Testing the Black-Hole Area Law with GW150914

Area of Science:

• Gravitational-wave astrophysics
• General Relativity
• Black hole physics

Background:

• Hawking's black-hole area theorem is a fundamental concept in black hole thermodynamics.
• The theorem states that the surface area of a black hole can never decrease.
• Observational confirmation requires precise measurements of black hole mergers.

Purpose of the Study:

• To provide observational evidence supporting Hawking's black-hole area theorem.
• To analyze the ringdown phase of a black hole merger using gravitational wave data.
• To test the consistency of the remnant black hole's properties with general relativity.

Main Methods:

• Analysis of the first detected gravitational wave signal, GW150914, from a black hole merger.
• A novel time-domain analysis of pre-merger and post-merger gravitational wave data.
• Modeling the ringdown signal, including quadrupolar mode overtones.

Main Results:

• Observational confirmation of Hawking's black-hole area theorem with 97% probability (including overtones).
• Agreement with the theorem's prediction with 95% probability (excluding overtones).
• The inspiral and ringdown phases indicate a consistent remnant mass and spin.

Conclusions:

• The study provides strong observational support for Hawking's black-hole area theorem.
• The results are consistent with the predictions of general relativity.
• This analysis demonstrates the power of gravitational wave astronomy in testing fundamental physics.