# Weighing The Black Holes Of GW150914

## TL;DR

This paper estimates the masses of the black holes in GW150914 at their event horizons using a quasi-local energy approach, revealing higher horizon masses than asymptotic values and inferring the progenitor star masses.

## Contribution

It introduces a method to evaluate black hole masses at their horizons and estimates the progenitor star masses from these horizon measurements.

## Key findings

- Horizon masses are significantly higher than asymptotic masses.
- Progenitor stars had masses of approximately 95 and 76 solar masses.
- The approach explains gravitational wave emission through horizon mass considerations.

## Abstract

We evaluate the mass of the black holes of GW150914 at their event horizons via quasi-local energy approach and obtain the values of 71 and 57 solar masses, compared to their asymptotic values of 36 and 29 units, respectively, as reported by LIGO. A higher mass at the event horizon is compulsory in order to overcome the huge negative gravitational potential energy surrounding the black holes and allow for the emission of gravitational waves during merging. We estimate the initial mass of the stars which collapsed to form the black holes from the horizon mass and obtain the impressive values of 95 and 76 solar masses for these progenitor stars.