Finding Quasars Behind the Galactic Plane: Spectroscopic Identifications of ~1300 New Quasars at |b|<=20 degree from LAMOST DR10

TL;DR

This study identifies approximately 1300 new quasars behind the Galactic plane using LAMOST DR10 data, enhancing the spatial distribution of known quasars and providing valuable resources for astrophysical research.

Contribution

The paper presents a large sample of spectroscopically confirmed low Galactic latitude quasars, including many newly discovered, from LAMOST DR10, expanding the catalog of GPQs for various scientific applications.

Findings

1982 GPQs confirmed spectroscopically, 1338 are new discoveries.

Most GPQs are located around 240<l<90 degrees with a non-uniform spatial distribution.

Redshift distribution peaks around 1.5, mostly between 0.3 and 2.5.

Abstract

Quasars behind the Galactic plane (GPQs) are excellent tracers to probe the chemistry and kinematics of the interstellar/intergalactic medium (ISM/IGM) of the Milky Way along sight lines via absorption line spectroscopy. Moreover, the quasars located at low Galactic latitudes 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 for accurate measurements of proper motions (PMs) of stars, and substructures of the Milky Way. We started a survey of background quasars in the low Galactic latitude region since the LAMOST phase II survey in 2017. Quasar candidates have been selected from the optical and infrared photometric data of Pan-STARRS1 and WISE surveys based on their variability and color properties. In this paper, we present a sample of 1982 spectroscopically confirmed GPQs with |b| <= 20 degree based on LAMOST Data Release 10 (DR10). Among them, 1338 are newly discovered. Most GPQs are located around 240<l<90 degree, and the spatial distributions are non-uniform. These GPQs have a magnitude distribution with a peak at i-mag 19.0, and mostly around 18.0-19.5mag. The peak of redshift distributions is around ~1.5, and most GPQs have redshifts between 0.3 and 2.5. Our finding demonstrates the potential discovery space for the GPQs from the spectroscopic surveys and the promising applications for future research.