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The Supernovae Rates

We start with calculation of burst-like  star formation in a galaxy assuming all stars to have been formed simultaneously. Let G(t) be the SN rate in this galaxy after a time period t. Then for any kind of star formation rate history the rate of SN in the galaxy of age t will be

In order to obtain the SN rate, we approximate the SFR in the Universe by a combination of two functions - a tex2html_wrap_inline9046-like SFR of the ``first generation'' stars (presumably ``elliptical galaxies''  with no subsequent star formation) and a constant SFR of the second generation (``spiral galaxies''  with a constant star formation):

Here T is the age of the Universe and is the average density of stars, is the fraction of elliptical galaxies. 

In the Scenario Machine code, we used supernovae types according to the following definitions:

Computation of the evolutionary tracks of tex2html_wrap_inline8905 binaries enabled us to obtain the time evolution of the supernova rate of these 4 types as shown in Figure 51.


Figure 51: The evolution of the SN rate in a sample galaxy after an instantaneous star formation burst  (Jorgensen et al., 1996). 

Mike E. Prokhorov
Sat Feb 22 18:38:13 MSK 1997