A Quasar Pair Sample Compiled from DESI Data Release 1

Abstract Interacting quasar pairs (QPs; either dual or binary) provide crucial insights into galaxy mergers, black hole growth, and large-scale structure formation. The current literature reports fewer than 200 spectroscopically confirmed QPs, highlighting the need for larger samples to enable statistically meaningful investigations. In this paper, we present a sample of 1220 QPs and candidates compiled from the DESI Data Release 1 quasar sample. Among them, 145 systems have been previously reported. We visually classified the full sample using DESI Legacy Survey Images and SPARCL spectra into three categories: QPs ( N = 1020), QP candidates ( N = 142), and lensed quasar candidates (LQCs; N = 58). Within the LQC subset, we find an intriguing wide-separation (∼7 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 15) quadruply LQC. The redshift distribution of the pair sample peaks at z ∼ 1–2.5, with an overall pair fraction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.2</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:mn>1</mml:mn> <mml:msup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:math> (Poisson error) and a generally weak redshift dependence. 63.8% of QPs have ∣Δ V r ∣ &lt; 600 km s −1 , suggesting dynamical associations. This sample offers a statistically meaningful dataset for future studies of QPs, lensing events, and potentially merger-triggered or merger-induced supermassive black hole growth across the merger sequence.