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arXiv 0806.1182astro-ph
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GRB 060526的光度学和光谱学:z=3.2伽马射线暴余辉和宿主星系的详细研究

Photometry and spectroscopy of GRB 060526: A detailed study of the afterglow and host galaxy of a z=3.2 gamma-ray burst

C. C. Thöne, D. A. Kann, G. Jóhannesson, J. H. Selj, A. O. Jaunsen, J. P. U. Fynbo, C. W. Akerlof, K. S. Baliyan, C. Bartolini, I. F. Bikmaev, J. S. Bloom, R. A… 展开作者

C. C. Thöne, D. A. Kann, G. Jóhannesson, J. H. Selj, A. O. Jaunsen, J. P. U. Fynbo, C. W. Akerlof, K. S. Baliyan, C. Bartolini, I. F. Bikmaev, J. S. Bloom, R. A. Burenin, B. E. Cobb, S. Covino, P. A. Curran, H. Dahle, A. Ferrero, S. Foley, J. French, A. S. Fruchter, S. Ganesh, J. F. Graham, G. Greco, A. Guarnieri, L. Hanlon, J. Hjorth, M. Ibrahimov, G. L. Israel, P. Jakobsson, M. Jelínek, B. L. Jensen, U. G. Jørgensen, I. M. Khamitov, T. S. Koch, A. J. Levan, D. Malesani, N. Masetti, S. Meehan, G. Melady, D. Nanni, J. Näränen, E. Pakstiene, M. N. Pavlinsky, D. A. Perley, A. Piccioni, G. Pizzichini, A. Pozanenko, P. W. A. Roming, W. Rujopakarn, V. Rumyantsev, E. S. Rykoff, D. Sharapov, D. Starr, R. A. Sunyaev, H. Swan, N. R. Tanvir, F. Terra, P. M. Vreeswijk, A. C. Wilson, S. A. Yost, F. Yuan

摘要:

目的:研究$z=3.221$的伽马射线暴(GRB)060526的余辉光变曲线和环境。研究方法:我们提出了一个最大的光度数据集获得的伽玛射线暴余辉,包括从紫外到近红外的多色光度数据。该数据集总共包含412个数据点,我们从文献中添加了额外的数据。此外,我们提出了低分辨率的高信号噪声光谱的余辉。余辉光变曲线建模与分析模型,使用破幂律拟合和宽带数值模型,其中包括能量注入。在光谱中检测到的吸收线被用来获得柱密度使用多离子单组分曲线的增长分析,我们从中获得的金属丰度的主机GRB 060526。结果:余辉的时间行为遵循双破幂律,在$t=0.090\pm0.005$和$t=2.401\pm0.061$天出现破幂。它显示出偏离平滑的幂律集,可以通过从中央引擎注入额外的能量来建模,尽管仍然存在一些显著的微观变化。余辉的宽带光谱能量分布显示沿视线没有明显的消光。由\ion{S}{II}和\ion{Fe}{II}得到的金属丰度[S/H] = --0.57 $\pm$ 0.25和[Fe/H] = --1.09 $\pm$ 0.24对于在该红移的星系来说是相对较高的,但与在类似红移的其他伽玛暴宿主的金属丰度相当。在余辉的位置上,没有发现F775 W(AB)= 28.5等的HST,这意味着宿主M(1500 $>$)的绝对星等为18.3等,比大多数长持续时间的宿主要暗,尽管伽玛暴可能与距离11 kpc的暗星系有关。

英文摘要:

Aims: With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst (GRB) 060526 at $z=3.221$. Methods: We present one of the largest photometric datasets ever obtained for a GRB afterglow, consisting of multi-color photometric data from the ultraviolet to the near infrared. The data set contains 412 data points in total to which we add additional data from the literature. Furthermore, we present low-resolution high signal-to-noise spectra of the afterglow. The afterglow light curve is modeled with both an analytical model using broken power law fits and with a broad-band numerical model which includes energy injections. The absorption lines detected in the spectra are used to derive column densities using a multi-ion single-component curve-of-growth analysis from which we derive the metallicity of the host of GRB 060526. Results: The temporal behaviour of the afterglow follows a double broken power law with breaks at $t=0.090\pm0.005$ and $t=2.401\pm0.061$ days. It shows deviations from the smooth set of power laws that can be modeled by additional energy injections from the central engine, although some significant microvariability remains. The broadband spectral-energy distribution of the afterglow shows no significant extinction along the line of sight. The metallicity derived from \ion{S}{II} and \ion{Fe}{II} of [S/H] = --0.57 $\pm$0.25 and [Fe/H] = --1.09$\pm$0.24 is relatively high for a galaxy at that redshift but comparable to the metallicity of other GRB hosts at similar redshifts. At the position of the afterglow, no host is detected to F775W(AB) = 28.5 mag with the HST, implying an absolute magnitude of the host M(1500 Å)$>$--18.3 mag which is fainter than most long-duration hosts, although the GRB may be associated with a faint galaxy at a distance of 11 kpc.

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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