The analysis of very small carbonaceous dust particles emission as a probe
of astrophysical environments.
Olivier BERNE
Centro de Astrobiologia (CSIC/INTA), Madrid
Résumé :
The so called "Aromatic Infrared Bands" (AIBs), seen in spectroscopy
throughout the mid-infrared universe, are generally attributed to
the emission of carbonaceous macromolecules heated by the UV photons
of massive stars. During its years of cryogenic activity, the Spitzer
Space Telescope has provided a wealth of mid-IR spectroscopic data,
from all types of environments showing AIB emission.
In this seminar, I will first present the signal processing analysis
we have conducted at CESR in Toulouse on Spitzer spectral cubes
of Photodissociation regions. This analysis enabled us to identify
the "pure" spectra of different families of carbonaceous
macromolecules/grains, each population beeing related to particular UV field
strengths (Berne et al 2007). I will then show how the results
of this first analysis was extended to build a mid-IR emission model.
This model was used to probe the physical conditions of planetary nebulae
(Joblin et al. 2008), protoplanetary disks (Berne et al. 2009),
ultracompact HII regions (Berne et al. 2009), and galaxies.
More generally, I will discuss how the shape of AIBs, seen in
many environments even at high redshifts, can be used as a probe
of local UV field conditions and possibly star formation activity.
