A new formulation of the Type Ia supernova rate and its consequences on galactic chemical evolution
- Author(s)
- Francesca Matteucci, N Panagia, A Pipino, F Mannucci, Simone Recchi, M. Della Valle
- Abstract
In recent papers, Mannucci et al. and Mannucci, Della Valle & Panagia suggested, on the basis of observational arguments, that there is a bimodal distribution of delay times for the explosion of Type la supernovae (SNe). In particular, a percentage from 35 to 50 per cent of the total Type la SNe should be composed by systems with lifetimes as short as 108 yr, whereas the rest should arise from smaller mass progenitors with a much broader distribution of lifetimes. In this paper, we test this hypothesis in models of chemical evolution of galaxies of different morphological type: ellipticals, spirals and irregulars. We show that this proposed scenario is compatible also with the main chemical properties of galaxies. In this new formulation, we simply assume that Type la SNe are originating from C-O white dwarfs in binary systems without specifying if the progenitor model is the single-degenerate or the double-degenerate one or a mixture of both. In the framework of the single-degenerate model, such a bimodal distribution of the time delays could be explained if the binary systems with a unitary mass ratio are favoured in the mass range 5-8 M?, whereas for masses -2.0 dex, relative to the old models. For a typical elliptical of 1011 M? of luminous mass, the new rate produces average [a/Fe] ratios in the dominant stellar population still in agreement with observations. The Type la SN rate also in this case shows an earlier peak and a subsequent faster decline relative to the previous results, but the differences are smaller than in the case of our Galaxy. We have also checked the effects of the new Type la SN rate on the evolution of the Fe content in the intracluster medium (ICM), as a consequence of its production from cluster ellipticals and we found that less Fe in the ICM is produced with the new rate, due to the higher fraction of Fe synthesized at early times and remaining locked into the stars in ellipticals. For dwarf irregular galaxies suffering few bursts of star formation, we obtain [O/Fe] ratios larger by 0.2 dex relative to the previous models. Π2006 RAS.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Università degli Studi di Trieste, Space Telescope Science Institute, INAF - Osservatorio Astrofisico di Arcetri
- Journal
- Monthly Notices of the Royal Astronomical Society
- Volume
- 372
- Pages
- 265-275
- No. of pages
- 11
- ISSN
- 0035-8711
- Publication date
- 2006
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/7099bdb0-78a5-40f8-beab-4f69257ed5f9