English

Seminars

DateSpeakerTitleNote
2017-04-07Zhongli ZhangAn Introduction of GLEAM Survey
Abstract: See http://202.127.29.4/CRATIV/zh-cn/gleam.html
2017-04-14Zhongli Zhang, Xiaopeng ChengAn Introduction of AGN including CSO/CSS/GPS
Abstract: See http://202.127.29.4/CRATIV/zh-cn/gleam.html
2017-04-21Sander FreyHigh-z AGN

Abstract: The extremely high-redshift (z = 5.3) radio source SDSS J102623.61+254259.5 (J1026+2542) is among the most distant and most luminous radio-loud active galactic nuclei (AGN) known to date. Its one-sided radio jet structure on milliarcsecond (mas) and ˜10-mas scales typical for blazars was first imaged at 5 GHz with very long baseline interferometry (VLBI) in 2006. Here we report on our dual-frequency (1.7 and 5 GHz) imaging observations performed with the European VLBI Network (EVN) in 2013. The prominent jet structure allows us to identify individual components whose apparent displacement can be detected over the time span of 7.33 yr. This is the first time when jet proper motions are directly derived in a blazar at z > 5. The small values of up to ˜0.1 mas yr-1 are consistent with what is expected in a relativistic cosmological model if redshift is a measure of distance. The apparent superluminal jet speeds, considered tentative because derived from two epochs only, exceed 10 c for three different components along the jet. Based on modelling its spectral energy distribution, J1026+2542 is known to have its X-ray jet oriented close to the line of sight, with significant Doppler boosting and a large bulk Lorentz factor (Γ ≈ 13). The new VLBI observations, indicating ˜2.3 × 1012 K lower limit to the core brightness temperature, are consistent with this picture. The spectral index in the core region is -0.35.

See http://adsabs.harvard.edu/abs/2015MNRAS.446.2921F

2017-04-28Wei Zhao et alMWA proposal finalising
Abstract: The 2017-B Call For Proposals is now available. Proposals should be submitted through the 2017B proposal form. History observing-awards
2017-05-12Xiaofeng LiData analysis of interferometers-SKA and others
Abstract:
2017-05-19Quan GuoThe faint radio sky
Abstract: http://adsabs.harvard.edu/abs/2016A%26ARv..24...13P
2017-05-26Prashanth Mohan
Abstract:
2017-06-02Xiaopeng ChengSKA era of AGN science in general
Abstract:
2017-06-09Yingkang ZhangSKA science of high-z AGN
Abstract:
2017-06-16Hao DingPulsar science of VLBI and SKA
Abstract:
2017-06-23Wei ZhaoInvestigation of HI/HII sciences
Abstract:
2017-06-30Zhongli ZhangSKA science of X-ray binaries
Abstract:
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