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The blazar sequence: validity and predictions

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Abstract

The “blazar sequence” posits that the most powerful BL Lacertae objects and flat-spectrum radio quasars should have relatively small synchrotron peak frequencies, ν peak, and that the least powerful such objects should have the highest ν peak values. This would have strong implications for our understanding of jet formation and physics and the possible detection of powerful, moderately high-redshift TeV blazars. I review the validity of the blazar sequence by using the results of very recent surveys and compare its detailed predictions against observational data. I find that the blazar sequence in its simplest form is ruled out. However, powerful flat-spectrum radio quasars appear not to reach the ν peak typical of BL Lacs. This could indeed be related to some sort of sequence, although it cannot be excluded that it is instead due to a selection effect.

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  1. European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching, Germany

    Paolo Padovani

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  1. Paolo Padovani
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Correspondence to Paolo Padovani.

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Padovani, P. The blazar sequence: validity and predictions. Astrophys Space Sci 309, 63–71 (2007). https://doi.org/10.1007/s10509-007-9455-2

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  • DOI: https://doi.org/10.1007/s10509-007-9455-2

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