The following document lists the file abstract/PMEZGER_PGMSTAR2.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
SCIENTIFIC ABSTRACT
The prime scientific goal is to obtain precise, well spectrally sampled
absolute photometry in the 2.5 - 200 microns wavelength range of a
complete sample of a compact dense condensations of cold dust and gas,
selected by sensitive, high angular resolution surveys of cloud cores at
mm/sub mm wavelengths. The high precision FIR/MIR spectra, supplemented by
MIR/NIR diffraction limited imaging, will differentiate between various
evolutionary stages, allowing true isothermal protostars, disk and cocoon
stars to be distinguished from one another. The relative detection rate of
these phenomena will reflect the true incidence of these objects within
each of the cloud cores surveyed in the submm, and will therby allow
statements to be made about the duration of the evolutionary stages of star
formation.
OBSERVATION SUMMARY
For investigation of nearby protostar candidates and their parent clouds:
P25 rasters of subfields (3x3 up to 7x7 depending on cloud size)
at 200, 100, 60 micron with Tint = 5s. Raster step interval = array
repeat length (180, 138 arcsec for C200, C100). To be performed concatenated.
For each individual protostar candidate within cloud, perform concatenated:
P05 1x11,1x10 rasters at 25 micron, using 10 arcsec aperture and minimal
raster step of 10 arcsec. The sum of these will provide 5" sampling over a
100" scanlength. To provide information about the background outside the
cloud an additional P05 1x7 raster with 50" raster step is proposed. All
P05 rasters use Tint=5s.
P32 at 200, 160, 120 micron (4x2)raster, O/S 2, Tint = 10s per S/C raster
point.
P32 at 100, 70, 60 micron (4x2)raster, O/S 2/3, Tint = 10s per S/C raster
point.
P40 in a 5x1 raster Tint = 32s. (Raster interval chosen to provide 1 point
on protostar candidate, 2 points on parent cloud, 2 points on background)
For investigation of distant star forming clouds we propose the following:
P25 rasters of subfields (3x3) 200, 100, 60 micron with Tint = 5s.
Raster step interval = array repeat length (180, 138 arcsec for C200, C100).
Centered at the cloud core, perform concatenated:
P05 1x5 raster at 25 micron, using Tint=5s and 23 arcsec aperture
(Raster interval chosen to provide 1 point on cloud core, 2 points on cloud,
2 points on background)
P40 in an identical 5x1 raster Tint = 32s.
P32 at 200, 160, 120 micron (4x2)raster, O/S 2, Tint = 10s per S/C raster
point.
P32 at 100, 60 micron (4x2)raster, O/S 2/3, Tint = 10s per S/C raster point.
VISIBILITY CONSIDERATIONS: Although the source list has been taylored to avoid
the holes in sky visibility, some sources of exceptional scientific interest
have been retained despite positions of marginal or zero visibility for the
standard launch in the 5 degree visibility binning scheme. Specifically, SM1
and RHO OPH B2 may be problematic for the spring launch and the Orion protostar
candidates for the autumn launch. Whether or not these sources will be visible
will depend critically on the time of night of launch. Therefore, we propose
that these sources be retained in the source lists for the present.