An atlas of synthetic line profiles of planetary nebulae

TL;DR

This paper presents a comprehensive grid of synthetic line profiles for planetary nebulae, aiding interpretation of observations and revealing degeneracies in nebular geometry and velocity field recovery.

Contribution

It introduces a detailed atlas of model line profiles for various nebula geometries and velocity fields, enhancing understanding and analysis of planetary nebulae data.

Findings

Line profiles are often degenerate, complicating geometry and velocity field interpretation.

Mass-weighted expansion velocities can be accurately estimated from line widths using HWHM.

For distant nebulae, unknown geometry and orientation have minimal impact on measured velocities.

Abstract

We have constructed a grid of photoionization models of spherical, elliptical and bipolar planetary nebulae. Assuming different velocity fields, we have computed line profiles corresponding to different orientations, slit sizes and positions. The atlas is meant both for didactic purposes and for the interpretation of data on real nebulae. As an application, we have shown that line profiles are often degenerate, and that recovering the geometry and velocity field from observations requires lines from ions with different masses and different ionization potentials. We have also shown that the empirical way to measure mass-weighted expansion velocities from observed line widths is reasonably accurate if considering the HWHM. For distant nebulae, entirely covered by the slit, the unknown geometry and orientation do not alter the measured velocities statistically. The atlas is freely accessible from internet. The Cloudy_3D suite and the associated VISNEB tool are available on request.