arXiv subjects

Wen-Hong Ruan

Publications and source records attributed to Wen-Hong Ruan.

12 recordsLinked to original sources

arXiv2026

Inspiral waveforms of charged compact binaries and observational constraints

Electric charges carried by compact objects can affect binary dynamics and imprint characteristic signatures on gravitational-wave signals. We derive next-to-leading-order post-Newtonian frequency-domain waveforms for charged compact binaries in both the gravitational-quadrupole and electric-dipole dominated regimes, including electromagnetic corrections beyond leading-order electric-dipole radiation that reduce the degeneracy between the component charge-to-mass ratios. Using gravitational wave events from GWTC-5.0, we place constraints on the charge-to-mass ratio and mass of each component of the binary system.

gr-qc↗

arXiv2024

Premerger detection of massive black hole binaries using deep learning

Coalescing massive black hole binaries (MBHBs) are one of primary sources for space-based gravitational wave (GW) observations. The mergers of these binaries are expected to give rise to detectable electromagnetic (EM) emissions with a narrow time window. The premerger detection of GW signals is vital for follow-up EM observations. The conventional approach for searching GW signals involves high computational costs. In this study, we present a deep learning model to search for GW signals from MBHBs. Our model is able to process 4.7 days of simulated data within 0.01 seconds and detect GW signals several hours to days before the final merger. The model provides the possibility of the coincident GW and EM detection of MBHBs.

astro-ph.IM↗

arXiv2023

Parameter inference for coalescing massive black hole binaries using deep learning

In the 2030s, a new era of gravitational-wave (GW) observations will dawn as multiple space-based GW detectors, such as the Laser Interferometer Space Antenna, Taiji and TianQin, open the millihertz window for GW astronomy. These detectors are poised to detect a multitude of GW signals emitted by different sources. It is a challenging task for GW data analysis to recover the parameters of these sources at a low computational cost. Generally, the matched filtering approach entails exploring an extensive parameter space for all resolvable sources, incurring a substantial cost owing to the generation of GW waveform templates. To alleviate the challenge, we make an attempt to perform parameter inference for coalescing massive black hole binaries (MBHBs) using deep learning. The model trained in this work has the capability to produce 50,000 posterior samples for redshifted total mass, mass ratio, coalescence time and luminosity distance of a MBHB in about twenty seconds. Our model can serve as a potent data pre-processing tool, reducing the volume of parameter space by more than four orders of magnitude for MBHB signals with a signal-to-noise ratio larger than 100. Moreover, the model exhibits robustness when handling input data that contains multiple MBHB signals.

astro-ph.IM↗

arXiv2023

On networks of space-based gravitational-wave detectors

The space-based laser interferometers, LISA, Taiji and TianQin, are targeting to observe milliHz gravitational waves (GWs) in the 2030s. The joint observations from multiple space-based detectors yield significant advantages. In this work, we recap the studies and investigations for the joint space-based GW detector networks to highlight: 1) the high precision of sky localization for the massive binary black hole (BBH) coalescences and the GW sirens in the cosmological implication, 2) the effectiveness to test the parity violation in the stochastic GW background observations, 3) the efficiency of subtracting galactic foreground, 4) the improvement in stellar-mass BBH observations. We inspect alternative networks by trading off massive BBH observations and stochastic GW background observation.

gr-qc↗

arXiv2023

Rapid search for massive black hole binary coalescences using deep learning

The coalescences of massive black hole binaries are one of the main targets of space-based gravitational wave observatories. Such gravitational wave sources are expected to be accompanied by electromagnetic emissions. Low latency detection of the massive black hole mergers provides a start point for a global-fit analysis to explore the large parameter space of signals simultaneously being present in the data but at great computational cost. To alleviate this issue, we present a deep learning method for rapidly searching for signals of massive black hole binaries in gravitational wave data. Our model is capable of processing a year of data, simulated from the LISA data challenge, in only several seconds, while identifying all coalescences of massive black hole binaries with no false alarms. We further demonstrate that the model shows robust resistance to a wide range of generalization cases, including various waveform families and updated instrumental configurations. This method offers an effective approach that combines advances in artificial intelligence to open a new pathway for space-based gravitational wave observations.

astro-ph.IM↗

arXiv2023

Confusion noise from Galactic binaries for Taiji

Gravitational waves (GWs) from tens of millions of compact binaries in our Milky Way enter the milli-Hertz band of space-based detection. The majority of them cannot be resolved individually, resulting in a foreground confusion noise for Laser Interferometer Space Antenna (LISA). The concept of Taiji mission is similar to LISA's with slightly better sensitivity, which means that the galactic GW signals will also affect the detection with Taiji. Here we generate the GW signals from 29.8 million galactic binaries for Taiji and subtract the `resolvable' sources. The confusion noise is estimated and fitted in an analytic form with 6-month, 1-year, 2-year and 4-year observation time. We find that the full sensitivity curve is slightly lower for Taiji than for LISA at frequencies of $\leq 0.8$ mHz and around 2~mHz. For a 4-year lifetime, more than 29 thousand sources are resolvable with Taiji. Compared to LISA, Taiji can subtract $\sim 20 \%$ more sources and the distribution of them in our Milky Way is consistent with that of the resolvable sources with LISA. At frequencies around 2~mHz or with the chirp masses ranging from $0.2 M_\odot$ to $0.4 M_\odot$, more sources become resolvable with Taiji.

astro-ph.IM↗

arXiv2021

Gravitational and electromagnetic radiation from binary black holes with electric and magnetic charges: Elliptical orbits on a cone

Extending the electromagnetic and gravitational radiations from binary black holes with electric and magnetic charges in circular orbits in Phys. Rev. D {\bf 102}, 103520 (2020), we calculate the total emission rates of energy and angular momentum due to gravitational and electromagnetic radiations from dyonic binary black holes in precessing elliptical orbits. It is shown that the emission rates of energy and angular momentum due to gravitational and electromagnetic radiations have the same dependence on the conic angle for different orbits. Moreover, we obtain the evolutions of orbits and find that a circular orbit remains circular while an elliptic orbit becomes quasi-circular due to electromagnetic and gravitational radiations. Using the evolution of orbits, we derive the waveform models for dyonic binary black hole inspirals and show the amplitudes of the gravitational waves for dyonic binary black hole inspirals differ from those for Schwarzschild binary black hole inspirals, which can be used to test electric and magnetic charges of black holes.

gr-qc↗

arXiv2021

Hubble parameter estimation via dark sirens with the LISA-Taiji network

The Hubble parameter is one of the central parameters in modern cosmology, which describes the present expansion rate of the universe. Their values inferred from the late-time observations are systematically higher than those from the early-time measurements by about $10\%$. To come to a robust conclusion, independent probes with accuracy at percent levels are crucial. Gravitational waves from compact binary coalescence events can be formulated into the standard siren approach to provide an independent Hubble parameter measurement. The future space-borne gravitational wave observatory network, such as the LISA-Taiji network, will be able to measure the gravitational wave signals in the Millihertz bands with unprecedented accuracy. By including several statistical and instrumental noises, we show that within 5 years operation time, the LISA-Taiji network is able to constrain the Hubble parameter within $1\%$ accuracy, and possibly beats the scatters down to $0.5\%$ or even better.

astro-ph.CO↗

arXiv2020

Constraining gravitational-wave polarizations with Taiji

Space-based gravitational-wave detectors consist of a triangle of three spacecraft, which makes it possible to detect polarization modes of gravitational waves due to the motion of the detectors in space. In this paper we explore the ability of Taiji to detect the polarization modes in the parametrized post-Einsteinian framework. Assuming massive black hole binaries with the total mass of $M=4\times10^5\,M_{\odot}$ at redshift of $z=1$, we find that Taiji can measure the dipole and quadruple emission ($Δα_D/α_D$ and $Δα_Q/α_Q$) with the accuracy of up to $\sim 0.04\%$, with the fiducial value of $α_D=0.001$, the scalar transverse and longitudinal modes ($Δα_B$ and $Δα_L$) up to $\sim 0.01$, and the vector modes ($Δα_V$) up to $\sim 0.0005$.

gr-qc↗

arXiv2020

Taiji Program: Gravitational-Wave Sources

We review potential low-frequency gravitational-wave sources, which are expected to be detected by Taiji, a Chinese space-based gravitational-wave detector, estimate the detection rates of these gravitational-wave sources and present the parameter estimation of massive black hole binaries.

gr-qc↗

arXiv2020

The LISA-Taiji network

Both LISA and Taiji, planned space-based gravitational-wave detectors in orbit around the Sun, are expected to launch in 2030-2035. Assuming a one-year overlap, we explore a potential LISA-Taiji network to fast and accurately localize the gravitational-wave sources.

gr-qc↗

arXiv2019

The LISA-Taiji network: precision localization of massive black hole binaries

A space-based gravitational-wave detector, LISA, consists of a triangle of three spacecrafts with a separation distance of 2.5 million kilometers in a heliocentric orbit behind the Earth. Like LISA, Taiji is compose of a triangle of three spacecrafts with a separation distance of 3 million kilometers in a heliocentric orbit ahead of the Earth. They are expected to launch in 2030-2035. Assuming a one-year overlap, we propose the LISA-Taiji network in space to fast and accurately localize the gravitational-wave sources. We use the Fisher information matrix approach to analyze the sky localization for coalescing massive black hole binaries. For an equal-mass black hole binary located at redshift of 1 with a total intrinsic mass of $10^5 M_{\odot}$, the LISA-Taiji network may achieves about four orders of magnitude improvement on the event localization region compared to an individual detector. The precision measurement of sky location from the gravitational-wave signal may completely identify the host galaxy with low redshifts prior to the final black hole merger. Such the identification of the host galaxy is helpful for the follow-up change in electromagnetic emissions of the accretion disk when the massive black hole binary merges to a single massive black hole, and enables the coalescing massive black hole binaries to be used as a standard siren.

gr-qc↗