Search for Faint Lone Double-Peaked H$\alpha$ Lines as IMBH Signatures in the MUSE Deep Field

TL;DR

This study reanalyzed deep MUSE data to find faint double-peaked Hα lines as signs of wandering intermediate-mass black holes, using automated detection, but found no candidates, highlighting detection challenges and future potential.

Contribution

It introduces an automated detection method applied to deeper MUSE data for identifying IMBH signatures, contrasting with previous visual approaches.

Findings

No candidate IMBH signatures detected in MXDF data.

Automated detection approach shows promise for future searches.

Highlights challenges in detecting faint IMBH signatures.

Abstract

Double-peaked H$\alpha$ emission profiles can serve as potential signatures of accreting intermediate-mass black holes (IMBHs), particularly those residing outside galactic nuclei. Such features are expected to arise from rotating disk-like structures around black holes and can be used to identify elusive IMBH candidates. \citet{Almeida2022ApJ...934..100S} reported a sample of such double-peaked H$\alpha$ sources in the MUSE-Wide survey, interpreting them as potential signatures of wandering IMBHs after systematically excluding alternative explanations. Their method relied on constructing H$\alpha$ maps around central galaxies and visually identifying compact emission clumps in the surrounding halo regions. In this work, we revisit the analysis using the deeper MUSE Extremely Deep Field (MXDF) data and an automated detection algorithm tailored to identify such features. However, we do not recover any candidate population in MXDF, resulting in a null detection. This outcome is nevertheless informative, as it (1) highlights the inherent challenges in detecting IMBHs, and (2) demonstrates the potential of automated approaches for future systematic searches, even though it did not yield a positive outcome in this case.