To be or not to be a blazar. The case of the Narrow-Line Seyfert 1 SBS 0846+513

TL;DR

This paper presents evidence that the Narrow-Line Seyfert 1 galaxy SBS 0846+513 hosts a powerful relativistic jet, exhibiting blazar-like behavior, which challenges traditional classifications of active galactic nuclei.

Contribution

It provides multi-wavelength observational evidence that SBS 0846+513 is a young blazar with a relativistic jet, expanding the understanding of jet formation in lower-mass black hole systems.

Findings

Detection of a strong gamma-ray flare in 2011 with luminosity comparable to bright quasars.

VLBA imaging revealed superluminal jet motion indicating high relativistic speeds.

Radio and gamma-ray variability suggest blazar-like behavior in SBS 0846+513.

Abstract

The presence of a relativistic jet in some radio-loud Narrow-Line Seyfert 1s (NLSy1) galaxies, first suggested by their variable radio emission and the flat radio spectra, is now confirmed by the Fermi-LAT detection of five NLSy1s in gamma rays. In particular, a strong gamma-ray flare from SBS 0846+513 was observed in 2011 June by Fermi-LAT reaching a gamma-ray luminosity (0.1-300 GeV) of about 10^48 erg/s, comparable to that of bright flat spectrum radio quasars. Apparent superluminal velocity in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indicators of the presence of a relativistic jet as powerful as those in blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate a blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.