The scientific motivation for this proposal is to trace the evolution of dust grains in relation to changes of the physical, dynamical and chemical properties of the interstellar medium. This program will provide an unprecedented view of the structure of the ISM at far-infrared and submillimeter wavelengths and will enable us to investigate the impact of dust grains on the ISM physical and chemical state.
The program will take full advantage of four unique characteristics of SPIRE and PACS: brightness sensitivity, wavelength coverage, angular resolution, and mapping efficiency. The brightness sensitivity is essential to measure the faint infrared emission from the diffuse regions. The spectrometers will provide the necessary information to derive the physical properties of the atomic and molecular gas and completely characterize dust evolution. The angular resolution is critical for tracing the dominant processes in grain evolution which takes place on all scales down to a few arcseconds. The data statistics will allow us to probe the impact of extreme physical conditions, e.g., high densities, intense vortices or illumination, on the dust evolution.
Our goal is to build with Herschel a coherent database on interstellar dust emission extending to much smaller angular scales than the IRAS and DIRBE surveys and covering a wide range of ISM physical conditions, from diffuse clouds to the sites of star formation and protostars. The program is supported by state-of-art modelling of the dust emission and physical processes acting on dust as well as by on-going laboratory measurements of the grains properties at far-infrared and submillimeter wavelengths. The Herschel observations will benefit from ground-based ancillary data (HI and CO) and from Spitzer programs yielding a full description of the spectral energy... distribution of interstellar dust from the near-infrared to the submillimeter.
Publication
Far-infrared/submillimetre properties of pre-stellar cores L1521E, L1521F and L1689B as revealed by the Herschel SPIRE instrument - I. Central positions . Makiwa G. et al. . Monthly Notices of the Royal Astronomical Society, Volume 458, Issue 2, p.2150-2160 . 458 . 10.1093\/mnras\/stw428 . 2016MNRAS.458.2150M ,
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
