The Peculiar Optical Spectrum of 4C+22.25: Imprint of a Massive Black Hole Binary?

Decarli, R.; Dotti, M.; Montuori, C.; Liimets, T.; Ederoclite, A.
Bibliographical reference

The Astrophysical Journal Letters, Volume 720, Issue 1, pp. L93-L96 (2010).

Advertised on:
9
2010
Number of authors
5
IAC number of authors
1
Citations
31
Refereed citations
28
Description
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.