The following document lists the file abstract/RLISEAU_OPH_CORE.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
======================================================================= ==> In this proposal, more time is being requested for RLISEAU.RHOPSPEC ======================================================================= In the star forming rho Ophiuchi cloud (L 1688), maximum emission occurs in the spectral regime of the LWS, whose spatial resolution is typically of the order of the Jeans length. We wish to investigate the relative importance of H2O cooling in locations exhibiting a considerable range in physical conditions (from cold dense to hot diffuse) and wish to explore to what extent and on what spatial scales warm gas co-exists with cold dust and, on the other hand, where, to what extent and under what circumstances the gas and dust are well coupled. The LWS is capable of detecting any cold dust, unseen by IRAS and associated with the cold gas in what was discovered by ISO as `absorption cores'. Further, the LWS offers the opportunity to observe a number of rotational transitions of H2O, OH and CO, which are collisionally excited already by quite weak shocks (shock velocities of order 10 km/s), whereas fast shocks produce also easily detectable emission from neutral atomic oxygen at 63 mu and 145 mu. The degree of penetration of UV radiation into the cloud will be mapped by the distribution of the 158 mu line of singly ionized carbon (photodissociation product of the cloud's PDRs) at significantly higher spatial resolution than what has previously been accomplished. We propose full grating scan spectra be obtained, largely unbiased, in a one-dimensional raster scan mode (strip scan) along a line which includes regions of both relatively bright emission and of dark, presumably prestellar, cores, seen in absorption at mid-infrared wavelengths. The grating provides suitable resolution for the observational study of both the gas and the dust. Observing time has been allocated to this programme (RLISEAU_RHOPSPEC) for two strip scans (one grade 2 and one grade 3) and we ask for upgrading. Most importantly, though, we ask for the acceptance of the (previously dropped) scan through the dark cloud cores D, B and C, which in recent ISOCAM observations appear in absorption and the information of which cannot be retrieved from the other scans, not passing through absorption cores.