Measuring the mass and distance of a gravitational wave (GW) source is a fundamental problem in GW astronomy. The issue is becoming even more pressing since LIGO and Virgo have detected massive black holes that in the past were thought to be rare, if not entirely impossible. The waveform templates used in the detection are developed under the assumption that the sources are residing in a...
Waveform models are important to gravitational wave data analysis. People recently pay much attention to the waveform model construction for eccentric binary black hole coalescence. Several Effective-One-Body Numerical-Relativity waveform models of eccentric binary black hole coalescence have been constructed. But none of them can treat orbit eccentricity and spin-precessing simultaneously....
In this talk, I will introduce the binary-extreme-mass-ratio inspirals(b-EMRIs) which the whole compact binary captured by a supermassive black hole. B-EMRIs are multi-band gravitational wave sources both for space-borne and ground-base detectors. I will explain how we accurately calculate the waveforms, how to identify EMRI signals by the deep learning. Finally I will discuss the sciences...
Besides canonical GRBs and kilonovae, neutron star mergers may be accompanied by different electromagnetic counterparts including: (1) precursors, (2) repeating outbursts from the merger product before its collapse into a black hole, and (3) unusual late GRB if the collapse is delayed by days. Physical mechanisms for the pre-merger and post-merger bursts will be discussed. Their detection...
While the LIGO/VIRGO/KAGRA (LVK) collaboration has observed $\sim 100$ binary black hole (BBH) mergers to date, the formation mechanisms of these BBHs remains poorly understood. The most promising approach to discriminating among the many proposed mechanisms relies on comparison of theoretical models to population-level statistics of the observed BBH events. However, the constraints derived...
The possibility of binary black hole (BH) mergers in the accretion disks around active galactic nuclei (AGN) has recently received much attention. Studying the formation processes of these binaries allows us to more reasonably predict the rate and the observational properties of their mergers. In this talk, I will present our works on the mechanisms of forming tightly bound BH binaries in AGN...
This talk reviews recent developments related to simulations of neutron-star mergers, the generation of kilonovae, and the synthesis of rapid neutron capture (r-process) elements in the Universe. In particular, the talk will discuss recent constraints on r-process nucleosynthesis from the O3 run of the LVK gravitational-wave detectors. It will also focus on recently identified...
On August 17, 2017, GW170817 showed the merger of a double neutron star system. Model-independent data analysis by butterfly-matched filtering, a novel time-symmetric data analysis method with sensitivity on par with CBC, reveals a continuation in GW170817B starting 0.92±0.08 s after final coalescence. It signals the birth of the central engine of GRB170817A significant at 5.5 σ (van Putten &...
The detection of gravitational wave events has stimulated theoretical modeling of the formation and evolution of double compact objects (DCOs). However, even for the most studied isolated binary evolution channel, there exist large uncertainties in the input parameters and treatments of the binary evolution process. So far, double neutron stars (DNSs) are the only DCOs for which direct...
The origin of stellar black hole binary (sBHB) mergers detected by the LIGO/Virgo interferometers is debated. One viable channel is the formation and merger of sBHB in the accretion discs surrounding active supermassive black holes. In this talk, i will review our observational strategy to investigate and assess a spatial correlation between Gravitational Wave detections and Active Galactic...
Since the first discovery of a transient gravitational-wave signal by LIGO/Virgo, it has motivated many theoretical studies on how merging binary black holes (BBHs) form. Active galactic nucleus (AGN) disks have been proposed as promising locations for producing some of gravitational wave events. However, the validity of this AGN disk channel remains largely debatable due to the complexity of...
Quasi-periodic eruptions (QPEs) are intense repeating soft X-ray bursts with recurrence times about a few hours from nearby galactic nuclei. The origin of QPEs is still unclear. Though many models have been proposed for explaining the QPE observations, most of them can only recover
a portion of diverse features of different QPEs. In this work, we revised the extreme mass ratio inspiral...
In this talk I will discuss one of the primary targets of space-borne gravitational wave detectors – the Extreme Mass Ratio Inspirals, which usually comprises a massive black hole and a stellar-mass companion. In recent years there are significant progress in terms of its formation channel, rate estimation and dynamics in astrophysical environments. I will review these new developments and...
The LIGO experiment has detected mergers between stellar-mass black
holes, and pulsar timing arrays on the ground have discovered a
stochastic background of gravitational waves attributable to merging
massive black hole binaries. The LISA satellites, planned in space in
the mid 2030s, are expected to detect gravitational waves (GWs) from
individual massive black hole binaries at high...
The GW190521 event – an 85 Msun and a 66 Msun black hole (BH) coalescing to a 142 Msun BH – the heaviest binary black hole (BBH) merger to date has opened up new discussions on the formation channels of BBHs as possible LIGO sources. In this talk, we focus on the scenario where BBHs are embedded inside an AGN disk (disk around a supermassive black hole at the center of a galaxy). We will...
Bosonic particles within a suitable mass range may form clouds around rotating black holes through the black hole superradiance process. For black holes in binary black hole systems, it has been suggested that these clouds are mostly depleted at large binary separations because of a resonant level mixing effect, and hence may not be dynamically relevant for black hole and neutron star binaries...
The upcoming Laser Interferometer Space Antenna (LISA) is expected to detect gravitational waves (GWs) from massive black hole binaries (MBHB). Finding the electromagnetic (EM) counterparts for these GW events will be crucial for understanding how and where MBHBs merge, measuring their redshifts, constraining the Hubble constant and the graviton mass, and for other novel science applications....
Gravitational waves (GWs) in the millihertz bands provide are great tools for understanding the cosmological evolution of supermassive black holes (SMBHs) in galactic nuclei. SMBH binaries in high-redshift quasars are expected to be the primarily target of individually identified GW sources. Previous studies mainly considered specific BH seeding models and limited mass ranges in estimating the...
We study the dynamics of a solar-type star orbiting around a black hole binary (BHB) in a nearly coplanar system. We present a novel effect that can prompt a growth and significant oscillations of the eccentricity of the stellar orbit when the system encounters an “apsidal precession resonance,” where the apsidal precession rate of the outer stellar orbit matches that of the inner BHB. The...
A major outstanding challenge is how to observationally infer the formation of black hole mergers using gravitational waves alone. I will discuss and show how several likely formation channels will give rise to modulations of the gravitational wave signal, which can be modeled and looked for with current (LIGO/Virgo) and future (3G) ground-based observatories. Modulations of the gravitational...
I will review upcoming survey facilities for electromagnetic observations of dual (~kpc) and binary (~sub-pc) SMBHs. I will highlight the combined power of Rubin, Euclid, and Roman in exploring the unexplored parameter space that is particularly important for multi-messenger astronomy.
Gravitational lensing of gravitational waves is one kind of important phenomena that the current and future gravitational wave experiments are going to discover. The gravitational lensing of gravitational waves is expected to provide a unique probe to not only the nature of gravitational waves but also the nature of dark matter and cosmology. In this talk, we will briefly summarize the...
I will talk about a tight universal relation between the shape eccentricity and the moment of inertia for rotating neutron stars that we discovered recently.
Pulsar Timing Arrays (PTAs) search for nHz gravitational waves by timing the radio signals from a network of stable millisecond pulsars and looking for a spatially correlated common signal in the data set. We expect to find a gravitational wave background (GWB) first, followed by possible individual sources. PTAs have reported the finding of evidence for such a GWB signal in various data sets,...
The detection of gravitational waves from the LIGO/Virgo collaboration provides an excellent probe for the fundamental physics of gravity, and the recent pulsar timing arrays (PTA) detections of stochastic gravitational wave background (SGWB) open a new window due to their different frequency sensitivity (nHz band). We explore the possibility of testing gravity using PTA signals by studying...
In this talk, I will review the high-latency search efforts for compact binary coalescence in gravitational wave data.
I will review the current pipelines, their progress in the last couple of years, and the efforts to improve them.
I will emphasize the current gaps in our searches, emphasizing the open algorithmic questions that must be solved to answer the pressing physical questions.
I...
