The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system
The evolution of superluminous supernova LSQ14mo and its interacting host galaxy system
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DOI：
10.1051/0004-6361/201630163
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发表时间：
2016-11
影响因子：
6.5
通讯作者：
T. W. Chen;T. W. Chen;M. Nicholl;S. Smartt;P. Mazzali;P. Mazzali;R. Yates;T. Moriya;C. Inserra;N. Langer;T. Krühler;Yen-Chen Pan;R. Kotak;L. Galbany;P. Schady;P. Wiseman;J. Greiner;S. Schulze;Allison Man;A. Jerkstrand;K. Smith;M. Dennefeld;C. Baltay;J. Bolmer;J. Bolmer;E. Kankare;F. Knust;K. Maguire;D. Rabinowitz;S. Rostami;Mark Sullivan;D. Young
中科院分区：
文献类型：
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作者：
T. W. Chen;T. W. Chen;M. Nicholl;S. Smartt;P. Mazzali;P. Mazzali;R. Yates;T. Moriya;C. Inserra;N. Langer;T. Krühler;Yen-Chen Pan;R. Kotak;L. Galbany;P. Schady;P. Wiseman;J. Greiner;S. Schulze;Allison Man;A. Jerkstrand;K. Smith;M. Dennefeld;C. Baltay;J. Bolmer;J. Bolmer;E. Kankare;F. Knust;K. Maguire;D. Rabinowitz;S. Rostami;Mark Sullivan;D. Young
我们展示并分析了超光度超新星 (SLSN) LSQ14mo (z = 0.256) 的广泛数据集，其中包括静止帧中从 -30 d 到 +70 d 的多色光曲线（相对于最大光）以及来自 PESSTO 的一系列覆盖 -7 d 到 +50 d 的六个光谱。对于快速下降的贫氢 SLSN，这是最密集的光谱覆盖范围和最佳约束的上升光曲线之一。辐射热光曲线可以用喷射质量约为 4 M⊙ 的毫秒磁星模型来重现，并且温度和速度演化也表明磁星作为动力源。光谱模型表明，SN 喷射出约 6 M⊙ 的富含 CO 的物质，动能约为 7 × 1051 erg，并表明在 -2 d 和 +22 d 之间存在部分热化的额外光度源。这可能是由于与源自爆炸前质量损失的材料壳的相互作用。我们进一步对 LSQ14mo 的宿主星系系统进行了详细分析。 PESSTO 和 GROND 成像显示了三个空间分辨的明亮区域，我们使用 VLT 和 FORS2 获得了 SN 位置和三个恒星形成区域的深（五小时曝光）光谱，它们具有相似的红移。 + 300 天的 FORS2 光谱显示没有 SN 发射线的痕迹，并且通过与其他 Ic 超新星的比较，我们对 [O i] 的强度进行了限制。深光谱为研究宿主恒星形成活动和金属丰度的空间变化提供了独特的机会。所有三个组成部分的特定恒星形成率相似，年轻恒星群体的存在也是相似的。然而，LSQ14mo 的位置表现出较低的金属丰度，在 R23 和 N2 尺度上均为 12 + log (O/H) = 8.2（对应于~0.3 Z⊙ ）。我们认为宿主系统中的三个明亮区域正在相互作用，这可能会引起气流，从而触发低金属区域中的恒星形成。
We present and analyse an extensive dataset of the superluminous supernova (SLSN) LSQ14mo (z = 0.256), consisting of a multi-colour light curve from −30 d to +70 d in the rest-frame (relative to maximum light) and a series of six spectra from PESSTO covering −7 d to +50 d. This is among the densest spectroscopic coverage, and best-constrained rising light curve, for a fast-declining hydrogen-poor SLSN. The bolometric light curve can be reproduced with a millisecond magnetar model with ~ 4 M⊙ ejecta mass, and the temperature and velocity evolution is also suggestive of a magnetar as the power source. Spectral modelling indicates that the SN ejected ~ 6 M⊙ of CO-rich material with a kinetic energy of ~7 × 1051 erg, and suggests a partially thermalised additional source of luminosity between −2 d and +22 d. This may be due to interaction with a shell of material originating from pre-explosion mass loss. We further present a detailed analysis of the host galaxy system of LSQ14mo. PESSTO and GROND imaging show three spatially resolved bright regions, and we used the VLT and FORS2 to obtain a deep (five-hour exposure) spectra of the SN position and the three star-forming regions, which are at a similar redshift. The FORS2 spectrum at + 300 days shows no trace of SN emission lines and we place limits on the strength of [O i] from comparisons with other Ic supernovae. The deep spectra provides a unique chance to investigate spatial variations in the host star-formation activity and metallicity. The specific star-formation rate is similar in all three components,as is the presence of a young stellar population. However, the position of LSQ14mo exhibits a lower metallicity, with 12 + log (O/H) = 8.2 in both the R23 and N2 scales (corresponding to ~0.3 Z⊙ ). We propose that the three bright regions in the host system are interacting, which could induce gas flows triggering star formation in low-metallicity regions.