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arXiv 1003.3885astro-ph.HE
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四个费米/LAT伽玛暴的光学和近红外后续观测:红移、余辉、能量学和宿主星系

Optical and near-infrared follow-up observations of four Fermi/LAT GRBs : Redshifts, afterglows, energetics and host galaxies

S. McBreen, T. Krühler, A. Rau, J. Greiner, D. A. Kann, S. Savaglio, P. Afonso, C. Clemens, R. Filgas, S. Klose, A. Küpüc Yoldas, F. Olivares E., A. Rossi, G. P… 展开作者

S. McBreen, T. Krühler, A. Rau, J. Greiner, D. A. Kann, S. Savaglio, P. Afonso, C. Clemens, R. Filgas, S. Klose, A. Küpüc Yoldas, F. Olivares E., A. Rossi, G. P. Szokoly, A. Updike, A. Yoldas

摘要:

费米能在很大的能量范围内测量伽马射线暴的光谱特性,并为这些高能事件的瞬时发射打开了一扇新的窗口。费米仪器的定位与斯威夫特的后续行动相结合,为较长波长的观测提供了准确的位置,从而确定了红移、真正的能量收支、宿主星系的性质,并便于与前费米爆发进行比较。对Fermi/LAT探测到的GRB 090323、GRB 090328、GRB 090510和GRB 090902 B四个高能爆发的余辉进行了多波长跟踪观测。它们是用安装在MPG/ESO 2.2米望远镜上的GROND在光学/近红外波段获得的,另外还用德国陶腾堡的2米望远镜在光学波段获得了GRB 090323。其中三个事件被归类为长暴,而GRB 090510是一个很好的本地化短伽玛暴与GeV的排放。此外,在四次爆发中有三次发现了宿主星系。使用GRB 090328和GRB 090510的VLT启动光谱跟踪。给出了所有爆发的7个波段的余辉观测结果,并对它们的宿主星系进行了研究。知识的距离和当地的尘埃消光,使比较的余辉的LAT检测到的伽玛暴与一般的样品。GRB 090328和GRB 090510的光谱红移分别为z=0.7354+/-0.0003和z=0.903 +/-0.001,并分别推导出其宿主星系的尘埃校正恒星形成速率为4.8 M_dot yr^-1和0.60 M_dot yr^-1。长爆发的余辉表现出幂律衰减指数α从小于1到~2.3,光谱指数(β)值从0.65到~1.2,这是相当标准的伽玛射线暴余辉。对小于2.1度至大于6.4度的喷流半开度角施加约束,这允许对射束校正能量施加限制。这些范围从小于5x10^50 erg到有史以来最高的值之一,GRB 090902 B大于2.2x10^52 erg,并且与标准蜡烛不一致。极高能量的长费米爆发的光学余辉位于斯威夫特时代检测到的所有光学余辉的亮度分布的上半部分,如果考虑不完整性,甚至在前5%。这些LAT检测到的爆发的宿主星系在灭绝,恒星形成率和质量方面的属性似乎与以前的样本没有区别。

英文摘要:

Fermi can measure the spectral properties of gamma-ray bursts over a very large energy range and is opening a new window on the prompt emission of these energetic events. Localizations by the instruments on Fermi in combination with follow-up by Swift provide accurate positions for observations at longer wavelengths leading to the determination of redshifts, the true energy budget, host galaxy properties and facilitate comparison with pre-Fermi bursts. Multi-wavelength follow-up observations were performed on the afterglows of four bursts with high energy emission detected by Fermi/LAT : GRB090323, GRB090328, GRB090510 and GRB090902B. They were obtained in the optical/near-infrared bands with GROND mounted at the MPG/ESO 2.2m telescope and additionally of GRB090323 in the optical with the 2 m telescope in Tautenburg, Germany. Three of the events are classified as long bursts while GRB090510 is a well localized short GRB with GeV emission. In addition, host galaxies were detected for three of the four bursts. Spectroscopic follow-up was initiated with the VLT for GRB090328 and GRB090510. The afterglow observations in 7 bands are presented for all bursts and their host galaxies are investigated. Knowledge of the distance and the local dust extinction enables comparison of the afterglows of LAT-detected GRBs with the general sample. The spectroscopic redshifts of GRB090328 and GRB090510 were determined to be z=0.7354+/-0.0003 and z=0.903 +/- 0.001 and dust corrected star-formation rates of 4.8 Mdot yr^-1 and 0.60 M_dot yr^-1 were derived for their host galaxies, respectively. The afterglows of long bursts exhibit power-law decay indices alpha from less than 1 to ~2.3 and spectral indices (beta) values from 0.65 to ~1.2 which are fairly standard for GRB afterglows. Constraints are placed on the jet half opening angles of less than 2.1 deg to greater than 6.4 deg which allows limits to be placed on the beaming corrected energies. These range from less than 5x10^50 erg to the one of the highest values ever recorded, greater than 2.2x10^52 erg for GRB090902B, and are not consistent with a standard candle. The extremely energetic long Fermi bursts have optical afterglows which lie in the top half of the brightness distribution of all optical afterglows detected in the Swift era or even in the top 5% if incompleteness is considered. The properties of the host galaxies of these LAT detected bursts in terms of extinction, star formation rates and masses do not appear to differ from previous samples.

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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