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arXiv 0803.4017astro-ph
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GRB 070306:一个高度熄灭的余辉

GRB 070306: A Highly Extinguished Afterglow

A. O. Jaunsen, E. Rol, D. J. Watson, D. Malesani, J. P. U. Fynbo, B. Milvang-Jensen, J. Hjorth, P. M. Vreeswijk, J. -E. Ovaldsen, K. Wiersema, N. R. Tanvir, J. … 展开作者

A. O. Jaunsen, E. Rol, D. J. Watson, D. Malesani, J. P. U. Fynbo, B. Milvang-Jensen, J. Hjorth, P. M. Vreeswijk, J. -E. Ovaldsen, K. Wiersema, N. R. Tanvir, J. Gorosabel, A. J. Levan, M. Schirmer, A. J. Castro-Tirado

摘要:

我们报告的高度熄灭余辉的GRB 070306和宿主星系的属性。在爆发的位置没有探测到光学余辉,但在近红外波段,第一个夜晚的亮度加倍,以及后来K波段的幂律衰减提供了清晰的余辉探测。宿主星系相对较亮,R ~ 22.8。一个光学低分辨率光谱揭示了一个很大程度上没有特征的主机星系连续与一个单一的发射线。更高分辨率的后续光谱显示该发射被分辨,并且由两个由7个AA分开的峰组成,表明它是在z = 1.49594 +-0.00006的红移处的[O II]。红外颜色H-K = 2直接揭示了显著的变红。用同步辐射熄灭谱模拟了t = 1.38天时的光学/X射线谱能量分布,得到A_V = 5.5 ± 0.6mag.A_V是迄今为止测量的最大的伽玛暴余辉值之一,超过1的可见光反射是罕见的。早期近红外观测的重要性是显而易见的,可能很快就会为曾经难以捉摸的“黑暗爆发”提供更清晰的视角。

英文摘要:

We report on the highly extinguished afterglow of GRB 070306 and the properties of the host galaxy. An optical afterglow was not detected at the location of the burst, but in near-infrared a doubling in brightness during the first night and later power-law decay in the K band provided a clear detection of the afterglow. The host galaxy is relatively bright, R ~ 22.8. An optical low resolution spectrum revealed a largely featureless host galaxy continuum with a single emission line. Higher resolution follow-up spectroscopy shows this emission to be resolved and consisting of two peaks separated by 7 AA, suggesting it to be [O II] at a redshift of z = 1.49594 +- 0.00006. The infrared color H-K = 2 directly reveals significant reddening. By modeling the optical/X-ray spectral energy distribution at t = 1.38 days with an extinguished synchrotron spectrum, we derive A_V = 5.5 +- 0.6 mag. This is among the largest values ever measured for a GRB afterglow and visual extinctions exceeding unity are rare. The importance of early NIR observations is obvious and may soon provide a clearer view into the once elusive 'dark bursts'.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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