The relation between column densities of interstellar OH and CH molecules

TL;DR

This study establishes a new close relationship between the column densities of interstellar OH and CH molecules based on observations of 16 sightlines, confirming theoretical oscillator strengths and model consistency.

Contribution

It introduces a new empirical relation between OH and CH column densities and confirms theoretical oscillator strengths for key transitions.

Findings

Established a new relation between OH and CH column densities.

Confirmed theoretical oscillator strengths for specific transitions.

Observed no difference between observed and modeled OH abundances.

Abstract

We present a new, close relation between column densities of OH and CH molecules based on 16 translucent sightlines (six of them new) and confirm the theoretical oscillator strengths of the OH A--X transitions at 3078 and 3082 \AA (0.00105, 0.000648) and CH B--X transitions at 3886 and 3890 \AA, (0.00320, 0.00210), respectively. We also report no difference between observed and previously modelled abundances of the OH molecule.