Carnegie Supernova Project: The First Homogeneous Sample of Super-Chandrasekhar-mass/2003fg-like Type Ia Supernovae-猫眼课题宝

DOI：

10.3847/1538-4357/ac19ac

发表时间：

2021-06

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

C. Ashall;J. Lu;E. Hsiao;P. Hoeflich;M. Phillips;L. Galbany;C. Burns;C. Contreras;K. Krisciunas;N. Morrell;M. Stritzinger;N. Suntzeff;F. Taddia;J. Anais;E. Baron;P. Brown;L. Busta;A. Campillay;S. Castellón;C. Corco;S. Davis;G. Folatelli;F. Förster;W. Freedman;C. González;M. Hamuy;S. Holmbo;R. Kirshner;S. Kumar;G. H. Marion;P. Mazzali;T. Morokuma;P. Nugent;S. E. Persson;A. Piro;M. Roth;F. Salgado;D. Sand;J. Seron;M. Shahbandeh;B. Shappee

我们给出了13颗超Chandrasekhar质量/2003fg类Ia型超新星(SNE Ia)的多波长光度和光谱分析。卡内基超新星计划观测到了其中的九个天体。2003fg类SNE具有缓慢下降的光曲线(Δm 15(B)&lt；1.3mag)和−19&lt；M B&lt；−21mag的B波段峰值。许多2003fg类SNE与正常SNE Ia位于光度-宽度关系的同一部分。在光学B和V波段，类似2003fg的SNE看起来像正常的SNE Ia，但在更红的波长，它们会发散。与其他发光的SNE Ia不同，类似2003fg的SNE Ia通常只有一个I波段峰值，该峰值出现在B波段最大值之后，而它们的近红外(NIR)光曲线上升时间可以比正常的SNE Ia长≳40天。它们在近红外波段的亮度也比正常的SNE Ia至少高1毫克，峰值在MH=−19毫克以上，并且通常有负的哈勃残差，这可能是暗能量实验中一些系统学的原因。从光谱上看，2003fg类SNE的特点是：未燃烧的碳远远超过最大光速，在最大光速下的Si II−6355中有较大的扩展(8 000-12,000公里Sλ1)，没有快速的早期速度下降，+10天没有明显的H带断裂。我们发现，在最大光处具有较大的伪等效宽度的单粒子对撞机具有较低的Si IIλ6355速度和较慢的光衰减曲线。造成2003fg类SNE峰值亮度的因素也是多方面的。C-O简并核在富碳包层内的爆炸与这些观测结果一致。这样的配置可能来自核心退化场景。

We present a multiwavelength photometric and spectroscopic analysis of 13 super-Chandrasekhar-mass/2003fg-like Type Ia supernovae (SNe Ia). Nine of these objects were observed by the Carnegie Supernova Project. The 2003fg-like SNe have slowly declining light curves (Δm 15(B) < 1.3 mag), and peak absolute B-band magnitudes of −19 < M B < −21 mag. Many of the 2003fg-like SNe are located in the same part of the luminosity–width relation as normal SNe Ia. In the optical B and V bands, the 2003fg-like SNe look like normal SNe Ia, but at redder wavelengths they diverge. Unlike other luminous SNe Ia, the 2003fg-like SNe generally have only one i-band maximum, which peaks after the epoch of the B-band maximum, while their near-IR (NIR) light-curve rise times can be ≳40 days longer than those of normal SNe Ia. They are also at least 1 mag brighter in the NIR bands than normal SNe Ia, peaking above M H = −19 mag, and generally have negative Hubble residuals, which may be the cause of some systematics in dark-energy experiments. Spectroscopically, the 2003fg-like SNe exhibit peculiarities such as unburnt carbon well past maximum light, a large spread (8000–12,000 km s−1) in Si ii λ6355 velocities at maximum light with no rapid early velocity decline, and no clear H-band break at +10 days. We find that SNe with a larger pseudo-equivalent width of C ii at maximum light have lower Si ii λ6355 velocities and more slowly declining light curves. There are also multiple factors that contribute to the peak luminosity of 2003fg-like SNe. The explosion of a C–O degenerate core inside a carbon-rich envelope is consistent with these observations. Such a configuration may come from the core-degenerate scenario.

Carnegie Supernova Project: The First Homogeneous Sample of Super-Chandrasekhar-mass/2003fg-like Type Ia Supernovae

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