Multiple AGN in the crowded field of the compact group SDSSJ0959+1259

TL;DR

This study investigates a compact galaxy group with the highest known concentration of active galactic nuclei, revealing multiple AGN types and signs of galaxy interactions, providing insights into nuclear activity triggers.

Contribution

First multi-wavelength analysis of SDSS J0959+1259, identifying a high fraction of active nuclei and evidence of galaxy interactions in a compact group.

Findings

High AGN fraction of 60% in the group.

Presence of multiple AGN types including Seyferts and LINERs.

Evidence of galaxy interactions through tidal distortions.

Abstract

We present a multi-wavelength study of a newly discovered compact group (CG), SDSS J0959+1259, based data from XMM-Newton, SDSS and the Calar Alto optical imager BUSCA. With a maximum velocity offset of 500 km s$^{-1}$, a mean redshift of 0.035, and a mean spatial extension of 480 kpc, this CG is exceptional in having the highest concentration of nuclear activity in the local Universe, established with a sensitivity limit L$_{X}>4\times $10$^{40}$ erg s$^{-1}$ in 2--10 keV band and R-band magnitude $M_R < -19$. The group is composed of two type-2 Seyferts, one type-1 Seyfert, two LINERs and three star forming galaxies. Given the high X-ray luminosity of LINERs which reaches $\sim 10^{41}$ erg s$^{-1}$, it is likely that they are also accretion driven, bringing the number of active nuclei in this group to to 5 out of 8 (AGN fraction of 60\%). The distorted shape of one member of the CG suggests that strong interactions are taking place among its galaxies through tidal forces. Therefore, this system represents a case study for physical mechanisms that trigger nuclear activity and star formation in CGs.