안녕하십니까.

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

발표자: 박창범 교수 (고등과학원)

호스트: 노혜림

장소: 장영실홀 331-2 및 원격 연결

일시: 4월 3일 (수) 오후 4:00

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

교육학점: 천문연 소속 현장참석자의 경우 필수 0.5 학점 부여

제목: Discordance of the flat ΛCDM ‘concordance’ model: Evidence for the Dark Energy Equation of State Parameter w > −1

초록: 

The dark energy equation of state parameter w is measured with sufficient accuracy to discover that w must be larger than one in the flat CDM universes, namely dark energy is not the cosmological constant. A series of large-volume galaxy redshift surveys samples up to redshift ~0.8 produced by the Sloan Digital Sky Survey are used in the analysis, and the expansion history of the universe was measured using an extended version of the Alcock-Paczyński test (Park et al. 2019). The test exploits the fundamental fact that gravity is an isotropic force and the statistical pattern of galaxy clustering can be used as a standard shape that is conserved with time.
The new analysis of the SDSS data indicates that the expansion of the universe is indeed accelerating but the acceleration is a little slower than expected in the flat LCDM universe. The dark energy equation of state parameter is measured to be w = −0.903±0.023, a 4.2σ deviation from −1! This finding of a new "w tension" inevitably leads us to discard the cosmological constant as the source for the accelerated expansion and consider alternative quintessence models. We are now making a more accurate measurement of w using the upcoming DESI survey data to test if w is constant or evolving.

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 Apr. 3, as shown below.

Speaker: Prof. Changbom Park (Korea Institute for Advanced Study)

Host: Hyerim Noh

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

Time: April 3 (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: Discordance of the flat ΛCDM ‘concordance’ model: Evidence for the Dark Energy Equation of State Parameter w > −1

Abstract: 

The dark energy equation of state parameter w is measured with sufficient accuracy to discover that w must be larger than one in the flat CDM universes, namely dark energy is not the cosmological constant. A series of large-volume galaxy redshift surveys samples up to redshift ~0.8 produced by the Sloan Digital Sky Survey are used in the analysis, and the expansion history of the universe was measured using an extended version of the Alcock-Paczyński test (Park et al. 2019). The test exploits the fundamental fact that gravity is an isotropic force and the statistical pattern of galaxy clustering can be used as a standard shape that is conserved with time.
The new analysis of the SDSS data indicates that the expansion of the universe is indeed accelerating but the acceleration is a little slower than expected in the flat LCDM universe. The dark energy equation of state parameter is measured to be w = −0.903±0.023, a 4.2σ deviation from −1! This finding of a new "w tension" inevitably leads us to discard the cosmological constant as the source for the accelerated expansion and consider alternative quintessence models. We are now making a more accurate measurement of w using the upcoming DESI survey data to test if w is constant or evolving.

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)