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arXiv 0704.1609astro-ph
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GRB 061121:通过明亮爆发的瞬发和余辉阶段的宽带光谱演变

GRB 061121: Broadband spectral evolution through the prompt and afterglow phases of a bright burst

K. L. Page, R. Willingale, J. P. Osborne, B. Zhang, O. Godet, F. E. Marshall, A. Melandri, J. P. Norris, P. T. O'Brien, V. Pal'shin, E. Rol, P. Romano, R. L. C.… 展开作者

K. L. Page, R. Willingale, J. P. Osborne, B. Zhang, O. Godet, F. E. Marshall, A. Melandri, J. P. Norris, P. T. O'Brien, V. Pal'shin, E. Rol, P. Romano, R. L. C. Starling, P. Schady, S. A. Yost, S. D. Barthelmy, A. P. Beardmore, G. Cusumano, D. N. Burrows, M. De Pasquale, M. Ehle, P. A. Evans, N. Gehrels, M. R. Goad, S. Golenetskii, C. Guidorzi, C. Mundell, M. J. Page, G. Ricker, T. Sakamoto, B. E. Schaefer, M. Stamatikos, E. Troja, M. Ulanov, F. Yuan, H. Ziaeepour

摘要:

雨燕触发了GRB 061121(z=1.314)主爆发的前兆,允许从光学到伽马射线波段进行观测。许多其他望远镜,包括Konus-Wind,XMM-Newton,ROTSE和Faulkes Telescope North,也观察到了爆发。γ射线、X射线和UV/光学发射都在触发后约75秒显示出峰值,尽管光学和X射线余辉分量也在早期出现-在主峰之前或期间。在整个爆发过程中可以看到光谱的演变,快速发射显示出亮度和硬度之间明显的正相关关系。瞬发辐射的光谱能量分布(SED)从1 eV延伸到1 MeV,非常平坦,在~ 1 keV处有一个通量密度峰值。此时的光学-X射线光谱更好地符合一个破碎的,而不是单一的幂律,类似于以前的X射线耀斑结果。随着余辉随时间的变化,SED显示出光谱硬化。这种行为可能是自康普顿化的一种症状,尽管需要类似于分子云核心的星周密度。余辉的衰减速度也太慢,无法用标准模型来解释。虽然前兆和主辐射表现出不同的光谱滞后,但两者都符合长爆发的滞后光度相关。GRB 061121是雨燕探测到的瞬间最亮的长爆发。结合Swift和Konus-Wind的数据,我们估计在GRB静止坐标系中,在1 keV-10 MeV范围内,各向同性能量为2.8 × 10^53尔格。在约2x10^5秒时探测到一个可能的喷流破裂,由此估算出经射束校正的伽马射线能量约为10^51尔格。

英文摘要:

Swift triggered on a precursor to the main burst of GRB 061121 (z=1.314), allowing observations to be made from the optical to gamma-ray bands. Many other telescopes, including Konus-Wind, XMM-Newton, ROTSE and the Faulkes Telescope North, also observed the burst. The gamma-ray, X-ray and UV/optical emission all showed a peak ~75s after the trigger, although the optical and X-ray afterglow components also appear early on - before, or during, the main peak. Spectral evolution was seen throughout the burst, with the prompt emission showing a clear positive correlation between brightness and hardness. The Spectral Energy Distribution (SED) of the prompt emission, stretching from 1eV up to 1MeV, is very flat, with a peak in the flux density at ~1keV. The optical-to-X-ray spectra at this time are better fitted by a broken, rather than single, power-law, similar to previous results for X-ray flares. The SED shows spectral hardening as the afterglow evolves with time. This behaviour might be a symptom of self-Comptonisation, although circumstellar densities similar to those found in the cores of molecular clouds would be required. The afterglow also decays too slowly to be accounted for by the standard models. Although the precursor and main emission show different spectral lags, both are consistent with the lag-luminosity correlation for long bursts. GRB 061121 is the instantaneously brightest long burst yet detected by Swift. Using a combination of Swift and Konus-Wind data, we estimate an isotropic energy of 2.8x10^53 erg over 1keV - 10MeV in the GRB rest frame. A probable jet break is detected at ~2x10^5s, leading to an estimate of ~10^51 erg for the beaming-corrected gamma-ray energy.

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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