ZTF SN~Ia DR2：来自超新星同胞的Ia型超新星标准化的宇宙学无关约束
ZTF SN~Ia DR2: Cosmology-independent constraints on Type Ia supernova standardisation from supernova siblings
AI总结：
本研究利用ZTF观测的25对Ia型超新星同胞样本，在不依赖宇宙学模型的前提下推导其标准化参数，发现本征散射极小，且宽度-光度关系斜率α高于宇宙学样本，或与不同衰减速率的超新星差异有关。
摘要：
理解Ia型超新星（SNe~Ia）以及使其成为优秀距离指示器的经验标准化关系，对于改进宇宙学约束至关重要。Ia型超新星“同胞”，即位于同一宿主星系或母星系中的两颗及以上Ia型超新星，为推断标准化关系及其在种群中的多样性提供了独特途径。我们分析了由兹威基瞬变工厂（Zwicky Transient Factory，ZTF）均匀观测的25个Ia型超新星对样本，以推断Ia型超新星光变曲线宽度-光度与颜色-光度参数$α$和$β$。利用来自同胞的成对约束，考虑到标准化关系的多样性，我们得出$α= 0.218 \u00b1 0.055$、$β= 3.084 \u00b1 0.312$，在95%置信水平下，$α$和$β$的离散度分别为$\u2264 0.195$和$\u2264 0.923$。虽然中位离散度较大，但在~1σ范围内的数值与无离散度的情况一致。因此，通过拟合单一全局标准化关系，我们得到$α= 0.228 \u00b1 0.029$、$β= 3.160 \u00b1 0.191$。我们发现同胞样本的本征散射非常小，在95%置信水平下$σ_{\rm int} \u2264 0.10$，而在不将其作为同胞对比较、仅用哈勃残差计算散射时，$σ_{\rm int} = 0.22 \u00b1 0.04$。按宿主星系恒星质量拆分样本后，我们发现两个子样本中的Ia型超新星具有一致的$α$和$β$。其$β$值与宇宙学样本的数值一致，但我们发现$α$值高出~2.5-3.5σ。较高的$α$由低$x_1$的超新星对主导，这可能表明衰减速度慢和快的Ia型超新星具有不同的宽度-光度关系斜率。我们可以通过未来时域巡天增加的统计量来证实或反驳这一点。
英文摘要：
Understanding Type Ia supernovae (SNe~Ia) and the empirical standardisation relations that make them excellent distance indicators is vital to improving cosmological constraints. SN~Ia ``siblings", i.e. two or more SNe~Ia in the same host or parent galaxy offer a unique way to infer the standardisation relations and their diversity across the population. We analyse a sample of 25 SN~Ia pairs, observed homogeneously by the Zwicky Transient Factory (ZTF) to infer the SNe~Ia light curve width-luminosity and colour-luminosity parameters $α$ and $β$. Using the pairwise constraints from siblings, allowing for a diversity in the standardisation relations, we find $α= 0.218 \pm 0.055 $ and $β= 3.084 \pm 0.312$, respectively, with a dispersion in $α$ and $β$ of $\leq 0.195$ and $\leq 0.923$, respectively, at 95$\%$ C.L. While the median dispersion is large, the values within $\sim 1 σ$ are consistent with no dispersion. Hence, fitting for a single global standardisation relation, we find $α= 0.228 \pm 0.029 $ and $β= 3.160 \pm 0.191$. We find a very small intrinsic scatter of the siblings sample $σ_{\rm int} \leq 0.10$ at 95\% C.L. compared to $σ_{\rm int} = 0.22 \pm 0.04$ when computing the scatter using the Hubble residuals without comparing them as siblings. Splitting the sample based on host galaxy stellar mass, we find that SNe~Ia in both subsamples have consistent $α$ and $β$. The $β$ value is consistent with the value for the cosmological sample. However, we find a higher $α$ by $\sim 2.5 - 3.5 σ$. The high $α$ is driven by low $x_1$ pairs, potentially suggesting that the slow and fast declining SN~Ia have different slopes of the width-luminosity relation. We can confirm or refute this with increased statistics from near future time-domain surveys. (abridged)
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
