论文标题
从延迟曲线推断出IA型超新星弹出的密度分布的限制
Constraints on the density distribution of type Ia supernovae ejecta inferred from late-time light-curve flattening
论文作者
论文摘要
有限的时间，$τ_ {\ rm dep} $，从$β^{+} $衰减中的$^{56} $ co的positrons中的超级novae ejecta exjecta铅中的能量将能量沉积在positrons型中，以防上限降低了溢流效率下降的速度下降。当弹射密度降至$τ_ {\ rm dep} $等于$^{56} $ co寿命时，显着的光曲线将获得显着的扁平化。我们提供了一种简单的方法来准确描述这种“延迟沉积”效果，该效应很容易用于分析观察到的光曲线。我们发现，射流加热通常是由600〜天的延迟沉积支配，而后来又以更长的寿命同位素$^{57} $ co和$^{55} $ fe衰减（假设太阳丰度）。对于相对狭窄的$^{56} $ ni速度分布的常用爆炸模型，光曲线的修改主要取决于$^{56} $ ni大规模加权平均密度，$ \ langleρ\ rangleρ\ rangle t^{3} $。因此，可以通过确定$ \ langleρ\ rangleρ\ rangle t^3 $（以及$^{57} $ co and $^{555} $ fe burances），可以通过JWST Far-Infrared（Far-Ir）测量获得准确的延迟降压曲线，可以通过JWST FARFRADER（FAR-IR）测量获得。从最近的观察结果推断出的光曲线的扁平曲线（由于缺乏FAR-IR数据而尚不确定）很容易通过$ \ langleρ\ rangle t^{3} \ langleρ\ rangle t^{3} \ of 0.2 \，m _ {\ odot} \ odot} \，（10^4} {4} {4} {4} {4} {4} \，（ \ textrm {km} \，\ textrm {s}^{ - 1}）^{ - 3} $，并不意味着SuperSolar $^{57} $ CO和$^{55} $ fe bundances。
The finite time, $τ_{\rm dep}$, over which positrons from $β^{+}$ decays of $^{56}$Co deposit energy in type Ia supernovae ejecta lead, in case the positrons are trapped, to a slower decay of the bolometric luminosity compared to an exponential decline. Significant light-curve flattening is obtained when the ejecta density drops below the value for which $τ_{\rm dep}$ equals the $^{56}$Co life-time. We provide a simple method to accurately describe this "delayed deposition" effect, which is straightforward to use for analysis of observed light curves. We find that the ejecta heating is dominated by delayed deposition typically from 600 to 1200~day, and only later by longer lived isotopes $^{57}$Co and $^{55}$Fe decay (assuming solar abundance). For the relatively narrow $^{56}$Ni velocity distributions of commonly studied explosion models, the modification of the light curve depends mainly on the $^{56}$Ni mass-weighted average density, $\langle ρ\rangle t^{3}$. Accurate late-time bolometric light curves, which may be obtained with JWST far-infrared (far-IR) measurements, will thus enable to discriminate between explosion models by determining $\langle ρ\rangle t^3$ (and the $^{57}$Co and $^{55}$Fe abundances). The flattening of light curves inferred from recent observations, which is uncertain due to the lack of far-IR data, is readily explained by delayed deposition in models with $\langle ρ\rangle t^{3} \approx 0.2\,M_{\odot}\,(10^{4}\, \textrm{km}\,\textrm{s}^{-1})^{-3}$, and does not imply supersolar $^{57}$Co and $^{55}$Fe abundances.
