Unveiling supermassive black hole binaries with FUV-to-NIR spectropolarimetry

TL;DR

This paper discusses how FUV-to-NIR spectropolarimetry, using instruments like POLLUX, can improve detection and characterization of supermassive black hole binaries, complementing traditional methods and advancing extragalactic research.

Contribution

It proposes using high-resolution FUV-NIR spectropolarimetry as a novel approach to identify and study supermassive black hole binaries, enhancing current detection techniques.

Findings

Spectropolarimetry can confirm or refute binary black hole candidates.

A POLLUX-like instrument would be ideal for this purpose.

This method could significantly advance extragalactic black hole research.

Abstract

In this proceedings, we review the importance and complexity of detecting and characterizing supermassive binary black holes using conventional techniques (spectroscopy, timing, imaging). We show how spectropolarimetric data can strengthen or discard binary black hole candidates on solid grounds, and present what kind of instrument could perform this task. Namely, a high spectral resolution polarimeter operating from the far-ultraviolet (FUV) to the near-infrared (NIR), such as the POLLUX prototype, would perfectly fit within the payload of the Habitable Worlds Observatory and help revolutionize the study of extragalactic objects.