The following document lists the file abstract/JFISCHER_IRB_HD.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
Several of the full LWS spectra of IR bright galaxies observed to date are dominated by clear absorption and possible faint emission in a number of molecular species including OH, HD, and CH (or HeH+). These spectra are indicative of very high column densities/extinction, as is also found by the SWS Instrument team (eg. Lutz et al. 1996, A&A ISO Issue). This proposal is one of several follow-up proposals designed to verify and study the cloud conditions, chemistry, and column densities in a sample of bright galaxies. > Here we request time for deep LWS grating observations of the HD 112 um (J = 1-0), HD 56 um (J = 2-1) (for two galaxies), and CH 149 um lines in a small sample of bright galaxies in which we believe they are bright enough to be detected at the level seen in M82 and for which LWS and SWS spectra have been obtained. Estimation of the molecular column densities toward these heavily obscurred galactic nuclei can be used to infer the column density of H_2 with minimum dependence on the gas metallicity, using the current estimates of the abundance of D/H.