Heating of the interstellar medium in spirals: Mapping of nearby galaxies Part 1

scientific abstract we propose to carry out with isophot a spatially resolved study of the dust distribution in the disks of different archetypes of spiral galaxies, and thereby investigate the spatial distribution of star formation spontaneous and triggered in relation to the optical image and to the spiral pattern, i.e. to the dynamical properties of the galaxy (density waves, bars, etc.). in order to discriminate dust components of different temperatures we will perform the observations in several colors from 25 to 160 um. observation strategy in this subproposal 5 spirals will be mapped with p2, c100 and c200, using the aots p03 and p32, with filters at 25, 60, 100, and 160um. m101 will be mapped with p32 over an area of 24.x24.: oversampling factor is 3/2 for c100, 15x20 raster steps, integration times are 32sec at 60um,16sec at 100um. oversampling for c200 is 2, 15x30 step are needed, integration time at 160um is 8sec. for the p2 detector, only the central area of 11.x11. will be mapped with aot p03 in raster staring mode: filter 25um, aperture 52, 13x13 steps with raster step size of 52; integration time 32sec. for the outer regimes sparse mapping will be done (aot p1719) with identical aperture and integration time. additional data at 25um will be available from from sparse maps done in project iso424 (star formation in disk hii regions, proposed by hippelein et al.). m51 will be mapped within an area of 15.x15., which needs 10x13 raster steps for c100 (oversampling 3/2, integration times 32sec at 60um, 16sec at 100um), and 10x20 raster points for c200 (integration time 8sec). m83 will be done over the same area and with the same number of raster points, but with integration times of 16, 8, and 8sec at 60, 100 and 160um, respectively. m94 will be mapped with c100 and c200 over an area of 7.x7.: 5x7 raster points for c100, with intergation times 32sec at 60um and 16sec at 100um; 5x10 raster poi truncat [truncated!, Please see actual data for full text]