English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Within the project Galactic Cold Cores we are carrying out Herschelphotometric observations of cold interstellar clouds detected with the Plancksatellite. The three fields observed as part of the Herschel sciencedemonstration phase (SDP) provided the first glimpse into the nature of thesesources. We examine the properties of the dust emission within the fields. Wedetermine the dust sub-millimetre opacity, look for signs of spatial variationsin the dust spectral index, and estimate how the apparent variations of theparameters could be affected by different sources of uncertainty. We use theHerschel observations where the zero point of the surface brightness scale isset with the help of the Planck satellite data. We derive the colourtemperature and column density maps of the regions and determine the dustopacity by a comparison with extinction measurements. By simultaneously fittingthe colour temperature and the dust spectral index values we look for spatialvariations in the apparent dust properties. With a simple radiative transfermodel we estimate to what extent these can be explained by line-of-sighttemperature variations, without changes in the dust grain properties. Theanalysis of the dust emission reveals cold and dense clouds that coincide withthe Planck sources and confirm those detections. The derived dust opacityvaries in the range kappa(250um) ~ 0.05-0.2 cm^2/g, higher values beingobserved preferentially in regions of high column density. The average dustspectral index beta is ~ 1.9-2.2. There are indications that beta increasestowards the coldest regions. The spectral index decreases strongly nearinternal heating sources but, according to radiative transfer models, this canbe explained by the line-of-sight temperature variations without a change inthe dust properties.

Galactic cold cores II. Herschel study of the extended dust emission around the first Planck detections