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We identify a fading AGN SDSS J220141.64+115124.3 from the internal Product Launch-11 (MPL-11) in Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. The central region with a projected radius of |$\sim$| 2.4 kpc is characterized as LINER-like line ratios while the outskirts extended to |$\sim$| 15 kpc show Seyfert-like line ratios. The |${\rm{[O {\small III}]}}$| |$\lambda$| 5007 luminosity of the Seyfert regions is a factor of 37 (2) higher than the LINER regions without (with) dust attenuation correction, suggesting that the AGN activity decreases at least |$\sim$| 8 |$\times$| 10 |$^3$| yr (⁠|$\sim$| 2.4 kpc/light-speed) ago. We model the emission line spectra in the central region with double Gaussian components (a narrow core and a broad wing) and analyse the properties of each component. The narrow core component mostly co-rotates with the stellar disc, whereas the broad wing component with a median of the velocity dispersion |$\sim$| 300 km s |$^{-1}$| is related to a wind outflow. The kinematic position angle (PA) of the ionized gas shows an |$\sim 20^{\circ }$| twist from the galaxy centre to 1.5 effective radius. The median of the PA difference between the gas and stellar components is as large as |$\sim 50^{\circ }$| within 0.4 effective radius. The tidal feature in DESI image and star–gas misalignment suggest this galaxy is a merger remnant. Combining all these observational results as well as public available X-ray and MIR luminosities, we confirm this is a fading AGN, the merger process kick-started the central engine to quasar phase which ionized gas composed of tidal debris, and now the activity of the central black hole decreases. The discontinuity in |${\rm{[O {\small III}]}}$| |$\lambda$| 5007 flux and EQW maps is due to multiple AGN outbursts triggered by merger remnant gas inflows. [ABSTRACT FROM AUTHOR]

In this Letter, properties of black hole (BH) mass are well checked for the interesting object SDSS J0159, a changing-look active galactic nuclei and also a host galaxy of a tidal disruption event (TDE). Through spectral absorption features, the stellar velocity dispersion of SDSS J0159 can be well measured as |$\sigma \sim 81~{\rm km\, s}^{-1}$|⁠ , leading to SDSS J0159 being an apparent outlier in the M BH–σ space, because of the BH mass estimated through the M BH–σ relation about two magnitudes lower than the reported virial BH mass of about 108 M⊙. After considerations of contributions of stellar debris from the central TDE to broad line emission clouds, the overestimated virial BH mass could be well explained in SDSS J0159. Therefore, overestimated virial BH masses through broad-line properties in the M BH–σ space could be treated as interesting clues to support central TDEs. [ABSTRACT FROM AUTHOR]

Based on a large sample of 254 220 galaxies in 81 089 groups, which are selected from the spectroscopic galaxy sample of the Sloan Digital Sky Survey Data Release 12, we investigate the radial distribution of incidences, morphologies, environmental densities, and star formation properties of the active galactic nucleus (AGN) host galaxies and star-forming galaxies (SFGs) in the groups at |$z$| < 0.2, as well as their changes with group richness (N rich). It is found that AGN fraction slightly declines with richness for the groups/clusters. The SFG fraction is on average about two times larger than the AGN fraction, with a significant declining trend with richness. The group AGNs are preferentially reside in spheroidal and bulge-dominated disc galaxies, whereas the majority of SFGs are late-type discs. Compared with the SFGs, the AGNs in poor groups (5 ≤ N rich ≤ 10) are closer to group centre. The AGN fraction does not change with the distance to the group centre, whereas the SFG fraction tends to be higher in the outskirts. The AGNs in groups have a higher incidence than the SFGs for the massive (log (M */M⊙) > 10.7) galaxies, and the mean SFG fraction is about six times as that of AGNs in the late-type galaxies with lower masses at larger radius. The distribution of environmental luminosity densities shows that the AGNs are likely to be reside in a denser environment relative to the SFGs. Compared with the SFGs in groups, the group AGNs are found to have a higher mean stellar mass, a lower mean star formation rate, and an older mean stellar age. [ABSTRACT FROM AUTHOR]