Interactions among intermediate redshift galaxies

The case of SDSS J134420.86+663717.8^⋆

¹ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50939 Köln, Germany
e-mail: misquitta@ph1.uni-koeln.de
² Max-Planck Institut für Radioastronomie (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany
³ Regional Computer Center (RRZK), Universität zu Köln, Weyertal 121, 50931 Köln, Germany

Received: 28 October 2019
Accepted: 9 May 2020

Abstract

We present the properties of the central supermassive black holes and the host galaxies of the interacting object SDSS J134420.86+663717.8. We obtained optical long slit spectroscopy data from the Large Binocular Telescope using the Multi Object Double Spectrograph. Analysing the spectra revealed several strong broad and narrow emission lines of ionised gas in the nuclear region of one galaxy, whereas only narrow emission lines were visible for the second galaxy. The optical spectra were used to plot diagnostic diagrams, deduce rotation curves of the two galaxies, and calculate the masses of the central supermassive black holes. We find that the galaxy with broad emission line features has Seyfert 1 properties, while the galaxy with only narrow emission line features seems to be star-forming in nature. Furthermore, we find that the masses of the central supermassive black holes are almost equal at a few times 10⁷ M_⊙. Additionally, we present a simple N-body simulation to shed some light on the initial conditions of the progenitor galaxies. We find that for an almost orthogonal approach of the two interacting galaxies, the model resembles the optical image of the system.