Molecular hydrogen fluorescence in the Eridanus superbubble

Abstract

The first far-ultraviolet (1350 - 1750 angstrom) spectral imaging observations of the Eridanus superbubble, obtained with the SPEAR/FIMS mission, have revealed distinct fluorescent emission from molecular hydrogen. Here we compare the observed emission features with those from a photodissociation region model with assumed illuminating stellar fields. The result shows rather high line ratios I-1580 / I-1610, which may imply the existence of high-temperature molecular clouds in the region. The H-2 fluorescence intensity shows a proportional correlation with H alpha emission, indicating that the fluorescence and the recombination emission have similar physical origins.