Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275

TL;DR

This study detects far ultraviolet emission from a filament in NGC 1275 that aligns with hydrogen two-photon continuum predictions, supporting the particle heating model without requiring additional sources.

Contribution

It provides observational evidence for hydrogen two-photon emission in the Horseshoe filament, validating the particle heating model of Ferland et al. (2009).

Findings

Far ultraviolet flux matches hydrogen two-photon emission predictions.

No evidence needed for hot stars or CIV emission lines.

Supports the particle heating model for filament emission.

Abstract

Far ultraviolet emission has been detected from a knot of Halpha emission in the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected relative to the brightness of the Halpha line in the same spatial region is very close to that expected from Hydrogen two-photon continuum emission in the particle heating model of Ferland et al. (2009) if reddening internal to the filaments is taken into account. We find no need to invoke other sources of far ultraviolet emission such as hot stars or emission lines from CIV in intermediate temperature gas to explain these data.