we propose to obtain images of reflection nebulae with isocam and the circular variable filter (cvf), in order to determine the spatial distribution of specific infrared emission features (iefs) within each nebula. our sample includes reflection nebulae with tstar, the temperature of the illuminating star, ranging from 3,600 k to 33,000 k. we will obtain cvf images in iefs at 6.2, 7.6, 8.6, and 11.2 um; cvf images at 7.0, 8.3, and 12.0 um to study broad spectral features at 6-9 um and 11-13 um; cvf images at continuum wavelengths of 9.5 and 10.5 um; and broad-band continuum images at 4.5 um (lw1) and 15.0 um (lw9). our goals are to (1) compare the spatial distributions within a reflection nebula of different iefs, other broad spectral features, and the continuum in order to determine whether these features have a common origin; (2) determine the photon energies required to excite each spectral feature and the infrared continuum by obtaining isocam images with the cvf in reflection nebulae with widely varying tstar; (3) compare isocam images of infrared continuum emission to ground-based images of extended red emission; (4) compare the spatial distributions of iefs and molecular hydrogen emission within a reflection nebula. each of these observations, described in more detail below, will be compared to model predictions for polycyclic aromatic molecules, hydrogenated amorphous carbon grains, and other laboratory materials. isocam observations are needed because of its superb sensitivity to low surface brightness mid-infrared emission, which is far higher than the sensitivity achievable from ground-based or airborne telescopes whose background thermal emission peaks in the wavelength region of interest.
Instrument
CAM03
Temporal Coverage
1996-03-19T10:25:38Z/1998-02-16T11:01:50Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
