Massive star formation in external galaxies: new giant HII regions

V.FIRPO, G. BOSCH, N. MORRELL.

Cariló. Argentina

Workshop; International Conference: Massive Stars. Fundamental Parameters and Circumstellar Interactions; 2006

FCAGLP

Giant HII Regions (GHIIR) provide the link between the formation of massive stars at smaller scales and the violent processes of star formation that happen in starburst galaxies. This work aims to discover the presence of GHIIR in  spiral and blue compact dwarf (BCD) galaxies and to analyze the properties of the ionized gas in order to determine the nature and evolutionary state of its source of energy. We have obtained data of several luminous HII regions  using  the Magellan Inamori Kyocera  Echelle Spectrograph  (MIKE) at  the Clay  Magellan Telescope and Wide-Field CCD (WFCCD) camera at the 100-inch du Pont telescope (LCO). We have identified the giant nature of candidate  regions and we have determined temperatures, densities and chemical abundances of the ionised gas. These giant HII regions lie, within errors, on the already observed regression in the L-sigma plane.