we propose to obtain the first complete, fully-sampled map of a nearby prototypical giant molecular cloud (gmc) - either w3 (spring launch) or ngc 7538 (fall launch) - at wavelengths of 135 and 200 microns, corresponding to the expected peak in the spectral energy distributions (seds) of these objects. these data will be combined with our existing optical and infrared images, iras issa and hires images, proposed submillimeter (350 - 1300 micron) maps, and radio continuum maps to provide the first complete picture of the sed within a gmc on spatial scales of virgul1 arcmin (virgul0.6 pc). existing data indicate that most of the molecular gas in gmcs (>80%) is not directly associated with the more widely studied, warm, massive ob star-forming cores. over most of the projected area of a gmc, both the ambient material and the lower mass star-forming cores appear to emit the bulk of their luminosity in the 100 - 250 micron band. thus our iso data will allow us, for the first time, to carry out a complete census of the true distribution of luminosity sources throughout a gmc, and to make greatly improved estimates of the dust temperature and heating and cooling rates, which can then be used to construct more realistic models for the origin and evolution of gmcs.
Instrument
PHT37 , PHT38 , PHT39
Temporal Coverage
1997-01-12T12:34:31Z/1997-01-25T18:26:03Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds 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.
European Space Agency, SANDERS et al., 1999, 'The 135 - 200 micron luminosity of nearby comma star-forming GMCs: W3 and NGC 7538 openParPart 3 of 4closePar ', 1.0, European Space Agency, https://doi.org/10.5270/esa-liu8g16
