The Earliest Stage of Galactic Star Formation

Star Formation Histories of the Galactic Satellites

Late accretion models for formation of the Galactic halo require that many Galactic satellite galaxies have been cannibalised into the halo field. Comparison of the metallicity and age distribution function of stars in the surviving satellites with the apparently exclusively old stars in the field halo can constrain the importance of any such process. We have developed a new objective technique...

Star Formation and Galactic Evolution

The New Frontier: Galactic–Scale Star Formation

The arena of investigation of star formation and its scaling laws is slowly, but consistently, shifting from the realm of luminous galaxies to that of faint ones and to sub–galactic regions, as existing and new facilities enable investigators to probe regions of the combined parameter space of surface brightness, wavelength, and angular resolution that were inaccessible until a few years ago. W...

Star Formation Thresholds in Galactic Disks

We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H2 (as traced by CO) surface density profiles, and new Hα CCD photometry. In this paper we present an atlas of Hα images and radial surface brightness profiles and describe a surface-density threshold in the star formation law. Prominent b...

Implications for the formation of star clusters from extra-galactic star-formation rates

Observations indicate that young massive star clusters in spiral and dwarf galaxies follow a relation between luminosity of the brightest young cluster and the star-formation rate (SFR) of the host galaxy, in the sense that higher SFRs lead to the formation of brighter clusters. Assuming that the empirical relation between maximum cluster luminosity and SFR reflects an underlying similar relati...