The large number of galaxies at high redshifts (z) undergoing intense star-formation (Steidel et al. 1996; Lowenthal et al. 1997) suggest starburst galaxies were a dominant phase of early galaxy evolution. While the rate and specific intensity of star formation in these distant galaxies is certainly higher than typical, nearby starbursts (Weedman et al. 1999), local starbursts are similar to star-forming high-z galaxies in terms of their structural and stellar characteristics (Giavalisco et al. 1996; Hibbard & Vacca 1997; Heckman et al. 1998; Conselice et al. 2000a).
Related issues include determining how starbursts are triggered, and if the triggering mechanisms change with z. Starburst triggering mechanisms include: interactions and mergers (Schweizer 1987; Jog & Das 1992), bar instabilities (Shlosman et al. 1990), and kinematic effects from SNe and stellar winds (e.g. Heckman et al. 1990). While the merging is expected to be more common at earlier epochs, the first epoch of star-formation could occur as a result of the inital collapse of individual gas clouds.
For nearby, luminous galaxies, usually it is possible to determine what triggers a starburst by examining kinematic, and pan-chromatic structural information. This can be quite expensive in telescope time, particularly for high-z starbursts, where detailed spectroscopic information is difficult to obtain at present. While some starbursts are undergoing interactions or mergers, it is difficult to quantify the strength and youth of such events. A method of determining starburst triggers based on morphology or other, easily observable properties of a galaxy would be ideal. In this paper we present a method to determine objectively if a starburst is triggered by a galaxy interaction based on its color and R-band asymmetry.
© European Southern Observatory (ESO) 2000
Online publication: January 31, 2000