Supernova Yields

Adopting this scenario for the enrichment of the central heavy element abundance peak, one can also study the element abundance ratio in more detail and compare the results with predictions from supernova nucleosynthesis model calculations. The best measured abundances are those of Fe, Si, and O (the latter representing the lighter elements). Thus we will concentrate here on the use of these elements.

In Fig. 23.21 the abundance ratios of Fe/O and Fe/Si are compared for various regions in different groups and clusters of galaxies. In this diagram the Fe/O ratio is a diagnostics of the ratio of Fe yields from SNII and SNIa and the Fe/Si ratio can then be used to test various models of SN Ia yields (introduced by Matsushita et al. [95]). In the plot we have compiled a set of observational results from XMM-Newton, Chandra, and one ASCA result from the literature and compare them to various models with different deflagration speeds for the SN Ia explosion from Nomoto et al. [109] and Iwamoto et al. [79]. The results show that the bulk of the data lay below the curve of the W7 model, which fits the solar abundance and is successfully used to describe the chemical history of our galaxy. The WDD1 and WDD2 models provide yields with larger Si fractions compared to iron than supplied by the W7 model. They better fit the observational data. The data points for M87 are the most extreme in requiring a relatively large Si yield [95]. The possible reason for this is

Fig. 23.21 Ratio of the Fe to Si abundance as a function of the Fe/O abundance ratio (in solar units e.g. [70]) in the ICM of groups and clusters of galaxies [27,42,95,96, 142, 144,161] as determined from Chandra, XMM-Newton, and ASCA observations. Also shown is the abundance ratio of the Sun (asterisk), SN II models (asterisk), abundance of old stars in the Milky Way (box in the lower left) [37,47], and curves indicating the prediction for a mixture of SN II yields and varying contributions from SN Ia for various delayed-deflagration models (WDD1, WDD2, and WDD3) from Iwamoto et al. [79]. For more details see Bohringer et al. [17,18]

Fig. 23.21 Ratio of the Fe to Si abundance as a function of the Fe/O abundance ratio (in solar units e.g. [70]) in the ICM of groups and clusters of galaxies [27,42,95,96, 142, 144,161] as determined from Chandra, XMM-Newton, and ASCA observations. Also shown is the abundance ratio of the Sun (asterisk), SN II models (asterisk), abundance of old stars in the Milky Way (box in the lower left) [37,47], and curves indicating the prediction for a mixture of SN II yields and varying contributions from SN Ia for various delayed-deflagration models (WDD1, WDD2, and WDD3) from Iwamoto et al. [79]. For more details see Bohringer et al. [17,18]

a more incomplete nuclear burning in SN Ia explosions in older stellar populations [60]. This is also consistent with the observed statistically lower luminosity of SN Ia light curves observed in ellitpical galaxies as compared to spirals [78].

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