scientific abstract: we propose a coherent program to study hii regions in selected normal (non-interacting, non-starburst, non-agn) galaxies in the near- to far-ir in coordination with the isophot, the lws and the sot consortia. the present part of the proposal consists in imaging all the targets in two filters: lw 2 (5.0-8.5 micrometers) and lw 3 (12-18 micrometers). emission in lw 2 will be dominated by ir emission bands and emission in lw 3 by hot dust. the nature and physics of both components are not well understood, and the iras 12 micrometer filter did not allow a clear separation between them. however iras and other observations have shown that the intensity of the ir bands and to some extent of hot dust (with respect to colder dust) are affected by the uv radiation field and by metallicity, and also that the ir band carrier(s) (pahs or related large molecules) are easily frozen on bigger grains or liberated from them. the planned observations will allow a much better understanding of these phenomena. together with the other coordinated iso observations and complementary ground-based observations they will yield a more complete picture of the physics of dust and possibly a full understanding of the thermal balance of dust and gas in galaxies. the chosen targets span a large range of properties and of distances, starting from the magellanic clouds where very detailed studies will be possible and including more distant galaxies. observation summary the observations combine the beam switching mode between the central region and a reference point, far away from the galaxy, and a raster map with some overlap between successive images. filters lw2 and lw3 are used in every case. the integration time is 2 sec. the expected sensitivity is a s/n ratio = 3 at the limit of the iras maps of extended galaxies.
Instrument
CAM01 , CAM03 , CAM04
Temporal Coverage
1996-02-05T15:43:00Z/1998-03-05T21:54:41Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds 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.
European Space Agency, Vigroux et al., 1999, 'Broad band Imaging of an extragalactic HII region sample .', 1.0, European Space Agency, https://doi.org/10.5270/esa-zh0vh2l
