What can we really infer from GW 150914? (II)

TL;DR

This paper critically examines GW 150914, demonstrating that basic textbook formulas can estimate black-hole merger parameters without complex simulations, but emphasizes the need for independent observational constraints for accurate astrophysical inferences.

Contribution

It shows that simple, well-known formulas can be used to estimate black-hole merger parameters from gravitational-wave data, challenging reliance on complex simulations.

Findings

Basic formulas can estimate system parameters accurately.

LIGO data alone may not fully constrain astrophysical properties.

Independent observational constraints are necessary for reliable inferences.

Abstract

In a recent letter we have outlined some issues on GW 150914, we hereby give additional details. We analyze the event GW 150914 announced by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) as the gravitational-wave emission of a black-hole binary merger. We show that the parameters of the coalescing system and of the newly formed Kerr black-hole can be extracted from basic results of the gravitational-wave emission during the inspiraling and merger phases without sophisticate numerical simulations. Our strikingly accurate estimates are based on textbook formulas describing two different regimes: 1) the binary inspiraling analysis treated in Landau and Lifshitz textbook, 2) the plunge of a particle into a black-hole, treated in the Rees-Ruffini-Wheeler textbook as well as 3) the transition between these two regimes following Detweiler's treatment of a particle infalling with non-zero angular momentum onto a black-hole. It is stressed that in order to infer any astrophysical information on the masses of the system both regimes have to be independently and observationally constrained by LIGO, which does not appear to be the case.