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Massive stars (>20 Msun) evolve into Wolf-Rayet
stars with strong winds which produce broad HeII emission lines. The
ultimate death of these stars via core-collapse are though to be
responsible for the production of Type Ib/c supernova, a subject
that has wider relevance as local Gamma-Ray Bursts have been
associated with Type Ic SNe.
Here I briefly discuss the evolution of massive stars and present
VLT/FORS imaging of NGC 7793, a grand design spiral galaxy
containing many HII regions in which WR signatures have fortuitously
been detected.
I present VLT/FORS imaging of NGC 7793 and describe our narrow-band
method of identifying candidate WR regions along with follow up
multi-object spectroscopy to further classify the WR into their
nitrogen-rich (WN) or carbon/oxygen-rich (WC/WO) sub-types. In
addition, we use broad band imaging to determine the N(WR)/N(O) star
ratio as a function of metallicity and compare to those predicted
from evolutionary synthesis models. |
