A redshifted excess in the broad emission lines after the flare of the $\gamma$-ray narrow-line Seyfert 1 PKS 2004-447

W. Hon, M. Berton, E. Sani +6

PKS 2004-447 is a narrow-line Seyfert 1 (NLS1) harbouring a relativistic jet with gamma-ray emission. On 2019-10-25, the Fermi-Large Area Telescope captured a $\gamma$-ray flare from th…