Post-Merger Jets from Supermassive Black Hole Coalescences as Electromagnetic Counterparts of Gravitational Wave Emission

TL;DR

This paper models the electromagnetic signals from jets emitted after supermassive black hole mergers, predicting detectable multi-wavelength emissions that can serve as electromagnetic counterparts to gravitational wave signals.

Contribution

It introduces a detailed model of post-merger jet propagation and EM spectra, providing predictions for observable signals as counterparts to GW events.

Findings

EM signals detectable up to LISA horizon

Predicted transients fade over days to months

Implications for EM follow-up after GW detection

Abstract

As a powerful source of gravitational waves (GW), a supermassive black hole (SMBH) merger may be accompanied by a relativistic jet that leads to detectable electromagnetic (EM) emission. We model the propagation of post-merger jets inside a pre-merger circumnuclear environment formed by disk winds, and calculate multi-wavelength EM spectra from the forward shock region. We show that the non-thermal EM signals from SMBH mergers are detectable up to the detection horizon of future GW facilities such as the Laser Interferometer Space Antenna (LISA). Calculations based on our model predict slowly fading transients with time delays from days to months after the coalescence, leading to implications for EM follow-up observations after the GW detection.