Discovery of Merging Twin Quasars at z = 6.05

Autor: Yoshiki Matsuoka, Takuma Izumi, Masafusa Onoue, Michael A. Strauss, Kazushi Iwasawa, Nobunari Kashikawa, Masayuki Akiyama, Kentaro Aoki, Junya Arita, Masatoshi Imanishi, Rikako Ishimoto, Toshihiro Kawaguchi, Kotaro Kohno, Chien-Hsiu Lee, Tohru Nagao, John D. Silverman, Yoshiki Toba
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: The Astrophysical Journal Letters, Vol 965, Iss 1, p L4 (2024)
Druh dokumentu: article
ISSN: 2041-8213
2041-8205
DOI: 10.3847/2041-8213/ad35c7
Popis: We report the discovery of two quasars at a redshift of z = 6.05 in the process of merging. They were serendipitously discovered from the deep multiband imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. The quasars, HSC J121503.42−014858.7 (C1) and HSC J121503.55−014859.3 (C2), both have luminous (>10 ^43 erg s ^−1 ) Ly α emission with a clear broad component (full width at half maximum >1000 km s ^−1 ). The rest-frame ultraviolet (UV) absolute magnitudes are M _1450 = − 23.106 ± 0.017 (C1) and −22.662 ± 0.024 (C2). Our crude estimates of the black hole masses provide $\mathrm{log}({M}_{\mathrm{BH}}/{M}_{\odot })=8.1\pm 0.3$ in both sources. The two quasars are separated by 12 kpc in projected proper distance, bridged by a structure in the rest-UV light suggesting that they are undergoing a merger. This pair is one of the most distant merging quasars reported to date, providing crucial insight into galaxy and black hole build-up in the hierarchical structure formation scenario. A companion paper will present the gas and dust properties captured by Atacama Large Millimeter/submillimeter Array observations, which provide additional evidence for and detailed measurements of the merger, and also demonstrate that the two sources are not gravitationally lensed images of a single quasar.
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