Relativistic Binary Precession: Impact on Eccentric Binary Accretion and Multi-Messenger Astronomy

TL;DR

This study investigates how general relativistic precession affects the accretion behavior and observable signals of eccentric binary black holes in circumbinary disks, with implications for multi-messenger astronomy.

Contribution

It provides the first detailed hydrodynamical simulations of GR apsidal precession effects on eccentric binary black holes in circumbinary disks.

Findings

GR precession modulates accretion rates and electromagnetic light-curves.

Precession signatures can help constrain binary parameters.

Potential observability in electromagnetic and gravitational wave signals.

Abstract

Recent hydrodynamical simulations have shown that circumbinary gas disks drive the orbits of binary black holes to become eccentric, even when general relativistic corrections to the orbit are significant. Here, we study the general relativistic (GR) apsidal precession of eccentric equal-mass binary black holes in circumbinary disks (CBDs) via two-dimensional hydrodynamical simulations. We perform a suite of simulations comparing precessing and non-precessing binaries across a range of eccentricities, semi-major axes, and precession rates. We find that the GR precession of the binary's semi-major axis can introduce a dominant modulation in the binary's accretion rate and the corresponding high-energy electromagnetic light-curves. We discuss the conditions under which this occurs and its detailed characteristics and mechanism. Finally, we discuss the potential to observe these precession signatures in electromagnetic and gravitational wave (GW) observations, as well as the precession signal's unique importance as a potential tool to constrain the mass, eccentricity, and semi-major axis of binary merger events.