Black Hole Spectroscopy with Coherent Mode Stacking

Area of Science:

• Astrophysics
• Gravitational-wave astronomy
• General relativity

Background:

• Binary black hole mergers produce gravitational waves containing ringdown modes.
• Measuring these modes tests fundamental black hole properties and modified gravity theories.
• Advanced LIGO/Virgo require enhanced methods for precise ringdown mode detection.

Purpose of the Study:

• To propose and validate a coherent mode stacking method for gravitational wave ringdown signals.
• To improve the detection capabilities for specific ringdown modes in binary black hole mergers.

Main Methods:

• A coherent mode stacking technique is proposed, involving signal rescaling and constructive summation.
• A priori information from the inspiral-merger phase is used for coherent superposition.
• Simulated binary black hole merger events targeting the ℓ=m=3 ringdown mode were analyzed.

Main Results:

• The coherent mode stacking method significantly boosts the signal-to-noise ratio for the targeted ringdown mode.
• The collective target mode's detectability is enhanced compared to single-event analysis.
• Advanced-era detectors are predicted to measure this collective mode within one year of data at design sensitivity.

Conclusions:

• The proposed coherent mode stacking method offers a significant advancement for gravitational wave data analysis.
• This technique will enhance the ability of current and future detectors to test fundamental physics.
• Enhanced measurement of ringdown modes will provide crucial insights into black hole physics and gravity.