On January 10th, 2018 (Beijing time), the eBOSS team, which is an international collaboration running the world’s largest galaxy survey of eBOSS, released the latest science result: a measurement of Redshift Space Distortions (RSD) with a high significance has been successfully performed, using observations of quasars distributed 6.8 to 10.5 billion light years away from us (with redshifts 0.8 to 2.2).This is a first probe of the cosmic structure growth using quasars.

RSD is a special pattern of the three-dimensional distribution of cosmic tracers due to the effect of local gravitational potential. As RSD is essentially caused by gravity, it is one the most important probes of gravity on cosmic scales. Back in 2001, scientists first observed the RSD signal from clustering of galaxies in our local Universe. The RSD measurement from eBOSS is performed using quasars in the deep Universe, when the Universe was only a third to a half size of that today, which is a first attempt in history. This is another significant progress made by the eBOSS team, which has important implications in science frontiers including the study of dark energy and gravity, after the first Baryonic Acoustic Oscillations (BAO) measurement using quasars reported by the same team in May, 2017.

The eBOSS team has released seven science papers, with two of which led by Prof. Gong-Bo Zhao and Dandan Wang (PhD student) at NAOC respectively, and Dr. Yuting Wang (NAOC) are co-leaders of both papers. The papers have been released on arXiv on January 10th, 2018.

Prof. Gong-Bo Zhao has been appointed as a working group co-chair of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey (eBOSS；2014-2020) since 2015, and he has been co-leading the eBOSS team to reduce observational data and perform cosmological implications as scheduled. The progress made so far has confirmed the feasibility for cosmological studies using quasars, which lays the foundation for further cosmic studies using the complete eBOSS sample including the emission line and luminous red galaxies in 2019.