Gravitational-wave localization alone can probe origin of stellar-mass black hole mergers

I Bartos,N C Stone,Z Haiman,Z Marka,B D Metzger,S Marka

doi:10.1038/s41467-017-00851-7

I Bartos, N C Stone + Show 4 more

Open Access

https://doi.org/10.1038/s41467-017-00851-7

Copy DOI

Abstract

The recent discovery of gravitational waves from stellar-mass binary black hole mergers by the Laser Interferometer Gravitational-wave Observatory opened the door to alternative probes of stellar and galactic evolution, cosmology and fundamental physics. Probing the origin of binary black hole mergers will be difficult due to the expected lack of electromagnetic emission and limited localization accuracy. Associations with rare host galaxy types—such as active galactic nuclei—can nevertheless be identified statistically through spatial correlation. Here we establish the feasibility of statistically proving the connection between binary black hole mergers and active galactic nuclei as hosts, even if only a sub-population of mergers originate from active galactic nuclei. Our results are the demonstration that the limited localization of gravitational waves, previously written off as not useful to distinguish progenitor channels, can in fact contribute key information, broadening the range of astrophysical questions probed by binary black hole observations.

Highlights

The recent discovery of gravitational waves from stellar-mass binary black hole mergers by the Laser Interferometer Gravitational-wave Observatory opened the door to alternative probes of stellar and galactic evolution, cosmology and fundamental physics
We find that ~70 detections would be sufficient to statistically prove the binary black hole (BBH)-active galactic nuclei (AGN) connection if all BBH mergers occurred in AGN
Even if only a fraction of mergers occur in AGN, we find that a 5-year observation period is likely sufficient to statistically prove the BBH-AGN connection if the AGN fraction is at least 25%

Summary

Introduction

The recent discovery of gravitational waves from stellar-mass binary black hole mergers by the Laser Interferometer Gravitational-wave Observatory opened the door to alternative probes of stellar and galactic evolution, cosmology and fundamental physics. Probing the origin of binary black hole mergers will be difficult due to the expected lack of electromagnetic emission and limited localization accuracy. Identifying the BBH formation channel will be a key step in using BBH mergers as cosmic probes This identification for a single merger is difficult without an electromagnetic counterpart[5], which can only be produced if the binary is surrounded by sufficient gas that can be accreted. This is not expected for most formation channels The situation is complicated further if multiple formation channels are present, requiring the statistical study of rare events

Objectives

Methods

Results

Conclusion