| Description |
Despite the increasing evidence that the anomalous emission
is a new physical mechanism acting in the diffuse interstellar
medium, the nature and distribution of this component remains
elusive. The currently most favored models attribute the observed
microwave excess to rotating very small dust grains (PAHs and VSGs).
Nonetheless, the infrared properties of the sources which, to date,
are known to exhibit this type of emission are very poorly known
mostly due to the limited angular resolution and frequency
coverage of DIRBE and IRAS data.
We propose HERSCHEL PACS and SPIRE mapping
of three Galactic anomalous emission sources (LDN 1780,
LDN 675 and LDN 1111). This data, when combined with ancillary
NIR and mid-IR data of comparable angular resolution (mainly from Spitzer),
and coupled with available dust models, will allow to set tight constraints
on the radiation field in the emitting sources as well as in their immediate
surroundings. Such constraints, in turn, will allow to estimate
the abundances of PAHs, VSGs and BGs, hence to shed light on the
potential link between these dust populations and the observed microwave excess. |
