We report the discovery of peculiar features in the optical spectrum of 4C+22.25, a flat spectrum radio quasar at z = 0.4183 observed in the Sloan Digital Sky Survey and in a dedicated spectroscopic follow-up from the Nordic Optical Telescope. The Hβ and Hα lines show broad profiles (FWHM ∼ 12,000 km s-1), faint fluxes, and extreme offsets (Δv = 8700 ± 1300 km s-1) with respect to the narrow emission lines. These features show no significant variation in a time lag of ∼3.1 yr (rest frame).We rule out possible interpretations based on the superposition of two sources or on recoiling black holes, and discuss the virtues and limitations of a massive black hole binary scenario.
Decarli, R., Dotti, M., Montuori, C., Liimets, T., Ederoclite, A. (2010). The Peculiar Optical Spectrum of 4C+22.25: Imprint of a Massive Black Hole Binary?. THE ASTROPHYSICAL JOURNAL LETTERS, 720(1), L93-L96 [10.1088/2041-8205/720/1/L93].
The Peculiar Optical Spectrum of 4C+22.25: Imprint of a Massive Black Hole Binary?
Dotti, M
;
2010
Abstract
We report the discovery of peculiar features in the optical spectrum of 4C+22.25, a flat spectrum radio quasar at z = 0.4183 observed in the Sloan Digital Sky Survey and in a dedicated spectroscopic follow-up from the Nordic Optical Telescope. The Hβ and Hα lines show broad profiles (FWHM ∼ 12,000 km s-1), faint fluxes, and extreme offsets (Δv = 8700 ± 1300 km s-1) with respect to the narrow emission lines. These features show no significant variation in a time lag of ∼3.1 yr (rest frame).We rule out possible interpretations based on the superposition of two sources or on recoiling black holes, and discuss the virtues and limitations of a massive black hole binary scenario.
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