| Description |
Despite of all theoretical speculations and various observational
constraints, the nature of the dark matter in the outer Galaxy is
still unknown. Herschel/HIFI offers the unique opportunity to detect
or set a significant upper limit to a potential component of baryonic
matter in the form of cold gas, which is molecular in hydrogen, but
does not form CO. Such gas can be potentially be traced through [CII]
150 um and HF J=1-0 absorption against continuum background
sources. We propose a set of 7 the brightest outer Galaxy dust
continuum sources, for which we will determine the positions of peak
emission by PACS mapping. Deep integrations in [CII] and HF towards
the 4 brightest peaks in these sources will potentially detect a cold
gas component and will, in any case, give significant upper limits to
its column density. |
