Observations of Gamma-Ray Afterglows with Wide-field Optical Telescope

用宽视场光学望远镜观测伽马射线余辉

• 批准号: 10640241
• 负责人: YOSHIDA Atsumasa
• 金额: $ 1.92万
• 依托单位: RIKEN
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640241/
• 关键词: GRB; aftegalow; optical transient; γ線バースト; アフターグロー; 可視光トランジェント

We bave successfulty obtained wide field images of 5degree times 5degrees using the prototype telescope built for the TONBO projed. However, we coald not detect any optical afterglow from the Gamma-Ray Burst <GRB) due to more than one-year delay of the laanch of tbe HETE-2 satellite which we planned to utilize for GRB Iocations, and umknown instability of the telescope focus plane depending on the temperature.The techniques and knowledge obtained throagh this research, for instance a method of the rapid transfer of GRB ioformation via Internet, cad be utilized in the project of robotic telescope, RIBOTS. Furtbermore, the techniqae developed in this research on detecting unknown transients can be employed in the follow-up obselvations of GRBs at the Kiso Observatony A wide-field-of-view Air Cherenkov telescope nov under development by our group employs the knowledge obtained throagb this research. Some researchers have reported the detection of very bigh energy gamma-rays, over 100 GeV, from GRBs while they were rather statistically poor detections. It is clearty important to confirm such high energy gamma-ray emissions from GRBs. Ordinary Cherenkov tetescopes, however, have only small field-of-view and there needs a new type telescope with large field-of-view.We studied X-ray afterglows of GRBs as well. The most important result we got using the ASCA, lapanese X-ray satetlite, is to detect a emission, line like structure in the spectrum of GRB970828. We show that this structare can be interpreted as a radidative recombination edge from irons around the barst source, wbich is fully consistent with the redshift given by the optical spectroscopy of the afterglow. Tnts iadicates tbe existence of iron-rich environment of GRBS and sports the GRB scenario of massive star collapse.

我们已经成功地使用为TONBO项目建造的原型望远镜获得了5度乘5度的宽视场图像。然而，由于我们计划用于GRB定位的HETE-2卫星的发射延迟了一年多，以及望远镜焦平面随温度的未知不稳定性，我们无法探测到伽玛射线暴（GRB）的任何光学余辉。通过这项研究获得的技术和知识，例如通过互联网快速传输GRB信息的方法，可以用于机器人望远镜RIBOTS项目。此外，本研究开发的探测未知瞬变的技术可以应用于Kiso天文台对grb的后续观测。本课课组正在开发的大视场切伦科夫空中望远镜采用了本研究获得的知识。一些研究人员报告说，从伽马射线爆发中探测到能量极高的伽马射线，超过100 GeV，但从统计上看，它们的探测效果相当差。很明显，确认grb的高能伽玛射线发射是很重要的。然而，普通的切伦科夫望远镜只有很小的视场，需要一种具有大视场的新型望远镜。我们也研究了伽马射线暴的x射线余辉。我们使用日本x射线卫星ASCA得到的最重要的结果，是在GRB970828的光谱中探测到一种发射线状结构。我们发现这种结构可以解释为来自原始源周围铁的辐射复合边缘，这与余辉的光学光谱给出的红移完全一致。这表明GRB中存在富铁环境，并具有大质量恒星坍缩的情景。

项目成果

A.Yoshida et al.: "What did ASCA see in the GRB970828 afterglow?"Astronomy & Astrophysics Supplement. 138. 433-434 (1999)

A.Yoshida 等人：“ASCA 在 GRB970828 余辉中看到了什么？”

Atsumasa Yoshida: "The MAXI Experiment"Proceedings of the 9^<th> Marcel Grossmann Meeting. (印刷中). (2002)

Atsumasa Yoshida：“MAXI 实验”第 9 届 Marcel Grossmann 会议记录（正在出版）。

Ohno, Y., et al: "TOMBO : Tombo Observatory for Microlensing and Bursting Objects"RIKEN Review. Vol.47(in press). (2002)

Ohno, Y. 等人：“TOMBO：微透镜和爆炸物体的 Tombo 天文台”RIKEN 评论。

A.Yoshlda et al.: "A Possible Emission Feature in an X-Ray Afterglow of GRB970828 as a Radiative Recombination Edge"Astrophysical Journal (Letters). 557. L27-L30 (2001)

A.Yoshlda 等人：“GRB970828 作为辐射复合边缘的 X 射线余辉中可能的发射特征”天体物理学杂志（快报）。

Miyasaka, H., Shimizu, H. M., et al.: "Development of a small -scale prototype of Fresnel optics for cosmic ray observation"Proceedings of ICRC 2001. (in press). (2001)

Miyasaka, H.、Shimizu, H. M. 等人：“开发用于宇宙射线观测的菲涅尔光学小型原型”，红十字国际委员会会议记录，2001 年。（出版中）。