Near-IR Fluorescent Molecular Hydrogen Emission from NGC 2023

Abstract

Spectra from 1 to 2.5 micrometres, at 230-430 spectral resolution, are presented of the fluorescent molecular hydrogen line emission from two locations in the reflection nebula NGC 2023. Over 100 H2 lines can be identified in the spectra, although blending and poor atmospheric transmission mean that reliable level column densities can only be obtained from 35 lines. This latter group includes lines from v = 1-8 and v = 10, spanning an energy range from 6000 to 45,000 K above the ground state These data may be used to constrain models of photodissociation regions and of fluorescent excitation for molecular hydrogen.