Related papers: Binary Black Holes in Stationary Orbits
Binary systems emit gravitational waves in a well-known pattern; for binaries in circular orbits, the emitted radiation has a frequency that is twice the orbital frequency. Systems in eccentric orbits, however, emit gravitational radiation…
Modeling the stochastic gravitational wave background from various astrophysical sources is a key objective in view of upcoming observations with ground- and space-based gravitational wave observatories such as Advanced LIGO, VIRGO, eLISA…
Recent gravitational wave observations include possible detections of black hole - neutron star binary mergers. As with binary black hole mergers, numerical simulations help characterize the sources. For binary systems with neutron star…
Cosmological observations over past couple of decades favor our universe with a tiny positive cosmological constant. Presence of cosmological constant not only imposes theoretical challenges in gravitational wave physics, it has also…
Merging compact black-hole (BH) binaries are likely to exist in the nuclear star clusters around supermassive BHs (SMBHs), such as Sgr A$^\ast$. They may also form in the accretion disks of active galactic nuclei. Such compact binaries can…
We explore spinning, precessing, unequal mass binary black holes to display the long term orbital angular momentum, $\vec{L}$, flip dynamics. We study two prototypical cases of binaries with mass ratios $q=1/7$ and $q=1/15$ and a misaligned…
Black holes in binary star systems are vital for understanding the process of pr oducing gravitational wave sources, understanding how supernovae work, and for p roviding fossil evidence for the high mass stars from earlier in the Universe.…
Stellar companion of a black hole orbiting in an eccentric orbit will experience modulating tidal force with a periodicity same as that of the orbital period. This, in turn, would modulate accretion rates, and the seed photon flux which are…
Galaxy mergers produce supermassive black hole binaries, which emit gravitational waves prior to their coalescence. We perform three-dimensional hydrodynamic simulations to study the tidal disruption of stars by such a binary in the final…
The majority of fast millisecond pulsars are in binary systems, so that any periodic signal they emit is modulated by both Doppler and relativistic effects. Here we show how well-established binary models can be used to account for these…
It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole…
We review the recent multifrequency studies of galactic black hole binaries, aiming at revealing the underlying emission processes and physical properties in these systems. The optical and infrared observations are important for determining…
Compact binary coalescences are the most promising sources of gravitational waves (GWs) for ground based detectors. Binary systems containing one or two spinning black holes are particularly interesting due to spin-orbit (and eventual…
Zoom-whirl behavior has the reputation of being a rare phenomenon. The concern has been that gravitational radiation would drain angular momentum so rapidly that generic orbits would circularize before zoom-whirl behavior could play out,…
Accretion discs around black holes in X-ray binary stars are warped if the spin axis of the black hole is not perpendicular to the binary orbital plane. They can also become eccentric through an instability involving a resonance with the…
We discuss a cornucopia of potential astrophysical signatures and constraints on magnetically charged black holes of various masses. As recently highlighted, being potentially viable astrophysical candidates with immense electromagnetic…
We describe early success in the evolution of binary black hole spacetimes with a numerical code based on a generalization of harmonic coordinates. Indications are that with sufficient resolution this scheme is capable of evolving binary…
We perform fully relativistic calculations of binary neutron stars in corotating, circular orbit. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, causing the system to…
The localization of stellar-mass binary black hole mergers using gravitational waves is critical in understanding the properties of the binaries' host galaxies, observing possible electromagnetic emission from the mergers, or using them as…
Several models of physics beyond the Standard Model predict the existence of new ultralight bosons. This thesis investigates a way to discover such particles through observations of gravitational waves from binary black holes. This is…