D'Ammando, Filippo

Relativistic jets in Narrow-Line Seyfert 1 galaxies. New discoveries and open questions.

Author list: F. D'Ammando, M. Orienti, J. Finke, J. Larsson, M. Giroletti on behalf of the Fermi LAT Collaboration

Before the launch of the Fermi satellite only two classes of AGNs were known to generate relativistic jets and thus emit up to the gamma-ray energy range: blazars and radio galaxies, both hosted in giant elliptical galaxies. The first two years of observations by the Large Area Telescope on board Fermi confirmed that these two are the most numerous classes of identified sources in the extragalactic gamma-ray sky, but the discovery of gamma-ray emission from 5 radio-loud Narrow-Line Seyfert 1 galaxies revealed the presence of a possible emerging third class of AGNs with relativistic jets. A core-jet structure with apparent superluminal motion of the jet components has been observed in radio for some of them. Considering that Narrow-Line Seyfert 1 are typically hosted in spiral galaxy, this finding poses intriguing questions about the nature of these objects, the onset of production of relativistic jets, and the cosmological evolution of radio-loud AGN.

Here, we discuss the radio-to-gamma-rays properties of the gamma-ray emitting Narrow-Line Seyfert 1 galaxies in the context of the blazar scenario and the unification of relativistic jets at different scales, in particular focusing on PKS 1502+036 and the two flaring sources SBS 0846+513 and PMN J0948+0022.