A model for periodic blazars
We describe a scenario to explain blazar periodicities with time-scales of ∼ few years. The scenario is based on a binary supermassive black hole (SMBH) system in which one of the two SMBHs carries a jet. We discuss the various mechanisms that can cause the jet to precess and produce corkscrew patte...
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| Hauptverfasser: | , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
18 October 2016
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| In: |
Monthly notices of the Royal Astronomical Society
Year: 2017, Jahrgang: 465, Heft: 1, Pages: 161-172 |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stw2684 |
| Online-Zugang: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1093/mnras/stw2684
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| Verfasserangaben: | Emanuele Sobacchi, Mattia C. Sormani and Antonio Stamerra |
| Zusammenfassung: | We describe a scenario to explain blazar periodicities with time-scales of ∼ few years. The scenario is based on a binary supermassive black hole (SMBH) system in which one of the two SMBHs carries a jet. We discuss the various mechanisms that can cause the jet to precess and produce corkscrew patterns through space with a scale of ∼ few pc. It turns out that the dominant mechanism responsible for the precession is simply the imprint of the jet-carrying SMBH orbital speed on the jet. Gravitational deflection and Lense-Thirring precession (due to the gravitational field of the other SMBH) are second-order effects. We complement the scenario with a kinematical jet model which is inspired to the spine-sheath structure observed in M87. One of the main advantages of such a structure is that it allows the peak of the synchrotron emission to scale with frequency according to νF ∝ νξ as the viewing angle is changed, where ξ is not necessarily 3 or 4 as in the case of jets with uniform velocity, but can be ξ ∼ 1. Finally, we apply the model to the source PG1553+113, which has been recently claimed to show a Tobs = (2.18 ± 0.08) yr periodicity. We are able to reproduce the optical and gamma-ray light curves and multiple synchrotron spectra simultaneously. We also give estimates of the source mass and size. |
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| Beschreibung: | Gesehen am 25.10.2017 |
| Beschreibung: | Online Resource |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stw2684 |