Gamma-ray Emitting Narrow-Line Seyfert 1 Galaxies: Past, Present, and Future

TL;DR

This review discusses gamma-ray emitting narrow-line Seyfert 1 galaxies, highlighting their significance as young blazar-like objects with relativistic jets, and emphasizes their importance for understanding AGN evolution and jet formation.

Contribution

It synthesizes current knowledge on gamma-ray NLSy1 galaxies, emphasizing their role as young blazars and their potential to reveal jet launching mechanisms in different galactic environments.

Findings

Gamma-ray NLSy1 galaxies have relativistic jets similar to blazars.

They are considered as young, evolving blazar-like AGN.

Multi-wavelength observations support their significance in AGN studies.

Abstract

This article reviews our current understanding about $\gamma$-ray detected narrow-line Seyfert 1 ($\gamma$-NLSy1) galaxies. The detection with the Large Area Telescope onboard {\it Fermi}~Gamma-ray Space Telescope has provided the strongest evidence for the presence of closely aligned relativistic jet in these intriguing active galactic nuclei (AGN) and opened up a realm to explore the physical conditions needed to launch the jet in a different central engine and host galaxy environment than that is known for blazars. Promising results acquired from various multi-wavelength campaigns are converging to a scenario in which the $\gamma$-NLSy1 galaxies can be considered as `young' blazars. These enigmatic sources hold the key to unravel the jet triggering mechanism and evolution of the AGN phase of a galaxy, in general. As such, $\gamma$-NLSy1s should be considered as one of the top priority targets for next generation observational facilities.