Detecting and Denoising Gravitational Wave Signals from Binary Black Holes using Deep Learning

TL;DR

This paper introduces a deep learning convolutional neural network that detects and denoises gravitational wave signals from black hole mergers faster than traditional methods, capable of handling unmodeled signals and revealing new features.

Contribution

It presents the first machine learning approach using 2D time-frequency data for gravitational wave detection and denoising, demonstrating high accuracy and speed.

Findings

Successfully detected GW150914 signal in real data.

Reproduced all O2 binary black hole mergers.

Uncovered potential new 'ringing' pattern post-merger.

Abstract

We present a convolutional neural network, designed in the auto-encoder configuration that can detect and denoise astrophysical gravitational waves from merging black hole binaries, orders of magnitude faster than the conventional matched-filtering based detection that is currently employed at advanced LIGO (aLIGO). The Neural-Net architecture is such that it learns from the sparse representation of data in the time-frequency domain and constructs a non-linear mapping function that maps this representation into two separate masks for signal and noise, facilitating the separation of the two, from raw data. This approach is the first of its kind to apply machine learning based gravitational wave detection/denoising in the 2D representation of gravitational wave data. We applied our formalism to the first gravitational wave event detected, GW150914, successfully recovering the signal at all three phases of coalescence at both detectors. This method is further tested on the gravitational wave data from the second observing run ($O2$) of aLIGO, reproducing all binary black hole mergers detected in $O2$ at both the aLIGO detectors. The Neural-Net seems to have uncovered a pattern of 'ringing' after the ringdown phase of the coalescence, which is not a feature that is present in the conventional binary merger templates. This method can also interpolate and extrapolate between modeled templates and explore gravitational waves that are unmodeled and hence not present in the template bank of signals used in the matched-filtering detection pipelines. Faster and efficient detection schemes, such as this method, will be instrumental as ground based detectors reach their design sensitivity, likely to result in several hundreds of potential detections in a few months of observing runs.