Validity of the Blazar-Sequence Luminosity–Peak-Energy Correlation

Establish whether the correlation predicted by the blazar sequence between blazar luminosity and the peak energy of the high-energy spectral component is valid, particularly for the luminous blazar populations observable in the MeV band.

Background

The paper discusses the blazar sequence, which predicts an anti-correlation between bolometric gamma-ray luminosity and the energy of the high-energy spectral peak. This relationship motivates the expectation that the most luminous blazars, especially FSRQs, should peak in the MeV band and therefore be promising targets for future MeV gamma-ray missions.

The authors state that the correlation has not yet been established observationally. Their averaged SEDs do not show the predicted relationship within the FSRQ and BL Lac populations, although the cross-matched sample is subject to selection effects because it is based on sources detected by Swift-BAT and Fermi-LAT. Higher-redshift and more complete MeV observations are therefore needed to determine whether the proposed blazar-sequence relation reflects an intrinsic physical trend.

References

As we discussed in Section \ref{sec:template_SEDS}, this correlation has yet to be proven, and our averaged SED construction demonstrated a lack of relationship.

— Detection Forecasting for Blazars at MeV Energies with Fermi-LAT Swift-BAT Cross Match  (2610.26658 - Wessling-Resnick et al., 19 Oct 2026) in Section 6, High Redshift Detection Forecasting, paragraph beginning “Presently, the highest known redshift blazar”