안녕하십니까.

오는 수요일(12월 3일) 오후 4:00에 아래와 같이 2025년 하반기 정규 콜로키움이 진행될 예정입니다.

발표 후에는 연사와의 대화시간(5:00-5:40) 및 저녁 식사가 예정되어 있으니 많은 참여 부탁드립니다.

발표자: 류동수 교수 (UNIST)

호스트: 김상철

장소: 장영실홀 331-2 및 원격 연결

일시: 12월 3일 (수) 오후 4:00

접속주소: https://zoom.us/j/96778730290?pwd=guUS8r1bFbggZKMRVcSiTBnIGnZL8p.1

교육학점: 천문연 소속 현장참석자의 경우 필수 0.5 학점 부여

제목: Ultrahigh-Energy Cosmic Rays Accelerated in FR Radio Galaxy Jets

초록: 

Cosmic rays have been observed as part of multi-messenger astronomy and have provided clues about astronomical objects. Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles known in the Universe, yet their origins remain elusive. Radio galaxies, with their powerful relativistic jets, are widely considered promising UHECR sources. We present a study to investigate particle acceleration within the jets of Fanaroff–Riley (FR) type I and II radio galaxies using numerical simulations. We model the nonlinear dynamics of ultra-relativistic jets with a high-order relativistic hydrodynamics code, and subsequently track cosmic-ray transport and acceleration through a Monte Carlo framework. Our simulations show that the dominant acceleration mechanism is relativistic shear acceleration operating at the interface between the jet spine and the surrounding backflow (cocoon). Additional, though less efficient, contributions arise from shocks and turbulence within the backflow region. Based on these results, we derive model UHECR spectra for FR I and FR II jets, offering a framework for interpreting UHECR observations at Earth, particularly those associated with nearby radio galaxies.

진행언어: 영어

슬라이드언어: 영어

원격 접속 방법 :

A. 웹 브라우저: Chrome을 추천하며 아래 주소를 실행시 Zoom 구동을 위한 프로그램이 설치될 수 있음

B. 접속 주소: https://zoom.us/j/96778730290?pwd=guUS8r1bFbggZKMRVcSiTBnIGnZL8p.1

C. 유의사항: 접속 후 "마이크는 뮤트로 설정" - 기본설정은 뮤트로 되어있음 > 질의 응답시간에는 마이크를 사용해서 질문 가능함

천문연 콜로키움 위원회 (김종수, 선광일, 이창원, 문홍규, 노혜림, 한정열)

운영위원회 (김진호, 김영민, 이석호, 홍준석, 석지연, 이재현)

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Dear all,

The KASI's regular colloquium is scheduled at Dec. 3, as shown below.

A conversation session with speakers and dinner are scheduled after the colloquium.

Speaker: Prof. Dongsu Ryu (UNIST)

Host: 김상철

Place: Jang Yeong-sil Hall 331-2 & Online

Time: December 3 (Wed) 4:00 pm 

Access: https://zoom.us/j/96778730290?pwd=guUS8r1bFbggZKMRVcSiTBnIGnZL8p.1

KASI Educational credits: 0.5 educational credits are awarded to off-line attendees.

Title: Ultrahigh-Energy Cosmic Rays Accelerated in FR Radio Galaxy Jets

Abstract: 

Cosmic rays have been observed as part of multi-messenger astronomy and have provided clues about astronomical objects. Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles known in the Universe, yet their origins remain elusive. Radio galaxies, with their powerful relativistic jets, are widely considered promising UHECR sources. We present a study to investigate particle acceleration within the jets of Fanaroff–Riley (FR) type I and II radio galaxies using numerical simulations. We model the nonlinear dynamics of ultra-relativistic jets with a high-order relativistic hydrodynamics code, and subsequently track cosmic-ray transport and acceleration through a Monte Carlo framework. Our simulations show that the dominant acceleration mechanism is relativistic shear acceleration operating at the interface between the jet spine and the surrounding backflow (cocoon). Additional, though less efficient, contributions arise from shocks and turbulence within the backflow region. Based on these results, we derive model UHECR spectra for FR I and FR II jets, offering a framework for interpreting UHECR observations at Earth, particularly those associated with nearby radio galaxies.

Language: English

Slide Language: English

Remote access procedure:

A. Web browser: Chrome - When executing the address below, a program for additional zoom operation can be installed.

B. Access: Go to  https://zoom.us/j/96778730290?pwd=guUS8r1bFbggZKMRVcSiTBnIGnZL8p.1

C. Notice: After join, Please mute your microphone. - The default setting is microphone mute. > After the presentation, during the Q&A session, you can use the microphone to ask questions.

KASI Colloquium committee (Jongsoo Kim, Kwang-Il Seon, Chang Won Lee, Hong-Kyu Moon, Hyerim Noh, Jeong-Yeol Han)

Working committee (Jinho Kim, Young-Min Kim, Seokho Lee, Junseok Hong,  Ji Yeon Seok, Jaehyun Lee)