The Search for Binary Black holes in Seyferts with Double Peaked Emission Lines

TL;DR

This study used VLBI observations to search for binary black holes in Seyfert galaxies with double peaked emission lines, but found nuclear outflows instead of binary cores, suggesting outflows may cause the spectral features.

Contribution

The paper provides the first VLBI observational results targeting binary black hole candidates in Seyferts with double peaked lines, highlighting outflows as an alternative explanation.

Findings

No twin radio cores detected, indicating no binary black holes.

Detected nuclear outflows interacting with emission line clouds.

Outflows may produce double peaked emission lines instead of binary black holes.

Abstract

We discuss results from very long baseline interferometry (VLBI) observations of two Seyfert galaxies with double peaked emission lines in their SDSS optical spectra. Such AGN are potential candidates for the presence of binary black holes, which can be resolved on parsec-scales with VLBI. Our observations do not detect twin radio cores but rather nuclear outflows in these Seyferts. These outflows could be interacting with the emission line clouds producing the double peaks in the emission lines.