高能天体物理研究组知识库

当前的研究表明,在小质量星系或者恒星形成率高的星系中,Ia型超新星有高的诞生率。没有经过光度经验校正,在大质量、高金属丰度、年老的、早型演化的星系中的Ia型超新星更暗;但是经过光度校正以后,亮的超新星更倾向于出现在大质量、高金属丰度、年老的、早型演化的星系中。因为高金属丰度的前身星系统是富中子的,使得在超新星爆发过程中物质更稳定地燃烧,这样产生的56Ni就很少,而56Ni提供的衰变能是Ia型超新星光度的重要来源,会导致高金属丰度环境下的Ia型超新星光变曲线下降更快而且也更暗;但是经过光度校正以后,高金属丰度环境下的Ia型超新星更亮。不同星系环境下的金属丰度不同,因而Ia型超新星56Ni产生率不同,这可能是对超新星光度与星系统计关系的最合理解释。综述了Ia型超新星的诞生率以及光度与寄主星系的统计关系。

We mainly present the dependence of SNe Ia rate and luminosity on their host galaxies. Firstly, we show that the host galaxy mass is lower or host star-formation rate is higher, SNe Ia rate will be larger. Secondly, we show that before light-curve correction, dimmer SNe Ia fluently occur in higher mass, higher star-formation rate, higher metal abundance, or older stellar galaxy system. However, after light-curve correction, brighter SNe Ia fluently occur in higher mass, higher star-formation rate, higher metal abundance, or older stellar galaxy system. Higher-metallicity progenitors are more neutron rich, producing more stable burning products relative to radioactive~( 56)Ni. Since SNe Ia explosions are powered by the radioactive decay~( 56)Ni, it is widely accepted that the intrinsic variation in SNe Ia brightness and decline rate is primarily driven by the amount of~( 56)Ni present in SNe explosion, where more luminous and much slowly declining explosions are powered by more~( 56)Ni, hence, under higher-metallicity circumstances, SNe Ia are dimmer. Whereas, after light-curve correction, SNe Ia in higher-metallicity progenitors are brighter. Therefore, the metallicity diversity is responsible for the dependence of SNe Ia luminosties on host galaxies.