The fir/radio correlation in starburst galaxies - constraints on starburst models
May, 1996Citations per year
Abstract: (arXiv)
This paper presents an analysis of the correlation between the far-infrared (FIR) and the radio emission of starburst galaxies. Data for interacting galaxies, many of which are undergoing a starburst, and for normal galaxies have been analysed and compared in order to test for any influence of the star-formation activity on the ratio between the FIR and the radio emission at 2.4 GHz, \q24. No statistically significant indication for such an influence has been found: There is neither a significant difference between \q24 of the two samples nor a dependence of this ratio on the starburst strength. This observational fact is unexpected because of the different physical conditions and the short time-scale of the star-formation activity in a starburst. In order to interprete the observations the FIR and the radio emission during a starburst have been modeled. The following conclusions could be drawn from the observed constancy of \q24: A strong and fast ( yr) increase of the magnetic field at the beginning of the starburst is required in order to maintain a constant \q24. Otherwise the strong Inverse Compton losses that are due to the intense radiation field in a starburst would lower the synchrotron emission drastically resulting in a value of \q24 significantly higher than the observed one. Furthermore, the time-scale of the variation of the star-formation rate has to be longer than some yr. For lower values the different time-scales of the FIR and the radio emission produce large fluctuations of \q24.References(0)
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