Spatial resolution bias in the mid-infrared Starburst/AGN classification
  We present the effects of limited spatial resolution to the observed mid-infrared (MIR) spectrum of an active galactic nucleus (AGN) surrounded by a disk with massive star forming regions. Using MIR observations of the face-on nearby Seyfert 1 galaxy NGC 6814, we vary the observing aperture and examine the evolution of the observed AGN/starburst fraction with our MIR diagnostic. We show that the spatial resolution of ISOCAM is sufficient to disentangle AGN from starburst features in nuclear regions of nearby galaxies (D<50Mpc). However, with the exception of a few ultra-luminous galaxies, dilution effects hide completely the AGN contribution in more distant galaxies. 
O. Laurent (1,2), I.F. Mirabel (1,3), V. Charmandaris (4,5), P.   Gallais (1), M. Sauvage (1), L. Vigroux (1) and C. Cesarsk...