The ISOPHOT field galaxy sample Part 6

scientific abstract that the central regions of many galaxies are powerful infrared energy sources h as been, without a doubt, one of the major scientific discoveries of the past two decade s. however, we still understand very little of the phenomenology of infrared activ ity in galaxies: the frequency of its occurrence, its luminosity function, its relatio n to other galaxy properties such as hubble type, galaxy environment, the presence o f bars, or an active galactic nucleus. even less therefore, do we understand the under lying astrophysics of infrared activity in galaxies: the physical mechanisms by which such activity is triggeredboth interactions and barinstabilities seem implicated. indeed, it is hotly debated whether the underlying energy source is accretion onto a co mpact object or thermonuclear reactions in massive young stars produced in a burst of star formation. we propose to use isophot and isocam to study the phenomenology of infrared act ivity in a sample of 120 spiral galaxies. the selection was made by taking those galaxies in the rsa catalogue which are classified as spiral or lenticular with b_t<12. then, for each launch season, the 120 with the largest iso visibility were selected. galaxies designated as being in the virgo cluster in binggeli etal (astron. j., 1985, 90,1681) were excluded. about 50 % of these are barred or mixed morphological types. about 10 % are interacting or disturbed. this sample will provide statistical information on a variety of scientific questions related to starburst activity in galaxies. moreover, it will be the fundamental control sample against which to compare the properties of more pathological examples of infrar ed activity in galaxies. it will be a unique database on the infrared properties of galaxies for the astronomical community for many years. to obtain information about the spatial and spectral distribution of tru [truncated!, Please see actual data for full text]