Effects of vertical advection on multimessenger signatures of black hole neutrino-dominated accretion flows in compact binary coalescences

TL;DR

This paper investigates how vertical advection in neutrino-dominated accretion flows affects their structure, emissions, and associated multimessenger signals in binary coalescence events, providing insights for future observational discrimination.

Contribution

It introduces the effects of vertical advection on NDAF structure, luminosities, and multimessenger signatures, highlighting potential observational differences.

Findings

Vertical advection slightly decreases neutrino luminosity and GW strains.

Gamma-ray photons brighten kilonovae emissions.

Future observations could identify the presence of vertical advection in NDAFs.

Abstract

In the coalescence events of binary neutron star (NS) or a black hole (BH) and an NS, a BH hyperaccretion disk might be eventually formed. At very high mass accretion rates, MeV neutrinos will be emitted from this disk, which is called a neutrino-dominated accretion flow (NDAF). Neutrino annihilation in the space out of the disk is energetic enough to launch ultrarelativistic jets to power gamma-ray bursts. Moreover, vertical advection might exist in NDAFs, which can generate the magnetic buoyancy bubbles to release gamma-ray photons. In this paper, we visit the effects of the vertical advection in NDAFs on the disk structure and gamma-ray and neutrino luminosities for different accretion rates. Then we study the anisotropic emission of kilonovae and the following gravitational waves (GWs) driven by the gamma-ray photons and neutrinos from NDAFs. Comparing NDAFs without vertical advection, the neutrino luminosity and GW strains slightly decrease for the case with vertical advection, and the kilonovae will be brightened by the injected gamma-ray photons. The future joint multimessenger observations might distinguish whether the vertical advection exists in NDAFs or not after compact binary coalescences.