The following document lists the file abstract/RSTARK_CIRRUS.abs
from catalogue VI/111.
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===================================================================== ==> In this proposal, more time is being requested for RSTARK.COOLLINE ===================================================================== We propose to take deep LWS02 observations of the [CII] 157.7 mu line, as well as medium resolution wavelength range LWS01 scans necessary to analyze existing data of the [OI] 63.2 mu line in a sample of well studied high-latitude cirrus clouds. Most of these clouds have already been observed using LWS02. However, the need to defringe the medium resolution line spectrum observations requires rather longer wavelength observations than originally anticipated. The fringing has strongest impact at 63.2 microns. Without defringing, the [OI] spectra cannot be interpreted. At 158 microns the fringing pattern has a longer period and is less disturbing. The results so far show that [CII] emission in quiescent cirrus clouds is weak and ubiquitous. Higher S/N LWS02 [CII] spectra are necessary to investigate the variation in each cloud as well as among the clouds, and to separate the contribution from the diffuse ionized interstellar medium along the line of sight. The LWS observations will provide a direct tool to study the carbon chemistry: [CII]--> [CI] --> CO, and the cooling by [OI] and [CII]. The primary target of our sample is the HD 210121 (G056) cloud. This is one of the best characterized quiescent high-latitude clouds to date. The other high priority clouds G228-29 and G230-28 are cometary cirrus clouds which are connected by their tails. The latter two have very peculiar HI, CO, and FIR properties. Their 60/100 mu brightness ratio is one of the highest known among cirrus. They are thought to be shocked by the same collision, and to be at present in a different stage of shock completion. The cooling lines will provide unique information on the physical/chemical state and the differences between quiscent and shocked nearby simple clouds.