situ BBHs ∼0.01–0.1 yr−1 Gpc−3, indicating that the ex situ formation channel may be as important as the in situ one for producing GW events. We also evaluate the detectability of our simulated GW events for selected planned GW instruments, such as the Einstein Telescope (ET). For instance, we find the all-sky detection rate with signal-to-noise ratios above 10 to be ${\lesssim} 100\, \rm {yr^{-1}}$ for the xylophone configuration of ET. However, our results are highly sensitive to the subgrid models for BBH identification and evolution, such that the GW event efficiency (rate) is reduced by a factor of 4 (20) in the pessimistic case. The ex situ channel of Pop III BBHs deserves further investigation with better modelling of the environments around Pop III-seeded BHs.

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Post-merger chirps from binary black holes as probes of the final black-hole horizon

Communications Physics ◽

10.1038/s42005-020-00446-7 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Juan Calderon Bustillo ◽

Christopher Evans ◽

James A. Clark ◽

Grace Kim ◽

Pablo Laguna ◽

...

Keyword(s):

Black Hole ◽

Gravitational Waves ◽

Apparent Horizon ◽

Future Generation ◽

Black Hole Horizon ◽

Binary Black Holes ◽

Binary Black Hole ◽

Einstein Telescope ◽

Geometrical Features ◽

Observable Feature

Abstract The merger of a binary black hole gives birth to a highly distorted final black hole. The gravitational radiation emitted as this black hole relaxes presents us with the unique opportunity to probe extreme gravity and its connection with the dynamics of the black hole horizon. Using numerical relativity simulations, we demonstrate a connection between a concrete observable feature in the gravitational waves and geometrical features on the dynamical apparent horizon of the final black hole. Specifically, we show how the line-of-sight passage of a “cusp”-like defect on the horizon of the final black hole correlates with “chirp”-like frequency peaks in the post-merger gravitational-waves. These post-merger chirps should be observed and analyzed as the sensitivity of LIGO and Virgo increase and as future generation detectors, such as LISA and the Einstein Telescope, become operational.

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