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We propose to observe a sample of Narrow Line Seyfert 1 galaxies (or quasars)
(NLS1) with CAM, PHT-C and for the brightest galaxies, PHT-S and PHT-P. NLS1
are a peculiar sub-class of Active Galactic Nuclei (AGN) characterized by
narrow permitted lines and a strong and steep soft X-ray excess. About 45 such
objects have been identified to date, 33 of which are still observable with
ISO. Two schemes have been proposed to explain the correlation between line
width and steepness of the soft X-ray slope: either (1) NLS1 are normal S1 seen
close to pole-on with the further assumption that the accretion disk is
geometrically thick or (2) NLS1 represent a short lived episode of high
accretion rate in otherwise low mass AGN. Different Spectral Energy
Distribution (SED) are predicted by the two models. The aim of our proposal
is to map the NLS1 (SED) and compare it with that of normal Seyfert 1 so
as to test the validity of the models. This proposal is an extension of our
GT programme SEYFERT/JCLAVEL to observe the 2-12 micron spectrum of normal
AGN in the CfA sample with PHT-S and CAM.