안녕하십니까.

이번주 수요일(10월 11일) 오후 4:00에 아래와 같이 정규 콜로키움이 진행될 예정입니다.

이번학기 콜로키움은 수요일 오후 4시에 진행되며, 발표 후에는 연사와의 대화시간 (5:00-5:40) 및 저녁 식사가 예정되어 있으니 많은 참여 부탁드립니다.

발표자 : 류태호 박사 (The Max Planck Institute for Astrophysics)

호스트: 선광일 (광학천문본부)

장소 : 장영실홀 331-2 및 원격 연결

일시 : 10월 11일 (수) 오후 4:00

접속주소 : https://zoom.us/j/91080311762?pwd=QWlCbkRNMnFONkloV28wc2xtb1EwQT09

교육학점: 천문연 소속 현장참석자의 경우 필수 0.5 학점 부여

제목: 

Two types of nuclear transients - tidal disruption events and disruptive collisions

초록: 

Galactic nuclei are extreme environments where stars are densely packed around a supermassive black hole (SMBH). Occasionally, dynamical interactions in the galactic center lead the stars to interact violently at short distances with each other or with the SMBH, resulting in the formation of nuclear transients. In this talk, I will discuss two types of nuclear transients, tidal disruption events and high-velocity collisions between stars, based on the results of detailed hydrodynamics simulations. Tidal disruption events are one of the most dramatic nuclear transients in which a star is tidally disrupted by the SMBH in a few hours. The conventional picture has been that a star is fully disrupted at the first pericenter passage and the debris circularizes rapidly. However, these events are in fact more diverse and they can be categorized into several groups with different observational signatures depending on stellar pericenter distance, from partial disruptions (i.e., partial mass loss and surviving remnant) to full disruptions which is further sub-categorized depending on relativistic effects. On the other hand, disruptive collisions are the events where two stars collide at a very high relative velocity near the central SMBH. The collision product, a homologously expanding gas cloud, can generate a flare as bright as tidal disruption events. Subsequently, the expanding gas cloud would interact with the nearby SMBH, generating a second, possibly even brighter accretion-driven flare. Because these can happen near BHs at any mass scale, if the accretion is efficient, these disruptive collisions could contribute to the growth of black holes.

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/91080311762?pwd=QWlCbkRNMnFONkloV28wc2xtb1EwQT09
C. 유의사항 : 접속 후 "마이크는 뮤트로 설정" - 기본설정은 뮤트로 되어있음
    > 질의 응답시간에는 마이크를 사용해서 질문 가능함

2023년 하반기 KASI 콜로키움 일정

https://www.kasi.re.kr/kor/academy/post/colloquium

(위 일정은 연사분의 상황에 따라서 변경될 수 있습니다.)

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

운영위원회(김진호, 홍성욱, 최지훈, 오희영, 조영수, 홍경수)

Dear all,

The KASI's regular colloquium is scheduled for October 11.

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

Speaker: Dr. Taeho Ryu (The Max Planck Institute for Astrophysics)

Host: Kwang-il Seon

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

Time : October 11 (Wed) 4:00 pm 

Access: https://zoom.us/j/91080311762?pwd=QWlCbkRNMnFONkloV28wc2xtb1EwQT09

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

Title: Two types of nuclear transients - tidal disruption events and disruptive collisions

Abstract: 

Galactic nuclei are extreme environments where stars are densely packed around a supermassive black hole (SMBH). Occasionally, dynamical interactions in the galactic center lead the stars to interact violently at short distances with each other or with the SMBH, resulting in the formation of nuclear transients. In this talk, I will discuss two types of nuclear transients, tidal disruption events and high-velocity collisions between stars, based on the results of detailed hydrodynamics simulations. Tidal disruption events are one of the most dramatic nuclear transients in which a star is tidally disrupted by the SMBH in a few hours. The conventional picture has been that a star is fully disrupted at the first pericenter passage and the debris circularizes rapidly. However, these events are in fact more diverse and they can be categorized into several groups with different observational signatures depending on stellar pericenter distance, from partial disruptions (i.e., partial mass loss and surviving remnant) to full disruptions which is further sub-categorized depending on relativistic effects. On the other hand, disruptive collisions are the events where two stars collide at a very high relative velocity near the central SMBH. The collision product, a homologously expanding gas cloud, can generate a flare as bright as tidal disruption events. Subsequently, the expanding gas cloud would interact with the nearby SMBH, generating a second, possibly even brighter accretion-driven flare. Because these can happen near BHs at any mass scale, if the accretion is efficient, these disruptive collisions could contribute to the growth of black holes.

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/91080311762?pwd=QWlCbkRNMnFONkloV28wc2xtb1EwQT09

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.

2023B KASI Colloquium Schedule

https://www.kasi.re.kr/kor/post/eng_colloquium

(This schedule may be changed according to the situation of the speaker.)

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

Working committee (Jinho Kim, Sungwook E. Hong, Jihoon Choi, Heeyoung Oh, Youngsoo Jo, Kyeongsoo Hong)