we propose to carry out observations of some intermediate redshift clusters ( z=0.4) with cam and phot. selected clusters have been extensively studied by authors of this proposal. membership has been derived for all their galaxies. further, we derived morphology and spectral energy distribution (sed) from u (or b) band up to i (or k) band for all cluster galaxies. the role of the dust inside blue, starburst galaxies and e+a galaxies, both being a large fraction of our cluster.s population, is by far completely unknown. the overabundance of blue galaxies in clusters is expected since 1978 (butcher-oemler effect), however it is well known by now a bluening of the field galaxy population at the same redshift. planned observations will allow us to investigate for the first time over a very large spectral range: _the evolutionary properties of each single galaxy inside the clusters, _the average evolutionary properties for morphological type, as well as _the effects of mergers, interactions and starbursts shedding light, in a self-consistent way, both on the evolutionary properties of the ir luminosity, a good tracer of the star formation rate, and on the related optical-near-ir sed of these cluster galaxies. by comparing these results with those of field galaxies at the same redshift, we could derive statistical information on the frequency and on the intensity of these phenomena in different environments. e+a galaxies are a peculiar class of elliptical cluster galaxies showing redder colours than those of field ellipticals. following recent suggestions they are post-starburst galaxies. ir data can dissipate our doubts on their nature since the ir sed is strongly dependent both on the intensity and on the age of the burst. evolutionary properties of normal and starburst galaxies in intermediate clusters will be investigate.
Instrument
CAM01 , PHT37 , PHT38 , PHT39
Temporal Coverage
1996-12-14T19:21:01Z/1996-12-17T18:15:12Z
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, BONOLI et al., 1998, 'INFRARED PROPERTIES OF GALAXIES IN INTERMEDIATE REDSHIFT CLUSTERS', 1.0, European Space Agency, https://doi.org/10.5270/esa-4dj8z12
