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A close quasar pair in a disk-disk galaxy merger at z = 2.17
- Source :
- Nature, 616, 45 (2023)
- Publication Year :
- 2022
-
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 important 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 mergers, no unambiguous dual quasar is known at cosmic noon ($z\approx2$), the peak of global star formation and quasar activity. Here we report multiwavelength observations of 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.<br />Comment: 88 pages, 18 figures, 8 tables; published
Details
- Database :
- arXiv
- Journal :
- Nature, 616, 45 (2023)
- Publication Type :
- Report
- Accession number :
- edsarx.2209.11249
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1038/s41586-023-05766-6