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Galaxies 2016, 4(4), 36;

The Blazar Sequence 2.0

INAF—Osservatorio Astronomico di Brera, Merate I–23807, Italy
Academic Editors: Jose L. Gómez, Alan P. Marscher and Svetlana G. Jorstad
Received: 28 July 2016 / Revised: 20 September 2016 / Accepted: 21 September 2016 / Published: 27 September 2016
(This article belongs to the Special Issue Blazars through Sharp Multi-wavelength Eyes)
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This paper discusses the spectral energy distribution (SED) of all blazars with redshift detected by the Fermi satellite and listed in the 3LAC catalog. The so called “blazar sequence” from the phenomenological point of view will be updated, with no theory or modelling. It will be shown that: (i) pure data show that jet and accretion power are related; (ii) the updated blazar sequence maintains the properties of the old version, albeit with a less pronounced dominance of the γ-ray emission; (iii) at low bolometric luminosities, two different types of objects have the same high energy power: low black hole mass flat spectrum radio quasars and high mass BL Lacs. Therefore, at low luminosities, there is a very large dispersion of SED shapes; (iv) in low power BL Lacs, the contribution of the host galaxy is important. Remarkably, the luminosity distribution of the host galaxies of BL Lacs are spread in a very narrow range; (v) a simple sum of two smoothly joining power laws can describe the blazar SEDs very well. View Full-Text
Keywords: galaxies: active; galaxies: jets; gamma-rays: general; radiation mechanisms: non-thermal; radiation mechanisms: thermal galaxies: active; galaxies: jets; gamma-rays: general; radiation mechanisms: non-thermal; radiation mechanisms: thermal

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Ghisellini, G. The Blazar Sequence 2.0. Galaxies 2016, 4, 36.

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