PREDICTING THE DIRECTION OF THE FINAL SPIN FROM THE COALESCENCE OF TWO BLACK HOLES

By E. Barausse, Luciano Rezzolla. 2007

210 citations recorded by the source corpus.

Knowledge of the spin of the black hole resulting from the merger of a generic black-hole binary is of great importance for studying the cosmological evolution of supermassive black holes. Several attempts have been made to model the spin via simple expressions exploiting the results of numerical-relativity simulations. While these expressions are in reasonable agreement with the simulations, they neglect the precession of the binary's orbital plane, and cannot therefore be applied directly—i.e., without evolving the system to small separations using post-Newtonian theory—to binaries with separations larger than a few hundred gravitational radii. While not a problem in principle, this may be impractical if the formulas are employed in cosmological merger trees or N-body simulations, which provide the spins and angular momentum of the two black holes when their separation is of hundreds or thousands of gravitational radii. The formula that we propose is instead built on improved assumptions and gives, for any separation, a very accurate prediction both for the norm of the final spin and for its direction. By comparing with the numerical data, we also show that the final-spin direction is very accurately aligned with the binary's total angular momentum at large separation. Hence, observations of the final-spin direction (e.g., via a jet) can provide information on the binary's orbital plane at large separations and could be relevant, for instance, for studying X-shaped radio sources.

Subfields: Astronomy and Astrophysics, Ocean Engineering

View Paper: https://www.semanticscholar.org/paper/0a2b056844dac4b7bb3bc598a9b001c6ece97fef

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Ocean Engineering

Citations in the corpus

Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime (2012, background): “Measurements of the individual masses and spins will allow us to predict the mass and the spin of the remnant black hole (Rezzolla et al., 2008b), which can be directly tested against the corresponding parameters extracted from the ringdown.”
Black-hole binaries, gravitational waves, and numerical relativity (2010, background): “Barausse and Rezzolla (2009) proposed a different expression for generic binaries, using a set of assumptions about the approximate conservation of the magnitudes and relative angles of certain angular momentum vectors.”
Black hole growth through hierarchical black hole mergers in dense star clusters: implications for gravitational wave detections (2018, background): “In this case, the remnant remains in the cluster, we sum the masses of the two BHs and estimate the spin of the remnant following the prescriptions in Rezzolla et al. (2008).”
Galacticus: A Semi-Analytic Model of Galaxy Formation (2010, methodology): “Rezzolla et al. (2008): This method uses the fitting function of Rezzolla et al.”
One Channel to Rule Them All? Constraining the Origins of Binary Black Holes Using Multiple Formation Pathways (2020, methodology): “If the merger remnant is retained inside the cluster we compute its spin and mass using the prescriptions in Rezzolla et al. (2008).”
Black hole evolution – I. Supernova-regulated black hole growth (2015, methodology): “Finally, we update BH spins after BH–BH coalescences using the analytical fit of Rezzolla et al. (2008) derived from relativistic numerical simulations of BH binaries.”