The following document lists the file abstract/AHEITHAU_AHE_HVC.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
HI high-velocity clouds (HVCs) have so far only be seen in the 21cm line of atomic hydrogen and as absorption features in optical spectra towards distant quasars. No firm estimates on their distances exist. Therefore almost nothing is known about their chemical composition and physical parameters. Despite several attempts no CO has been found in HVCs. Therefore the dominant cooling line for the clouds should be the 157.7micron [CII] fine structure line which we want to study towards an HI high-velocity cloud which is likely to interact with an intermediate velocity cloud. Both clouds are positionally anticorrelated on the sky with almost no overlap between them. This unique positioning on the sky makes it possible to observe the [CII] line of the HVC without applying the time consuming Fabry-Perot mode of the LWS which provides high frequency resolution. To get information on the interstellar radiation field of both clouds we want to observe two positions, one towards the IVC and one towards the HVC. The comparison of both positions will then give hints on the composition of the HVC and thus on its possible origin.