Variable Hα Emission in the Nebular Spectra of the Low-luminosity Type Ia SN2018cqj/ATLAS18qtd
Variable Hα Emission in the Nebular Spectra of the Low-luminosity Type Ia SN2018cqj/ATLAS18qtd
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DOI：
10.3847/1538-4357/ab6323
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
J. Prieto;Ping Chen;S. Dong;S. Bose;A. Gal-yam;T. Holoien;J. Kollmeier;M. Phillips;B. Shappee
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文献类型：
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作者：
J. Prieto;Ping Chen;S. Dong;S. Bose;A. Gal-yam;T. Holoien;J. Kollmeier;M. Phillips;B. Shappee
介绍了Ia型超新星SN 2018 cqj/ATLAS 18 qtd的光度学和光谱学。这颗超新星在一个孤立的区域爆发，距离S 0星系IC 550 z = 0.0165（D = 74 Mpc），红移与该星系的物理关联一致。多色测光显示，SN 2018 cqj/ATLAS 18 qtd是一个低光度（mag），快速下降的Ia型，色伸缩sBV为<$0.6，B带下降率Δm15（B）为<$1.77等。作为100 IAS巡天的一部分，在+193和+193处获得了两个星云相位谱。在峰值后307天，清晰地探测到一条窄的Hα发射线，在第一个光谱中分辨出，半高宽为<$1200 km s−1，LHα为<$3.8 × 1037 erg s−1。探测到一条亮度下降的Hα谱线与最近的模型基本一致，在该模型中，氢从单简并祖先系统的非简并伴星中剥离。然而，与Hα线的光度一致的氢的量将是1010 −3 M <$，这明显低于经典单简并祖先系统的理论模型预测。SN 2018 cqj/ATLAS 18 qtd是继SN 2018 fhw/ASASSN-18 tb之后第二个低光度、快速衰减的Ia型超新星，在其星云相光谱中显示出窄的Hα发射。
We present optical photometry and spectroscopy of the Type Ia supernova SN2018cqj/ATLAS18qtd. The supernova exploded in an isolated region at ∼65 kpc from the S0 galaxy IC 550 at z = 0.0165 (D ≈ 74 Mpc) and has a redshift consistent with a physical association to this galaxy. Multicolor photometry show that SN2018cqj/ATLAS18qtd is a low-luminosity ( mag), fast-declining Type Ia, with color stretch sBV ≈ 0.6 and B-band decline rate Δm15(B) ≈ 1.77 mag. Two nebular-phase spectra obtained as part of the 100IAS survey at +193 and +307 days after peak show the clear detection of a narrow Hα line in emission that is resolved in the first spectrum with FWHM ≈ 1200 km s−1 and LHα ≈ 3.8 × 1037 erg s−1. The detection of a resolved Hα line with a declining luminosity is broadly consistent with recent models where hydrogen is stripped from the nondegenerate companion in a single-degenerate progenitor system. However, the amount of hydrogen consistent with the luminosities of the Hα line would be ∼10−3 M⊙, which is significantly less than theoretical model predictions in the classical single-degenerate progenitor systems. SN2018cqj/ATLAS18qtd is the second low-luminosity, fast-declining SN Ia after SN2018fhw/ASASSN-18tb that shows narrow Hα in emission in its nebular-phase spectra.