Changing-look NLS1 galaxies, their detection with SVOM, and the case of NGC 1566

TL;DR

This paper explores changing-look NLS1 galaxies, focusing on detection prospects with SVOM and the case of NGC 1566, highlighting their significance for understanding supermassive black hole environments.

Contribution

It introduces the study of changing-look NLS1 galaxies, discusses NGC 1566 as a prototype, and examines how future missions like SVOM can enhance their detection and understanding.

Findings

NGC 1566 is a nearby prototype of changing-look NLS1 galaxies.

Changing-look NLS1s can reveal new insights into supermassive black hole environments.

Future missions like SVOM are promising for discovering and studying these systems.

Abstract

We discuss applications of the study of the new and barely explored class of changing-look (CL) narrow-line Seyfert 1 (NLS1) galaxies and comment on their detection with the space mission SVOM (Space Variable Objects Monitor). We highlight the case of NGC 1566, which is outstanding in many respects, for instance as one of the nearest known CL AGN undergoing exceptional outbursts. Its NLS1 nature is discussed, and we take it as a nearby prototype for systems that could be discovered and studied in the near future, including with SVOM. Finally, we briefly examine the broader implications and applications of CL events in NLS1 galaxies and show that such systems, once discovered in larger numbers, will greatly advance our understanding of the physics of the environment of rapidly growing supermassive black holes. This White Paper is part of a sequence of publications which explore aspects of our understanding of (CL) NLS1 galaxy physics with future missions.