Astronomers use LAMOST to find over 1,300 new quasars behind Galactic plane

BEIJING, April 18 (Xinhua) -- A group of astronomers has found over 1,300 new quasars behind the Galactic plane by using China's Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), and the scientists said the results shed new light on some hot issues of cosmic research.

Quasars are the remarkably bright cores of active galaxies in the distant universe. Astronomers have been committed to discovering more quasars for the study of cosmic issues such as the large-scale structure of the universe, supermassive black holes, cosmic reionization, and the formation and evolution of galaxies.

Astronomers from China's National Astronomical Observatories, Peking University, University of Chinese Academy of Sciences, Beijing Normal University, and the Netherlands' Leiden University used LAMOST to carry out spectroscopic surveys and identify 1,982 quasars, of which 1,338 are newly discovered, according to the study recently published in the Astrophysical Journal Supplement Series.

The Galactic plane is a region within the Milky Way Galaxy where stars, gas and dust are highly concentrated, forming a huge disk that stretches across the galaxy. Large-scale quasar surveys mainly focus on high Galactic latitude regions in the northern and southern skies and usually do not cover the Galactic plane region.

According to Wu Xuebing, leader of the study and a professor with the Department of Astronomy, School of Physics, Peking University, the high dust extinction and dense star distribution in the Galactic plane make the search for quasars behind the Galactic plane very difficult.

This discovery shows researchers the potential for searching for quasars behind the Galactic plane region based on spectroscopic surveys, he added.

Quasars behind the Galactic plane are excellent tracers to probe the chemistry and kinematics of the interstellar and intergalactic medium in the Milky Way Galaxy, said the paper's first author, Huo Zhiying, at the National Astronomical Observatories.

Moreover, those quasars will fill the gap in the spatial distribution of known quasars near the Galactic plane, and can be used to construct an astrometric reference frame, Huo added.