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arXiv · 1904.08043

SDSS J153636.22+044127.0 and its analogues: shocked outflows, not active binary black holes

Shaohua Zhang·Hongyan Zhou·Xiheng Shi·Tuo Ji·Peng Jiang·Xiang Pan·Zhenfeng Sheng·Luming Sun·Zhihao Zhong
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Abstract

The binary emission-line system, particularly the binary broad-line emission system, is considered the most effective indicator of the black hole binary. A plausible example of such a system, SDSS J153636.22+044127.0, was reported as the first known object with two hydrogen Balmer broad-line systems, which are interpreted to be the result of broad-line regions around a pair of black holes (Boroson \& Lauer 2009). Here, we show the follow-up optical and near-infrared spectral observations of SDSS J153636.22+044127.0 and its analogues. In these objects, the broad hydrogen Balmer and Paschen, He I and Mg II lines share the same peculiar emission-line profile (including a blue system, a red system and a double-peaked disk-line component); however, the invariance in the large time interval, the absence of the blue system in He I $λ$10830 profile and the abnormally strong emission of the hydrogen Pa$β$ blue system oppose the binary proposal. We suggest that these unique broad lines arise from the AGN emission-line region and the shock-heated outflowing gases rather than a binary system of two active black holes.

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Shaohua Zhang, Hongyan Zhou, Xiheng Shi, Tuo Ji, Peng Jiang, Xiang Pan, Zhenfeng Sheng, Luming Sun, Zhihao Zhong. 2019-04-17. SDSS J153636.22+044127.0 and its analogues: shocked outflows, not active binary black holes. https://doi.org/10.3847/1538-4357%2Fab1aa3

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