CORE-COLLAPSE SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: INDICATIONS FOR A DIFFERENT POPULATION IN DWARF GALAXIES-猫眼课题宝

DOI：

10.1088/0004-637x/721/1/777

发表时间：

2010-04

期刊：

The Astrophysical Journal

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通讯作者：

中科院分区：

其他

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作者：

I. Arcavi;A. Gal-yam;M. Kasliwal;R. Quimby;E. Ofek;S. Kulkarni;P. Nugent;S. Cenko;J. Bloom;M. Sullivan;D. Howell;D. Poznanski;A. Filippenko;N. Law;I. Hook;J. Jönsson;S. Blake;J. Cooke;R. Dekany;G. Rahmer;D. Hale;Roger M. Smith;J. Zolkower;V. Velur;R. Walters;J. Henning;K. Bui;D. McKenna;J. Jacobsen

我们使用 Palomar Transient Factory (PTF) 首次汇编的 72 个核心塌陷超新星 (SNe) 来研究它们在矮星系与巨星系中观察到的亚型分布。我们的样本是有史以来最大的单次调查、无目标、光谱分类、同质的核心塌缩事件集合，跨越了广泛的宿主星系光度范围（低至 Mr ≈ -14 mag），并包括相当一部分（>20%）的矮星（Mr ⩾ -18 mag）宿主。我们在矮星系中发现了比预期更多的核心塌缩超新星，并且出现了一些有趣的趋势。我们使用剥离包层核心塌缩超新星的详细子分类，发现矮星系中发生的所有 I 型核心塌缩事件要么是超新星 Ib，要么是宽线超新星 Ic（超新星 Ic-BL），而“正常”超新星 Ic 在巨星系中占主导地位。我们还发现矮宿主中 SNe IIb 显着过量。我们假设，在金属丰度较低的宿主中，金属丰度驱动的质量损失减少，使得在富含金属的星系中以“正常”超新星 Ic 形式出现的大质量恒星保留了一些 He 和 H，以 Ib/IIb 事件的形式爆炸。与此同时，另一种机制允许一些恒星经历广泛的剥离并以超新星 Ic-BL 的形式爆炸（大概也以长持续时间的伽马射线爆发的形式）。我们的结果仍然受到小数据统计的限制，并且我们对矮星和巨型宿主中观测到的 N(Ib/c)/N(II) 数量比的测量（分别为 0.25+0.3−0.15 和 0.23+0.11−0.08；1σ 不确定性）与之前的研究和理论预测一致。随着额外的 PTF 数据积累，更强大的统计分析将成为可能，从而允许通过矮星系 SN 群体来探测大质量恒星的演化。

We use the first compilation of 72 core-collapse supernovae (SNe) from the Palomar Transient Factory (PTF) to study their observed subtype distribution in dwarf galaxies compared to giant galaxies. Our sample is the largest single-survey, untargeted, spectroscopically classified, homogeneous collection of core-collapse events ever assembled, spanning a wide host-galaxy luminosity range (down to Mr ≈ −14 mag) and including a substantial fraction (>20%) of dwarf (Mr ⩾ −18 mag) hosts. We find more core-collapse SNe in dwarf galaxies than expected and several interesting trends emerge. We use detailed subclassifications of stripped-envelope core-collapse SNe and find that all Type I core-collapse events occurring in dwarf galaxies are either SNe Ib or broad-lined SNe Ic (SNe Ic-BL), while “normal” SNe Ic dominate in giant galaxies. We also see a significant excess of SNe IIb in dwarf hosts. We hypothesize that in lower metallicity hosts, metallicity-driven mass loss is reduced, allowing massive stars that would have appeared as “normal” SNe Ic in metal-rich galaxies to retain some He and H, exploding as Ib/IIb events. At the same time, another mechanism allows some stars to undergo extensive stripping and explode as SNe Ic-BL (and presumably also as long-duration gamma-ray bursts). Our results are still limited by small-number statistics, and our measurements of the observed N(Ib/c)/N(II) number ratio in dwarf and giant hosts (0.25+0.3−0.15 and 0.23+0.11−0.08, respectively; 1σ uncertainties) are consistent with previous studies and theoretical predictions. As additional PTF data accumulate, more robust statistical analyses will be possible, allowing the evolution of massive stars to be probed via the dwarf-galaxy SN population.

CORE-COLLAPSE SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: INDICATIONS FOR A DIFFERENT POPULATION IN DWARF GALAXIES

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