A supermassive binary black hole with triple disks

TL;DR

This study uses high-resolution simulations to explore the formation, evolution, and observational signatures of supermassive binary black holes with triple disks, highlighting periodic UV light variations as potential detection signals.

Contribution

It provides detailed simulation insights into the accretion disk dynamics and predicts specific UV variability signatures for identifying supermassive BBHs.

Findings

Periodic UV light variations linked to orbital phase

Formation of individual accretion disks around each black hole

Potential observational method for detecting supermassive BBHs

Abstract

Hierarchical structure formation inevitably leads to the formation of supermassive binary black holes (BBHs) with a sub-parsec separation in galactic nuclei. However, to date there has been no unambiguous detection of such systems. In an effort to search for potential observational signatures of supermassive BBHs, we performed high-resolution smoothed particle hydrodynamics (SPH) simulations of two black holes in a binary of moderate eccentricity surrounded by a circumbinary disk. Building on our previous work, which has shown that gas can periodically transfer from the circumbinary disk to the black holes when the binary is on an eccentric orbit, the current set of simulations focuses on the formation of the individual accretion disks, their evolution and mutual interaction, and the predicted radiative signature. The variation in mass transfer with orbital phase from the circumbinary disk induces periodic variations in the light curve of the two accretion disks at ultraviolet wavelengths, but not in the optical or near-infrared. Searches for this signal offer a promising method to detect supermassive BBHs.