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Wenshuai Liu

Publications and source records attributed to Wenshuai Liu.

24 records · Page 2Linked to original sources
arXiv2022

Imprint of primordial gravitational wave with extremely low frequency on gravitational lens system

Primordial gravitational waves with extremely low frequency are expected to origin from inflation in the early Universe. The detection of such kind of gravitational waves is of great significance to verify the inflationary theory and determine the energy scale of inflation. B-mode of polarization of cosmic microwave background shows to be a promising probe of extremely low frequency primordial gravitational wave. In order to find a complementary observational feature induced by primordial gravitational wave with extremely low frequency, we propose an alternative way of detection by investigating the effect of primordial gravitational wave with extremely low frequency on a gravitational lens system with a non-aligned source-deflector-observer configuration. The results show that, with a series of chosen parameters, gravitational lens system with perturbation from extremely low frequency primordial gravitational wave could induce time delay which could deviate from the time delay deduced from theoretical model as much as about one hundred percent, meaning that gravitational lens system with a non-aligned configuration could serve as a potential long-base-line detector of extremely low frequency primordial gravitational wave.

astro-ph.CO↗
arXiv2022

Energy Extraction via Magnetic Reconnection in the Ergosphere of a rotating non-Kerr Black Hole

Magnetic reconnection process in the ergosphere is investigated for a relativistic plasma around a rotating non-Kerr black hole. For a rotating non-Kerr black hole immersed in magnetic field generated by an externally material, anti-parallel magnetic field line could form in the ergosphere due to the frame dragging. Therefore, magnetic reconnection could occur in the ergosphere. Such magnetic reconnection may generate negative energy at infinity by redistributing the angular momentum during the process. The results show that, with the effect of the deformed parameter, extraction of energy from a rotating non-Kerr black hole by magnetic reconnection could be enhanced in the presence of a positive deformed parameter.

astro-ph.HE↗
arXiv2021

Detection of extremely low frequency gravitational wave using gravitational lens: The general case

The effect of gravitational wave of extremely low frequency on time delays between different locations on the Einstein ring in a lens system with an aligned source-deflector-observer configuration is investigated. The observer will observe an Einstein ring from the lens system aligned in a highly symmetric configuration. Time delays between different locations on the Einstein ring cannot emerge without gravitational wave of cosmological wavelength propagating through the lens system. Otherwise, different locations on the Einstein ring will show time delays. Our previous studies showed that time delays from different locations on the Einstein ring in the presence of gravitational wave of cosmological wavelength present a special relationship. But this result is limited to a specific aligned source-deflector-observer configuration where the source and the observer are equidistant from the deflector and the gravitational wave has special direction of propagation and polarization. In order to investigate the property in the general case, we extend to the general condition that the source and the observer aren't equidistant from the deflector and the direction and polarization of the gravitational wave is arbitrary in the present work. Results in this work show that time delays between different locations on the Einstein ring with the general condition present the same relationship as that in our previous studies.

gr-qc↗
arXiv2021

Evolution of circumbinary accretion disk around supermassive binary black hole: post-Newtonian hydrodynamics versus Newtonian hydrodynamics

We study the evolution of accretion disk around a supermassive binary black hole with equal mass using non-relativistic hydrodynamical simulations performed with FARGO3D. Compared with previous studies with the Newtonian hydrodynamics, here, we adopt the post-Newtonian hydrodynamics using the near zone metric of the binary black hole. In contrast to the Newtonian investigation, we find that there is a dramatic difference in the post-Newtonian regime, gap formed by the circumbinary accretion disk around the binary with equal mass is wider with the post-Newtonian hydrodynamics than that with the Newtonian hydrodynamics and is independent of disk viscosity given that hydrodynamical simulations are run for about the same factor times the viscous timescale associated with different viscosities. This may present unique observable signatures of the continuum emission in such binary-disk system.

astro-ph.HE↗
arXiv2021

Detection of extremely low frequency gravitational wave using gravitational lens

The effect of gravitational wave of cosmological wavelength on the gravitational lensing is investigated. When the source, deflector, and observer are aligned in a highly symmetric configuration, an Einstein ring will be observed by the observer. There will be no time delays between different locations on the Einstein ring in the absence of gravitational wave. Otherwise, time delays between different locations on the Einstein ring will emerge if cosmological gravitational wave propagates through the system. Previous studies demonstrated that the time delay resulting from the aligned source-deflector-observer configuration in the presence of gravitational wave of cosmological wavelength could be equivalent to that of a similar lens with a nonaligned source-deflector-observer configuration in the absence of gravitational wave. Results in this work show that gravitational lens with the aligned source-deflector-observer configuration could serve as a potential gravitational wave detector when the whole Einstein ring observed by the observer is taken into account.

gr-qc↗