안녕하십니까.

오는 수요일(3월 13일) 오후 4:00에 아래와 같이 2024년 상반기 정규 콜로키움이 진행될 예정입니다.

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

발표자: 사샤 트리페 교수 (Seoul National University)

호스트: 한정열

장소: 장영실홀 331-2 및 원격 연결

일시: 3월 13일 (수) 오후 4:00

접속주소: https://zoom.us/j/92444602963?pwd=VXJzWE1zd3VkYmZ1SjRMeXRFQy9kQT09

교육학점: 천문연 소속 현장참석자의 경우 필수 0.5 학점 부여

제목: Capella: A Space-only High-frequency Radio VLBI Network Formed by a Constellation of Small Satellites

초록: 

Very long baseline radio interferometry (VLBI) with ground-based observatories is limited by the size of Earth, the geographic distribution of antennas, and the transparency of the atmosphere. In this whitepaper, we present Capella, a tentative design of a space-only VLBI system. Using four small (<500 kg) satellites in two orthogonal polar low-Earth orbit planes, and single-band heterodyne receivers operating at frequencies around 690 GHz, the interferometer is able to achieve angular resolutions of approximately 7 microarcsec. Within a total observing time of three days, a near-complete uv plane coverage can be reached. All key components required for Capella - radio telescope, receiver, sampler, recorder, atomic frequency standard, positioning system, data downlink, and pointing control system - are already available, some of them off-the-shelf; the science payload of each satellite has a mass of about 230 kg and consumes about 550 W of power. The data from the telescopes can be correlated on the ground using dedicated versions of existing Fourier transform (FX) software correlators; in addition to the steps required by VLBI data correlation and calibration in general, dedicated routines will be needed to handle the effects of orbital motion, including relativistic corrections. With the specifications assumed in this whitepaper, Capella will be able to address a range of science cases, including: photon rings around supermassive black holes; the acceleration and collimation zones of plasma jets emitted from the vicinity of supermassive black holes; the chemical composition of accretion flows into active galactic nuclei through observations of molecular absorption lines; mapping supermassive binary black holes; the magnetic activity of stars; and nova eruptions of symbiotic binary stars - and, like any substantially new observing technique, has the potential for unexpected discoveries. 

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/92444602963?pwd=VXJzWE1zd3VkYmZ1SjRMeXRFQy9kQT09

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

2024년 상반기 천문연구원 콜로키움 일정

https://www.kasi.re.kr/kor/publication/post/notice/29938

(위 일정은 연사분의 상황에 따라서 변경될 수 있습니다.)

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

운영위원회 (김진호, 송영범, 오재석, 윤용민, 조영수, 홍경수) 

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Dear all,

The KASI's regular colloquium is scheduled at Mar. 13, as shown below.

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

Speaker: Prof. Sascha Trippe (Seoul National University)

Host: Jeong-Yeol Han

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

Time: March 13 (Wed) 4:00 pm 

Access: https://zoom.us/j/92444602963?pwd=VXJzWE1zd3VkYmZ1SjRMeXRFQy9kQT09

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

Title: Capella: A Space-only High-frequency Radio VLBI Network Formed by a Constellation of Small Satellites

Abstract: 

Very long baseline radio interferometry (VLBI) with ground-based observatories is limited by the size of Earth, the geographic distribution of antennas, and the transparency of the atmosphere. In this whitepaper, we present Capella, a tentative design of a space-only VLBI system. Using four small (<500 kg) satellites in two orthogonal polar low-Earth orbit planes, and single-band heterodyne receivers operating at frequencies around 690 GHz, the interferometer is able to achieve angular resolutions of approximately 7 microarcsec. Within a total observing time of three days, a near-complete uv plane coverage can be reached. All key components required for Capella - radio telescope, receiver, sampler, recorder, atomic frequency standard, positioning system, data downlink, and pointing control system - are already available, some of them off-the-shelf; the science payload of each satellite has a mass of about 230 kg and consumes about 550 W of power. The data from the telescopes can be correlated on the ground using dedicated versions of existing Fourier transform (FX) software correlators; in addition to the steps required by VLBI data correlation and calibration in general, dedicated routines will be needed to handle the effects of orbital motion, including relativistic corrections. With the specifications assumed in this whitepaper, Capella will be able to address a range of science cases, including: photon rings around supermassive black holes; the acceleration and collimation zones of plasma jets emitted from the vicinity of supermassive black holes; the chemical composition of accretion flows into active galactic nuclei through observations of molecular absorption lines; mapping supermassive binary black holes; the magnetic activity of stars; and nova eruptions of symbiotic binary stars - and, like any substantially new observing technique, has the potential for unexpected discoveries. 

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/92444602963?pwd=VXJzWE1zd3VkYmZ1SjRMeXRFQy9kQT09

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.

2024A KASI Colloquium Schedule

https://www.kasi.re.kr/kor/publication/post/notice/29938

(This schedule may vary depending on the speakers' schedule.)

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

Working committee (Jinho Kim, Youngbum Song, Jae Sok Oh, Yongmin Yoon, Youngsoo Jo, Kyeongsoo Hong)