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Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE,General Relativity and Quantum Cosmology, gr-qc
Abstract:
The final black hole left behind after a binary black hole merger can attain
a recoil velocity, or a "kick", reaching values up to 5000 km/s. This
phenomenon has important implications for gravitational wave astronomy, black
hole formation scenarios, testing general relativity, and galaxy evolution. We
consider the gravitational wave signal from the binary black hole merger
GW200129_065458 (henceforth referred to as GW200129), which has been shown to
exhibit strong evidence of orbital precession. Using numerical relativity
surrogate models, we constrain the kick velocity of GW200129 to $v_f \sim
1542^{+747}_{-1098}$ km/s or $v_f \gtrsim 698$ km/s (one-sided limit), at 90\%
credibility. This marks the first identification of a large kick velocity for
an individual gravitational wave event. Given the kick velocity of GW200129, we
estimate that there is a less than $0.48\%$ ($7.7\%$) probability that the
remnant black hole after the merger would be retained by globular (nuclear
star) clusters. Finally, we show that kick effects are not expected to cause
biases in ringdown tests of general relativity for this event, although this
may change in the future with improved detectors.
