Simultaneous polarization monitoring of supernovae SN 2008D/XT 080109 and SN 2007uy: isolating geometry from dust
Simultaneous polarization monitoring of supernovae SN 2008D/XT 080109 and SN 2007uy: isolating geometry from dust
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超新星 SN 2008D/XT 080109 和 SN 2007uy 的同步偏振监测：将几何结构与尘埃隔离
DOI：
10.1051/0004-6361/200913263
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发表时间：
2008
影响因子：
6.5
通讯作者：
France.
中科院分区：
文献类型：
--
作者：
J. Gorosabel;A. U. Postigo;A. Castro‐Tirado;I. Agudo;M. Jelínek;S. Léon;T. Augusteijn;J. Fynbo;J. Hjorth;M. Michałowski;D. Xu;P. Ferrero;D. A. Kann;S. Klose;A. Rossi;J. Madrid;Á. Llorente;M. Bremer;J. M. I. D. A. D. Andalucia;Granada;S. Eso;Chile. INAFOABr;Italy Iram;S. Alma;Chile. Not;L. Palma;S. Dark;D. Iac;Spain Univ. of La Laguna;Spain. Tls;Tautenburg;Germany. Swinburne Univ. of Tech.;Hawthron;Australia. Insa;Herschel Science Centre;Madrid;S. Iram;France.
上下文。从普通超新星（SNe，没有任何相对论性流出的迹象）到与高能长时间伽玛射线暴（grb）相关的相对论性超新星，是否存在一个包含各种爆炸性恒星死亡的连续体，正在引起激烈的争论。在这种背景下，超新星SN 2008D与x射线瞬变（XT） 080109相关联可能是一个典型的例子，因为它可能是一个潜在的边界跃变事件的例子。光学偏振学研究有助于阐明文献中对这颗超新星（以下简称SN 2008D/XT 080109）的不同解释。目标。主要目的是通过研究SN 2008D/XT 080109的线偏振演化来推断其几何信息。我们还报道了SN 2007uy的偏振演化，并讨论了宿主星系星际介质（ISM）对XT的特性。最后的目标是比较两个SNe的偏振特性，从而比较它们的几何形状。方法。本文对在NGC 2770中同时发光数周的SN 2008D/XT 080109和SN 2007y进行了v波段线性偏振监测。这个幸运的巧合使我们有机会同时观察这两个物体，最重要的是，使用相同的仪器设置。观测跨度为74.9天，从XT后3.6天开始，分布在11次访问中。此外，我们进行了毫米（mm）范围内的观测，以确定观测到的偏振的主要来源。结果。我们报道了SN 2008D/XT 080109在几个时期以~ 1%的水平检测到正线性极化。对于SN 2007y，测量到的极化约为~ 1.5%。在这两种情况下，观测到的线偏振似乎都受到宿主星系星际偏振（HGIP）的支配，尤其是在SN 2007uy的情况下。SN 2007uy的Stokes参数与无时间演化一致，可以用HGIP加上天平面上恒定的偏心膨胀来描述。在对SN 2007uy的观测过程中，我们发现它的总极化信号变化不超过0.29%，置信区间为90%。尽管HGIP占主导地位，但对SN 2008D/XT 080109 Stokes参数分布的统计分析表明，它可能显示出一种可能的本征变极化成分。此外，假设来自SN 2007uy的极化信号是恒定的，我们发现SN 2008D/XT 080109本征极化的时间演化可以用变偏心距的非球面轴对称展开来解释，尽管其他更复杂的几何场景也与数据兼容。即使我们对SN 2007y Stokes参数不做任何假设，我们也得到了同样的结果，尽管显著性水平较低。结论。我们的结论是，这些数据似乎表明SN 2008D/XT 080109有一个潜在的对称轴，当SN 2007y被假设为具有恒定的斯托克斯参数并被用作参考星时，这一对称轴得到了加强。我们认为，SN 2008D/XT 080109和SN 2007y的投影几何形状（如果不是内在几何形状的话）可能是不同的。
Context. The possible existence of a continuum encompassing the diversity of explosive stellar deaths, ranging from ordinary supernovae (SNe; lacking any sign of a relativistic outflow) to relativistic hypernovae associated with energetic long duration gamma-ray bursts (GRBs), is under intense debate. In this context, the supernova SN 2008D associated with the X-ray transient (XT) 080109 could represent a paradigmatic case, since it might exemplify a potential borderline transition event. Optical polarimetric studies could contribute to shed light on the different interpretations given in the literature for this supernova (hereafter, SN 2008D/XT 080109). Aims. The main aim is to infer geometric information of SN 2008D/XT 080109 through the study of the evolution of its linear optical polarization. We also report the polarization evolution of SN 2007uy, and discuss the properties of the host galaxy interstellar medium (ISM) towards the XT. The final goal is to compare the polarization properties, and therefore the geometries, of both SNe. Methods. We present a V-band linear polarization monitoring campaign carried out for SN 2008D/XT 080109 and SN 2007uy, which shone for weeks contemporaneously in NGC 2770. This fortunate coincidence brought us the opportunity to observe both objects simultaneously, and most importantly, with identical instrumental setups. The observations span 74.9 days, starting 3.6 days after the XT and are distributed in 11 visits. In addition we performed observations in the millimetre (mm) range in order to identify the dominant origin of the observed polarization. Results. We report positive linear polarization detections at several epochs for SN 2008D/XT 080109 at a level of ∼1%. For SN 2007uy the measured polarization is around ∼1.5%. In both cases the observed linear polarization seems dominated by the host galaxy interstellar polarization (HGIP), especially for the case of SN 2007uy. SN 2007uy shows Stokes parametres consistent with no time evolution, which could be described by the HGIP plus a constant eccentricity expansion on the sky plane. Over the course of our observations of SN 2007uy, we find that its total polarization signal does not change by more than 0.29% with a 90% confidence interval. Despite the dominant HGIP, a statistical analysis of the distribution of the SN 2008D/XT 080109 Stokes parametres suggests that it could show a possible intrinsic variable polarization component. Moreover, assuming the polarization signal from SN 2007uy is constant, we find that the temporal evolution of the intrinsic SN 2008D/XT 080109 polarization could be explained by an aspherical axisymmetric expansion with variable eccentricity, although other more complex geometric scenarios are also compatible with the data. We come to the same result even if we make no assumption on the SN 2007uy Stokes parametres, although at a lower significance level. Conclusions. We conclude that the data seem to suggest a potential symmetry axis for SN 2008D/XT 080109, which is reinforced when SN 2007uy is assumed to have constant Stokes parametres and used as reference star. We suggest that at least the projected, if not the intrinsic, geometry of SN 2008D/XT 080109 and SN 2007uy could be different.
基于互补单开环谐振器 (CSSRR) 的超材料旋转传感器
DOI：
10.1080/09205071.2018.1465480
发表时间：
2018-01-01
影响因子：
1.3
作者：
Rao, Fang;Yu, Zetai;Yang, Helin
通讯作者：
Yang, Helin