报告题目：A new insight into the origin of repeating FRB 

　　报 告人： Vishal Gajjar, University of California, Berkeley 

　　摘要: 

　　Fast Radio Bursts (FRBs) are some of the most energetic and enigmatic events in the Universe. The origin of these sources is among the most challenging questions of modern-day astrophysics. Among the known FRBs, FRB121102 is the only source known to show repeated bursts which can allow a detailed investigation of various origin models. In August 2017, we initiated a campaign to observe FRB 121102 using the Breakthrough Listen Digital Backend with the C-band receiver at the Robert C. Byrd Green Bank Telescope (GBT).   

　　We also applied state of the art machine learning approach with the Convolution Neural Network (CNN) and found a total of 92 new bursts.  

　　These observations are the highest frequency and widest bandwidth detection of bursts from FRB 121102 (or any other FRB) obtained to-date.  

　　We note that individual bursts show marked changes in spectral extent ranging from hundreds of MHz to several GHz. We also found distinctive temporal structures, a few micro-seconds wide in two of the strongest bursts, suggesting a very compact emission region. The most intriguing findings from these detections are a very high degree of rotation measures (~ 10^5 rad m-2) and nearly 100% linearly polarized bursts.  

　　I will discuss how these detections of FRB 121102 at higher frequencies point towards the origin of FRB 121102 from a compact object embedded in a highly magneto-ionic environment. 

　　报告人简介：  

　　Vishal is a Templeton post-doctoral research fellow at the Berkeley SETI research center. In 2015, he received his Ph.D. from the National Center for Radio Astrophysics in Pune, India. His Ph.D. was on understanding pulsar emission physics by studying various single pulse phenomena. He spends most of his time at UC Berkeley on doing commensal observations with the two of the biggest telescopes. One of the projects he is working on now is on characterizing terrestrial interferences to eliminate false positives in finding ET. He also works on developing a GPU-accelerated broadband periodic emission search pipelines for the Breakthrough Listen. He is part of the team who is designing an experiment to measure giant pulses from the Crab pulsar using a small dish and is also helping FAST telescope to design a real-time FRB detection backend. 

　　报告时间：2018年11月22日（周四）上午11：00 

　　报告地点：台本部南楼210会议室