论文标题
Galaxy簇中类型超新星的延迟时间分布：扩展的恒星形成历史的影响
The delay time distribution of Type-Ia supernovae in galaxy clusters: the impact of extended star-formation histories
论文作者
论文摘要
IA型超新星（SNE IA）的延迟时间分布（DTD）对于理解化学进化，SN IA祖细胞和SN IA物理学很重要。已经从在各种红移下观察到的群集样品中测得的SN IA速率推导了Galaxy簇中DTD的过去估计值，这对应于假定的初始恒星形成后的不同时间间隔。从$ z = 1.13-1.75 $的簇样本进行的最新分析确认了先前对下部降低簇的研究的迹象，即DTD具有幂律形式，$ {\ rm dtd}（t）= r_1（t/{t/{\ rm gyr}）^lime times $ r_1 $ r_1 $ t = 1 $ t = 1野外气候环境。这暗示着SNE IA是群集中的恒星种群以某种方式生产的。然而，这个结论可能受到隐含假设的影响，即恒星是在高$ z $的单个简短的星空中形成的。在这里，我们从群集sn ia数据中重新启用了DTD，但是放松了单爆的假设。取而代之的是，我们允许为每个集群提供一系列恒星形成历史和尘埃灭绝。通过MCMC建模，我们使用出色的种群合成模型和DTD模型同时拟合，在几个频段中的集成星系光度法以及在每个群集中发现的SN IA数字。有了这些更现实的假设，我们找到了具有幂律索引$α= -1.09 _ { - 0.12}^{+0.15} $的最佳拟合DTD，以及幅度$ r_1 = 0.41 = 0.41 _ { - 0.10}^{+0.12}^{+0.12}} yr}^{ - 1} {\ rm m} _ \ odot^{ - 1} $。我们通过因子$ \ sim2-3 $（$3.8σ$）确认了比野外DTD更大的振幅的集群环境DTD。群集和场DTD的一致斜率约为$α\ 1.1 $。
The delay time distribution (DTD) of Type-Ia supernovae (SNe Ia) is important for understanding chemical evolution, SN Ia progenitors, and SN Ia physics. Past estimates of the DTD in galaxy clusters have been deduced from SN Ia rates measured in cluster samples observed at various redshifts, corresponding to different time intervals after a presumed initial brief burst of star formation. A recent analysis of a cluster sample at $z=1.13-1.75$ confirmed indications from previous studies of lower-redshift clusters, that the DTD has a power-law form, ${\rm DTD}(t)=R_1 (t/{\rm Gyr})^α$, with amplitude $R_1$, at delay $t=1~\rm Gyr$, several times higher than measured in field-galaxy environments. This implied that SNe Ia are somehow produced in larger numbers by the stellar populations in clusters. This conclusion, however, could have been affected by the implicit assumption that the stars were formed in a single brief starburst at high $z$. Here, we re-derive the DTD from the cluster SN Ia data, but relax the single-burst assumption. Instead, we allow for a range of star-formation histories and dust extinctions for each cluster. Via MCMC modeling, we simultaneously fit, using stellar population synthesis models and DTD models, the integrated galaxy-light photometry in several bands, and the SN Ia numbers discovered in each cluster. With these more-realistic assumptions, we find a best-fit DTD with power-law index $α=-1.09_{-0.12}^{+0.15}$, and amplitude $R_1=0.41_{-0.10}^{+0.12}\times 10^{-12}~{\rm yr}^{-1}{\rm M}_\odot^{-1}$. We confirm a cluster-environment DTD with a larger amplitude than the field-galaxy DTD, by a factor $\sim2-3$ (at $3.8σ$). Cluster and field DTDs have consistent slopes of $α\approx-1.1$.
