# Searching for intermediate-mass black holes in NGC3310

## TL;DR

This study investigates potential intermediate-mass black holes in NGC3310 by combining X-ray and radio observations, detecting a compact radio source near an X-ray source indicative of a black hole with an estimated mass of about 30,000 solar masses.

## Contribution

The paper presents new high-resolution radio observations that identify a candidate intermediate-mass black hole in NGC3310, providing direct evidence supporting their existence.

## Key findings

- Detection of a compact radio source near an X-ray source.
- Estimated black hole mass of approximately 3×10^4 solar masses.
- Evidence of jet activity associated with the candidate black hole.

## Abstract

Intermediate-mass black holes are theoretically predicted but observationally elusive, and evidence for them is often indirect. The nearby face-on spiral galaxy NGC3310 has hosted many supernovae in recent history, and recent Chandra observations have shown a group of strong off-nuclear X-ray sources that are coincident with radio emission seen in archival VLA and MERLIN observations. Their luminosity, spectrum and off-nuclear location make these sources excellent IMBH candidates. To investigate this possibility, we used combined EVN/e-MERLIN observations at both 1.4 and 5 GHz to look for compact radio emission and evidence of jet activity. We detect a compact radio source within one arcsecond of a Chandra source with an estimated mass ${\rm M}_{\rm BH}\sim3\times10^4 {\rm M}_{\odot}$.