今天是   收藏本站 | 联系我们 | 上海天文台 | English
首页 研究领域 研究团组 科研人员 学术活动 工作机会 内部信息
研究领域
 
每周简讯 更多

Seminar talk

Title: Fast Radio Bursts, GPUs, and the largest telescope in the Southern Hemisphere

Speaker: Dr. Chris Flynn(Swinburne University of Technology Hawthorn, Australia)

Time: TBD

 

Title: The Status of Las Campanas Observatory of Carnegie Institution and the Astronomy in Chile

Time: 3 PM, June 18 (Tuesday)

Speaker: Prof. Leopoldo Infante (Pontifical Catholic University of Chile & Las Campanas observatory of Carnegie Institution)

Location: Middle conference room, 3rd floor

Abstract: Prof. Infante would like to give an informal talk about the status of Las Campanas observatory of Carnegie Institution and the astronomy in Chile. He would also like to discuss the possible future collaborations between China (SHAO) and Chile (PUC and LCO).

 

Title: The purest brown dwarf & properties of low-mass celestial populations

Time: 10:30-11:30, July. 19

 Place: middle conference room

Speaker: 张曾华 (ZengHua Zhang; Observatoire de Paris, PSL fellow)

Abstract:

The formation of sub-stars (often referred to as brown dwarfs) which are not massive enough to support steady nuclear reaction in their hearts were predicted in 1962. A few thousands of brown dwarfs have been discovered in the Galactic disk since 1995. However, very few halo brown dwarf candidates were reported.

I will present the discovery of an L type ultra subdwarf, SDSS J0104+15. Our analysis shows SDSS J0104+15 to be the most metal-poor and highest mass substellar object known to-date. SDSS J0104+15 is joined by another five L type extreme and ultra subdwarfs in a `halo brown dwarf transition zone’ in the Teff–[Fe/H] plane, which represents a narrow mass range in which unsteady nuclear fusion occurs. This halo brown dwarf transition zone forms a `substellar subdwarf gap’ for mid L to early T types.

In this talk, I will also try to clarify the difference between the following celestial populations: cool stars, brown dwarfs, and planets; red dwarfs, and ultracool dwarfs; low-mass stars, very low-mass stars, and substellar objects; dwarfs, subdwarfs, extreme subdwarfs, and ultra subdwarfs.

Paper: http://adsabs.harvard.edu/abs/2017MNRAS.468..261Z

RAS press:

http://www.ras.org.uk/news-and-press/2967-astronomers-identify-purest-most-massive-brown-dwarf 

Group meetings and additional talks

Galactic Dynamics Group Journal Club

Title : Revisiting the Tale of Hercules: How Stars Orbiting the Lagrange Points Visit the Sun

Speaker: Yingying Zhou

Time:9:45 am, July 20th(Thursday)

reference: http://adsabs.harvard.edu/abs/2000AJ....119..800D 

http://adsabs.harvard.edu/abs/2015MNRAS.450.4050W 

http://adsabs.harvard.edu/abs/2017MNRAS.465.1621P 

http://adsabs.harvard.edu/abs/2017ApJ...840L...2P 

Abstract

The Hercules stream is an excess of stars with negative U velocities ( away from the Galactic center, GC)  that also move

slower than the Sun's rotation velocity by V ∼ − 50 km s−1. Dehnen (2000) suggested that these stars reach the solar neighborhood (SNd) on orbits due to the Outer Lindblad resonance (OLR) of a short and fast Galactic bar. However, recent measurements show that the Galactic bar extends to 5.0 ± 0.2 kpc from the Galactic center (Wegg et al. 2015). Motivated by this, Pérez-Villegas et al. (2017) propose a novel explanation for the Hercules stream. Their model matches the 3D density of the red clump giant stars (RCGs) in the bulge and bar as well as stellar kinematics in the inner Galaxy. They find that the model naturally predicts a bimodality in the U–V-velocity distribution for nearby stars which is in good agreement with the Gaia DR1 TGAS, RAVE and LAMOST. In the model, the Hercules stream is made of stars orbiting the Lagrange points of the bar which move outward from the bar’s corotation radius to visit the SNd.

Visitors

Name: Prof. Leopoldo Infante

Affiliation: Pontifical Catholic University of Chile & Las Campanas Observatory of Carnegie Institution for Science

Dates: 17th-20th July

Host: Zhenya Zheng

Office: 1618

 
中心简介
1.jpg
    天体物理研究室是上海天文台从事基础天体物理研究的主要机构,包括12个科研团组。研究室的研究方向涉及黑洞和高能天体物理、星系形成与演化、宇宙大尺度 结构、星团和银河系结构、恒星形成、以及行星天体物理等领域,在黑洞吸积与喷流理论、黑洞和星系的共同演化、银河系结构与动力学、计算天体物理等方向具有一定的国际影响力。研究室现有固定研究人员固定研究人员45名,博士后16名,研究生65名。固定研究人员中包括国家杰出青年基金获得者3人、优秀青年基金获得者2人、科学院“百人计划”入选者9人。
    研究室与国内外的天文研究机构有着密切的合作关系,与中国科技大学联合成立了“中国科学院星系和宇宙学重点实验室”,与厦门大学成立了天体物理联合中心。研究室还参与了多项国际、国内天文项目和观测计划,如LAMOST、HXMT、SDSS-IV、TMT、LSST、FAST等。
©2008-2013 中国科学院上海天文台 版权所有
地址:上海市南丹路80号 邮编:200030 邮件:shao@shao.ac.cn