False color image of a 2 square degree region of the LAGER survey field. The small white boxes indicate the positions of the 23 LAEs discovered in the survey. The detailed insets (yellow) show two of the brightest LAEs; (Image by ZHENG Zhenya (SHAO) & WANG Junxian (USTC)).
The first research paper of LAGER is going to open a new world. Over the past decade, the international progress of searching the galaxies at a redshift of z~7 and further Lyman alpha has moved very slowly because of the difficulties in observations and research of 800 million years Universe is the most frontier of the reionization. LAGER has discovered 23 candidate LAEs in the first survey field (4 in total) that was present 800 million years after the Big Bang, the largest sample detected to date at that epoch. Detecting the sample, it found that the amount of Lyman alpha at 1billion year ago was about four times of the amount at earlier 800 million years. The results imply that the process of ionizing the Universe began early and was still incomplete at 800 million years, with the intergalactic gas about half neutral and half ionized at that epoch. The low incidence rate of LAEs at 800 million years resulted from the suppression of their Lyman alpha emission by neutral intergalactic gas, which means the mist began to dissipate at less than 6% Universe age and the first galaxies which accounted for a large proportion of early Universe need to form before 800 million years ago.
Researchers in CITO Astronomical Observatory are installing a specially built narrowband filter NB964(Covered by Chinese Top-notch Young Talents Program) for the superb large-area DEC (Image by National Optical Astronomy Observatory)
The study is published as “First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7,” in the Astrophysical Journal Letters.The organizer of LAGER is WANG Junxian and the first author is ZHENG ZhenYa(Shanghai Astronomical Observatory, University of Science and Technology of China graduate 2012) who is also the co-organizer of LAGER. Other core members are Sangeeta Malhotra (Goddard Space Flight Center and Arizona State University), James Rhoads and Leopoldo Infante (Pontificia Catolica University of Chile and the Carnegie Institution for Science). KONG Xu(University of Science and Technology of China) and WU Weida(University of Science and Technology of China) are co authors. The research is supported by National Science Foundation of China, Chinese Top-notch Young Talents Program, National Basic Research Program of China, the China-Chile Joint Research Fund and the CAS Pioneer Hundred Talents Program (C).
The link of the paper: http://iopscience.iop.org/article/10.3847/2041-8213/aa794f
Prof. WANG Junxian
(Written by LV Jinghao, USTC News Center, School of Physical Sciences)
On May 11, the Nature Publishing Group released Nature Publishing Index 2010 China, remarking “a dramatic rise in the quality of research being published by China”. University of Science and Technology of China is ranked 3rd of TOP 10 Institutions in Index 2010 China.
This article came from News Center of USTC.