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

D.W Xu , S Komossa , D Grupe , J Wang , L.P Xin , X.H Han , J.Y Wei , J.Y Bai , E Bon , F Cangemi (1, 2) , B Cordier (3) , M Dennefeld (4) , L.C Gallo , W Kollatschny , De-Feng Kong , M.W Ochmann , Y.L Qiu , N Schartel

1 LPNHE (UMR_7585) - Laboratoire de Physique Nucléaire et de Hautes Énergies
2 APC (UMR_7164) - AstroParticule et Cosmologie
3 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
4 IAP - Institut d'Astrophysique de Paris

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.

Mots clés: active galactic nuclei; Seyfert galaxies; NGC 1566; broad-line region; supermassive black holes; space mission SVOM; accretion disks; optical spectra; X-ray spectra

Domaines: Astrophysique [astro-ph]

D.W Xu, S Komossa, D Grupe, J Wang, L.P Xin, et al.. Changing-look NLS1 galaxies, their detection with SVOM, and the case of NGC 1566. Universe, 2024, 10 (2), pp.61. ⟨10.3390/universe10020061⟩. ⟨hal-04430830⟩