ISOCAM images at 6.75mu M and 15mu m: the circumnuclear region of NGC4321 (M100)

We present ISOCAM images (1.5\arcsec px(-1) ) in the LW2 (6.75mu m) and LW3 (15mu m) broad band filters of the circumnuclear starburst of NGC4321 (M100). A detailed comparison with the emission at other wavelengths (U, B, Hα , and CO) is also presented. The nature and intensity of the mid-infrared emission is shown to be remarkably different from one star forming region to the next. For instance, star forming regions at the ends of the nuclear bar may contain enshrouded Wolf-Rayet stars. Based on observations with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) on board ISO, an ESA project with the participation of ISAS and NASA.