Contents of: VI/111/./abstract/NEVANS_PHOTOION.abs

The following document lists the file abstract/NEVANS_PHOTOION.abs from catalogue VI/111.
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 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.

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