| 摘要: | 透過台灣的資源（ALMA, SMA, CFHT 和鹿林一米望遠鏡）加上國際合作（Swift, Fermi, Suzaku, Subaru, Pan-STARRS1, JCMT, 和東亞伽瑪射線爆聯測網），我們極力研究伽瑪射線爆高能性質 及低波段的餘暉演化，期望以觀測證據證實伽瑪設線爆的噴流理論。伽瑪射線爆是宇宙強力高 能爆發源之一，除了產生高能爆發外，伽瑪射線爆還會在低能量波段（可見光，無線電波）產 生持續數十天的餘暉輻射。藉由研究這些高能且明亮的爆發，天文學者得以分析不同紅位移的 伽瑪射線爆餘輝以及其宿主星系的特性，使得伽瑪射線爆成為探索遙遠宇宙的重要工具之一。 既有的觀測對伽瑪射線爆的來源所知有限，其餘暉性質也尚未有結論性的歸納，甚至有些觀測 結果無法用現階段的理論模型解釋，因此深入探討伽瑪射線爆的爆發以及輻射機制，為目前天 文學者致力於解析伽瑪射線爆的重要課題。我們已使用ALMA，ＳＭＡ以及可見光望遠鏡的伽 瑪射線爆觀測資料及其餘暉的詳細研究。2014 年3 月上線的（HSC)，將使用5 年300 天的觀 測時間的巡天觀測，其觀測資料得以用來研究上述的課題。我們將集中於以下科學目標：(1) 從 可見光與次毫米波觀測以驗證伽瑪射線爆餘輝的主要機制為同步輻射; (2) 使用HSC 觀測資料 發現伽瑪射線爆孤兒餘輝，並透過次毫米波觀測証實伽瑪射線爆來自噴流機制。 ;Based on our science developments on Gamma Ray Bursts (GRBs) using Taiwanese resources (ALMA, SMA, CFHT, and Lulin Telescopes) and international instruments (Swift, Fermi, Suzaku, SUBARU, Pan-STARRS1, JCMT, and EAFON), we are implementing; (A) new insight on GRBs with submm follow-ups (B) providing of the first evidence of jet collimation of GRBs. GRBs are among the most powerful explosions in the Universe. Their afterglow,which shines in various frequencies (X-ray to radio) are also luminous, and observation is possible at the re-ionization epoch (z~8) using medium-aperture OIR telescopes. These afterglow observations have been providing evidences that some GRBs are produced when stars much more massive than the Sun run out of nuclear fuel and explode. Some GRBs are likely due to gigantic magnetic flares near the surface of exotic dead stars named neutron stars. In addition, the finding of the high-redshift GRB (z=8.1) established the potential for GRBs to probes of the processes and environments of star formation from the earliest cosmic epochs. GRBs are unique and powerful tools that may assist in the study of the early Universe. Therefore, understanding the diversity of the astrophysical entities that form GRBs is an ongoing study that represents one of the most pressing inquiries in modern astrophysics. Here, we focus on (1) their energetics by understanding of the radiation mechanism and (2) jet collimation by observing on-axis and off-axis afterglows. These two topics are fully related each other both scientifically and technically. Because jet collimation is crucial to reduce total radiated energy and to understand entire radiation processes of GRBs with ultra-relativistic outflow (both prompt and afterglow phases). While understanding of radiation process is necessary to predict characterization of off-axis orphan GRB afterglow. However, intensive observations for on-axis GRB afterglows are causing a reappraisal and expansion of the previous standard view of GRBs and the fireball model. To overcome this situation, the characterizations of broadband afterglow spectrum are essential. To realize this observation, we will continue to perform broadband afterglow follow-ups including submm bands based on our successful monitoring programs by using EAFON, SMA, JCMT, and ALMA. For the jet collimation of GRBs, we aim to discover orphan afterglow of GRBs by a strategic optical imaging survey with SUBARU/HSC and radio follow-ups using ALMA. Since the 5 years of strategic surveys (300 nights) were started in March 2014 and ALMA is becoming the full scientific operation mode, the orphan afterglow search is one of the timely and deserved science topics. |
