How fast do black holes travel
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How Fast Do Black Holes Travel?
Recoil Velocities in Binary Black Hole Mergers
Kick Velocities in Nonspinning and Spinning Binaries
When two black holes merge, they can experience a recoil velocity, often referred to as a "kick," due to asymmetries in the emitted gravitational waves. For nonspinning binary black holes, the kick velocities are generally around a few hundred kilometers per second (km/s) . However, when the black holes have spins, especially when these spins are antialigned with the orbital plane, the kick velocities can be significantly higher. For instance, kick velocities of up to 500 km/s have been observed in spinning configurations .
Maximum Recoil Velocities
Recent studies have pushed the boundaries of these velocities even further. For equal-mass binaries with antialigned spins in the orbital plane, kick velocities can reach up to 2500 km/s González2007Bruegmann2007. This is a substantial increase and has significant implications for our understanding of black hole formation and the dynamics within galaxies.
Extreme Cases and Superkicks
In some extreme cases, such as the merger of black holes with highly specific spin orientations and configurations, the recoil velocities can be even more dramatic. For example, simulations have shown that velocities can reach up to 5000 km/s in certain scenarios . Moreover, the concept of "superkicks" has been explored, where the recoil velocity can be as high as 28,562 km/s, which is approximately 10% of the speed of light . These superkicks occur under very specific conditions, such as equal mass binaries with opposite spins aligned along their orbital plane.
Observational Evidence and Implications
Gravitational Wave Signals
The detection of gravitational waves from black hole mergers, such as the event GW200129, has provided strong evidence for large kick velocities. The kick velocity for this particular event was constrained to be around 1542 km/s, with a possible range extending up to 5000 km/s . This marks a significant milestone in gravitational wave astronomy and helps in testing general relativity and understanding galaxy evolution.
Black Hole Birth Kicks
Apart from merger-induced kicks, black holes can also receive natal kicks during their formation from supernovae. Observations of low-mass X-ray binaries suggest that these birth kicks are generally lower, around 100 km/s, although higher velocities are not entirely ruled out .
Conclusion
Black holes can travel at incredibly high speeds, especially following mergers. While nonspinning binaries typically result in kicks of a few hundred km/s, spinning configurations can lead to much higher velocities, with extreme cases reaching up to 28,562 km/s. These findings have profound implications for our understanding of black hole dynamics, galaxy formation, and the fundamental physics governing these cosmic giants.
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Supermassive recoil velocities for binary black-hole mergers with antialigned spins.
Supermassive recoil velocities of at least 2500 km/s are possible for equal-mass binaries with antialigned spins in binary black-hole mergers, potentially impacting models of black-hole formation and host galaxy structures.
Light speed rotating black holes: The special holes
The universe may be a growing and light speed rotating primordial black hole, with each galaxy containing a central fast growing and fast spinning black hole, and the present Hubble's constant may be a result of this growing and light speed rotating primordial black hole.
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