[论文解读] Multiband Photometry Evolution in the First Weeks of SN 2023ixf, a possible II-L Subtype Supernova

Giorgio Bianciardi, Armand Ciccarelli+9 more|arXiv (Cornell University)|Jul 10, 2023

Gamma-ray bursts and supernovae被引用 7

一句话总结

这篇论文在多台望远镜上对 SN 2023ixf 进行多滤光器摄影测量，显示出快速上升至最大值以及线性、颜色相关的下降，支持其被归类为 II-L 型超新星。

ABSTRACT

Multiband photometric observations and their evaluation to instrumental magnitudes were performed using standard Johnson-Cousins filters (B, V, Rc) as well r and g Sloan filters, and not standard ones (R, G, B, and Clear filters). These were recorded from 9 observatories and from the MicroObservatory Robotic Telescope Network. The results describe the rapid ascent towards the maximum (2.5 magnitudes about in five days in the B filter) and the slow decrease after the maximum (0.0425 +/- 0.02 magnitudes/day in the B filter). The results highlight the strong variation of the B-V colour indices during the first 50 days (from -0.20 +/- 0.02 to +0.85 +/- 0.02) and V-R (from 0 +/- 0.01 to +0.50 +/- 0.01) after the explosion, presumably corresponding to the cooling of the stellar photosphere. At 50 days after the explosion the magnitude decrease from the maximum was observed to continue where it faded by 2.5 magnitudes (B filter), thus we propose SN 2023ixf is a Type II, subtype L, supernova (SNe).

研究动机与目标

• Characterize the early multiband light curve of SN 2023ixf across standard and non-standard filters.
• Quantify rise to maximum and subsequent decline rates in different photometric bands.
• Analyze color evolution (B-V, V-R) to interpret photospheric cooling.
• Assess whether the light-curve decline supports a II-L classification for SN 2023ixf.

提出的方法

• Collect mult observatory photometry using standard Johnson-Cousins B, V, Rc, and Sloan r, g as well as non-standard tri-color filters.
• Perform aperture photometry with MaximDL and use a common reference star (TYC 3852-1108-1) for magnitude calibration where possible.
• Estimate uncertainties (0.002–0.06 mag; mean ~0.02–0.007 mag) across observatories.
• Analyze light-curve rise to maximum and subsequent declines with band-dependent slopes.
• Compute color indices B-V and V-R and fit their evolution over the first ~50 days.

Figure 1: SN 2023ixf occurred in a spiral arm of the Pinwheel Galaxy. This wide-field image was made by one of us on the night of 2023/05/28. The characteristic cyan colour of the supernova near the maximum is well-defined. Reference star is indicated. Image credit: Giuseppe Conzo, UAI Remote Telesc

实验结果

研究问题

• RQ1 在爆发后前50天内，SN 2023ixf 在多种光度带的上升和下降特征是什么？
• RQ2 在早期阶段，颜色指标 (B-V, V-R) 如何演化，它们对光球温度演变有何指示？
• RQ3 该光度行为是否与 II-L（线性下降）型 II 超新星的分类相符？
• RQ4 来自异质仪器和不同滤光组的测量在构建光曲线时的一致性如何？

主要发现

• SN 2023ixf 在 B 波段大约 5 天内迅速上升至最大值约 2.5 等级。
• 最大值后 B 波段下降呈线性，斜率为 0.0425 ± 0.02 mag/day。
• G 波段下降较早开始，斜率为 0.022 ± 0.01 mag/day；R 波段以 0.0187 ± 0.007 mag/day 下降。
• 爆炸后 50 天，B 波段自最大值起下降达到 2.5 等级。
• B-V 从 -0.20 ± 0.02 变化到 +0.85 ± 0.02，V-R 从 0 ± 0.01 变化到 +0.50 ± 0.01，表明光球层正在冷却。
• 观测到的光曲线行为支持将 SN 2023ixf 分类为 Type II-L（线性下降）而非 II-P（平台期）。

Figure 2: This image at a higher resolution than Figure 1 made by one of us shows that SN 2023ixf occurred in a region rich in gas and near several star-forming regions. Image credit: Z. Organić, Orbanić Explorer Observatory.