we will obtain far-infrared spectrophotometry of regions on the peripheries of star-forming clouds to determine atomic and dust continuum properties in regions without obvious star formation. in particular, we have chosen outlying regions of the l1630, s140, and ic5146 molecular clouds, based on our ground based studies, which have modest extinction (av = 5 - 15) and density (n = 1000 per cubic cm). regions like these include most of the mass in the interstellar medium, but their properties and role in star formation are poorly known. we are testing these regions for evidence of a distributed mode of star formation. examination of the iras data for these regions allowed us to define 1-d positional cuts (see figures in the paper version) which have a range in intensity of the interstellar radiation field (go = 10 - 170). we plan to observe the [cii] line at 158 microns and the [oi] lines at 63 and 146 microns across these cuts, using the lws. these lines, together with the continuum spectrum, will allow us to test pdr models in regimes where they have not previously been tested and, together with our ground-based studies, to pin down the physical and chemical conditions in these regions. knowledge of these conditions will allow us to test tracers of hydrogen column density, chemistry in cloud edges, and mckee.s theory that star formation is regulated by photoionization.
Instrument
LWS02 , SWS02
Temporal Coverage
1996-04-24T04:09:08Z/1998-02-09T10:59:44Z
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.
European Space Agency, 1999, Photoionization Regulated Star Formation Comma Cloud Structure Comma And Tracers Of The Neutral Ism, 1.0, European Space Agency, https://doi.org/10.5270/esa-qa97hpo
