GRB 020813：平滑光学衰减中的偏振
天体物理学
2008-11-26 v2
摘要
我们报告对GRB 020813光学后glow进行VLT极化监测，持续三晚，从0.88到4.20天后。我们 campaign的结果为<P>=1.18+/-0.10%，纠正Galactic星际偏振后Theta = 148.7+/-2.3 deg。我们的VLT数据集最自然地描述为恒定的线性偏振程度和位置角，但Theta的缓慢演化不能完全被数据排除。VLT监测campaign未发现显著的Theta旋转，相对于Keck在GRB后约0.25天进行的光谱极化观测（Barth等人2003）。然而，<P>的值比Keck测得的偏振程度低约为一倍。此外，VLT极化数据允许我们构建精确的V-band光度曲线。V-band光度数据揭示了一条光滑的光度曲线，在最后一次Keck观测与我们第一次VLT极化测量之间出现一个break，0.33 < t_(break, V) < 0.88天后。V-band光度曲线的典型magnitude波动分别为0.003 mag, 0.010 mag和0.016 mag。我们推测，Theta的稳定性可能与光度曲线的平滑性有关。
引用
@article{arxiv.astro-ph/0309748,
title = {GRB 020813: polarization in the case of a smooth optical decay},
author = {J. Gorosabel and E. Rol and S. Covino and A. J. Castro-Tirado and J. M. Castro Cerón and D. Lazzati and J. Hjorth and D. Malesani and M. Della Valle and S. di Serego Alighieri and F. Fiore and A. S. Fruchter and J. P. U. Fynbo and G. Ghisellini and P. Goldoni and J. Greiner and G. L. Israel and L. Kaper and N. Kawai and S. Klose and C. Kouveliotou and E. Le Floc'h N. Masetti and F. Mirabel and P. Moller and S. Ortolani and E. Palazzi and E. Pian and J. Rhoads and G. Ricker and P. Saracco and L. Stella and G. Tagliaferri and N. Tanvir and E. van den Heuvel and M. Vietri and P. M. Vreeswijk and R. A. M. J. Wijers and F. M. Zerbi},
journal= {arXiv preprint arXiv:astro-ph/0309748},
year = {2008}
}
备注
7 pages, 2 figures, accepted for publication in A&A. Minor changes included with respect to the previously posted version