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==> In this proposal, more time is being requested for ALEGER.RN
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The aim of this proposal is to get HIGH QUALITY SPECTRA of the two
brightest reflection nebulae, NGC7023 and NGC2023, in restricted
wavelength ranges, to SEARCH FOR WELL-DEFINED FEATURES OF AROMATIC
COMPOUNDS:
(1) around 7 mic. we expect the IR signature of the cation C60+
which has been detected in another spectral domain.
(2) 13 - 25 mic. is a wavelength range where PAH features
are measured in the lab but have never been searched for in the
interstellar medium,
because there is no ground-based access to these wavelengths and the
sensitivity of previous spectrometers on the KAO and on IRAS was
not good enough.
ISO with the SW spectrometer can cover these ranges with
sufficient sensitivity on the brightest objects.  Our proposed
spectra will address size distribution of PAHs, and the nature of aromatic
species in the interstellar medium (ISM).