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Title: A Candidate Kiloparsec-scale Quasar Pair at z = 5.66
Abstract

We report the discovery of a close quasar pair candidate atz= 5.66, J2037–4537. J2037–4537 is resolved into two quasar images at the same redshift in ground-based observations. Follow-up spectroscopy shows significant differences in both the continuum slopes and emission line properties of the two images. The two quasar images have a projected separation of 1.″24 (7.3 kpc atz= 5.66) and a redshift difference of Δz≲ 0.01. High-resolution images taken by the Hubble Space Telescope do not detect the foreground lensing galaxy. The observational features of J2037–4537 strongly disfavor the lensing hypothesis. If J2037–4537 is a physical quasar pair, it indicates a quasar clustering signal of ∼105at a separation of ∼10 proper kpc (pkpc), and gives the first observational constraint on the pair fraction ofz> 5 quasars,fpair(r< 30 pkpc) > 0.3%. The properties of J2037–4537 are consistent with those of merger-triggered quasar pairs in hydrodynamical simulations of galaxy mergers.

 
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Award ID(s):
1908284
NSF-PAR ID:
10306022
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal Letters
Volume:
921
Issue:
2
ISSN:
2041-8205
Format(s):
Medium: X Size: Article No. L27
Size(s):
["Article No. L27"]
Sponsoring Org:
National Science Foundation
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