We present observations of near-infrared H2 line emission toward the reflection/emission nebulae, IC 59 and IC 63, and the planetary nebula, NGC 1535. Each source has been observed previously in the ultraviolet, where H2 was detected in emission toward IC 63 and in absorption toward NGC 1535. In IC 63, we have detected the 1.601 μm ν = 6-4 Q(1), 2.121 μm ν = 1-0 S(1), and 2.247 μm ν = 2-1 S(1) lines of H2 arising from a near-infrared fluorescent cascade following ultraviolet continuum pumping. The detection marks the first time that both infrared and ultraviolet portions of the H2 fluorescent cascade have been measured in a region exposed to far-ultraviolet continuum photons. Furthermore, we also report 1-0 S(1) and 2-1 S(1) fluorescent emission toward IC 59, a source previously thought to display no H2 fluorescence and considered devoid of molecules based on ultraviolet and CO observations. Toward NGC 1535, we find no H2 emission in the near-infrared, in spite of the reported ultraviolet H2 absorption.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science