A new method of evaluating relative (arm with respect to the interarm disk) star formation rates and relative star formation efficiencies, together with spiral arm-amplitudes, as a function of the galactocentric radius, using broad-band photometry is derived. The classical method for obtaining star formation rates from Hα photometry is discussed, and a new method is derived for diagnosing the p...

Pixel-by-pixel colour-magnitude and colour-colour diagrams – based on a subset of the Hubble Space Telescope Advanced Camera for Surveys Early Release Observations – provide a powerful technique to explore and deduce the star and star cluster formation histories of the Mice and the Tadpole interacting galaxies. In each interacting system we find some 40 bright young star clusters (20 . F606W(ma...

We present a model for star formation and supernova feedback that describes the multi-phase structure of star forming gas on scales that are typically not resolved in cosmological simulations. Our approach includes radiative heating and cooling, the growth of cold clouds embedded in an ambient hot medium, star formation in these clouds, feedback from supernovae in the form of thermal heating an...

Stars generally form faster than the ambipolar diffusion time, suggesting that several processes short circuit the delay and promote a rapid collapse. These processes are considered here, including turbulence compression in the outer parts of giant molecular cloud (GMC) cores and GMC envelopes, GMC core formation in an initially supercritical state, and compression-induced triggering in dispers...

The OB associations, which are fossil star formation regions, retain the endproducts of the star formation process in an open, unobscured environment. Observations of the low mass stars in OB associations provide a far clearer picture of the results of the star formation process than do observations of embedded, on-going star formation regions. We review the X–ray and optical surveys of the fos...

The Taurus molecular cloud complex is the paradigm for quiescent, low-density, isolated star formation. Yet the age distribution of its stellar population indicates that star formation is a rapid and dynamic process, inconsistent with the old picture of magnetically-controlled protostel-lar cloud collapse. Instead, Taurus seems to have formed stars in a manner qualitatively consistent with the ...