A close quasar pair in a disk-disk galaxy merger at z = 2.17

Yu-Ching Chen; Xin Liu; Adi Foord; Yue Shen; Masamune Oguri; Nianyi Chen; Tiziana Di Matteo; Miguel Holgado; Hsiang-Chih Hwang; Nadia Zakamska

doi:10.1038/s41586-023-05766-6

A close quasar pair in a disk-disk galaxy merger at z = 2.17

Nature. 2023 Apr;616(7955):45-49. doi: 10.1038/s41586-023-05766-6. Epub 2023 Apr 5.

Authors

Yu-Ching Chen^{1

2}, Xin Liu^{3

4}, Adi Foord⁵, Yue Shen^{1

2}, Masamune Oguri^{6

7}, Nianyi Chen⁸, Tiziana Di Matteo^{8

9

10}, Miguel Holgado⁸, Hsiang-Chih Hwang¹¹, Nadia Zakamska¹²

Affiliations

¹ Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
² National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
³ Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL, USA. xinliuxl@illinois.edu.
⁴ National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Champaign, IL, USA. xinliuxl@illinois.edu.
⁵ Kavli Institute of Particle Astrophysics and Cosmology, Stanford University, Stanford, CA, USA.
⁶ Center for Frontier Science, Chiba University, Chiba, Japan.
⁷ Department of Physics, Graduate School of Science, Chiba University, Chiba, Japan.
⁸ McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA.
⁹ NSF AI Planning Institute for Physics of the Future, Carnegie Mellon University, Pittsburgh, PA, USA.
¹⁰ OzGrav-Melbourne, Australian Research Council Centre of Excellence for Gravitational Wave Discovery, Melbourne, Victoria, Australia.
¹¹ School of Natural Sciences, Institute for Advanced Study, Princeton, NJ, USA.
¹² Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA.

PMID: 37020007
DOI: 10.1038/s41586-023-05766-6

Abstract

Galaxy mergers produce pairs of supermassive black holes (SMBHs), which may be witnessed as dual quasars if both SMBHs are rapidly accreting. The kiloparsec (kpc)-scale separation represents a physical regime sufficiently close for merger-induced effects to be important¹ yet wide enough to be directly resolvable with the facilities currently available. Whereas many kpc-scale, dual active galactic nuclei-the low-luminosity counterparts of quasars-have been observed in low-redshift mergers², no unambiguous dual quasar is known at cosmic noon (z ≈ 2), the peak of global star formation and quasar activity^3,4. Here we report multiwavelength observations of Sloan Digital Sky Survey (SDSS) J0749 + 2255 as a kpc-scale, dual-quasar system hosted by a galaxy merger at cosmic noon (z = 2.17). We discover extended host galaxies associated with the much brighter compact quasar nuclei (separated by 0.46″ or 3.8 kpc) and low-surface-brightness tidal features as evidence for galactic interactions. Unlike its low-redshift and low-luminosity counterparts, SDSS J0749 + 2255 is hosted by massive compact disk-dominated galaxies. The apparent lack of stellar bulges and the fact that SDSS J0749 + 2255 already follows the local SMBH mass-host stellar mass relation, suggest that at least some SMBHs may have formed before their host stellar bulges. While still at kpc-scale separations where the host-galaxy gravitational potential dominates, the two SMBHs may evolve into a gravitationally bound binary system in around 0.22 Gyr.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Grants and funding

GO2-23099X/NASA/NASA/United States