we propose to map the distribution of the c+ line emission across the southwest portion of the smc, in order to study the physical conditions of interstellar gas with a much lower metallicity than that of typical clouds in the milky way. our observations are coordinated with the ongoing ground-based observations of the molecular gas distribution with the sest, and will have resolution comparable to recently completed hi gas maps made with the atca. comparison of previous, low-resolution co and c+ observations of the lmc already indicated that the magellanic clouds present quite different emission lines, with the c+ enhanced relative to co by a factor of 18 in comparison with milky way clouds. with similarly bright lines expected from the smc, which has even more extreme metallicity than the lmc, it is possible to map a significant region at 80 resolution using the iso lws. the region selected contains prominent peaks in the co distribution, presumably giant molecular clouds, with some hii regions and supernova remnants around the edges of the selected region. the proposed observations are significantly different from those already planned, which are complete grating spectra at a small number of positions, because we will be able to measure the sizes of the emitting regions for comparison with the recent co and hi observations. the emission from the milky way will be separated from that of the smc in two ways: by making differential measurements over the mapped regions, and by explicitly separating the milky way line for select positions using the high spectral resolution fabry-perot.
Instrument
LWS01 , LWS02 , LWS04
Temporal Coverage
1997-04-18T06:11:37Z/1997-05-11T12:42:34Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
