Detailed accretion history of the supermassive black hole in NGC 5972 over the past $\gtrsim$10${}^4$ years through the extended emission line region

Abstract

We present integral field spectroscopic observations of NGC 5972 obtained with the Multi Unit Spectroscopic Explorer (MUSE) at VLT. NGC 5972 is a nearby galaxy containing both an active galactic nucleus (AGN), and an extended emission line region (EELR) reaching out to $\sim 17$ kpc from the nucleus. We analyze the physical conditions of the EELR using spatially-resolved spectra, focusing on the radial dependence of ionization state together with the light travel time distance to probe the variability of the AGN on $\gtrsim 10^4$ yr timescales. The kinematic analysis suggests multiple components: (a) a faint component following the rotation of the large scale disk; (b) a component associated with the EELR suggestive of extraplanar gas connected to tidal tails; (c) a kinematically decoupled nuclear disk. Both the kinematics and the observed tidal tails suggest a major past interaction event. Emission line diagnostics along the EELR arms typically evidence Seyfert-like emission, implying that the EELR was primarily ionized by the AGN. We generate a set of photoionization models and fit these to different regions along the EELR. This allows us to estimate the bolometric luminosity required at different radii to excite the gas to the observed state. Our results suggests that NGC 5972 is a fading quasar, showing a steady gradual decrease in intrinsic AGN luminosity, and hence the accretion rate onto the SMBH, by a factor $\sim 100$ over the past $5\times 10^4$ yr.

To be published in The Astrophysical Journal

References in corpus (16)

• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• The MUSE second-generation VLT instrument
• Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• The Many Routes to AGN Feedback
• Optical variability of AGN in the PTF/iPTF survey
• Extended Emission-Line Regions: Remnants of Quasar Superwinds?
• Fading AGN Candidates: AGN Histories and Outflow Signatures
• Sizes and Kinematics of Extended Narrow-Line Regions in Luminous Obscured AGN Selected by Broadband Images
• HST Imaging of Fading AGN Candidates I: Host-Galaxy Properties and Origin of the Extended Gas
• Storm in a "Teacup": a radio-quiet quasar with ~10kpc radio-emitting bubbles and extreme gas kinematics
• The Sudden Death of the Nearest Quasar
• Spatially-Resolved Spectra of the "Teacup" AGN: Tracing the History of a Dying Quasar
• X-ray spectral properties of seven heavily obscured Seyfert 2 galaxies

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• Finding of a population of active galactic nuclei showing a significant luminosity decline in the past $\sim 10^{3-4}$ yrs
• Jet-mode feedback in NGC 5972: insights from resolved MUSE, GMRT and VLA observations
• First resolved stellar halo kinematics of a MW-mass galaxy outside the Local Group: A flat counter-rotating halo in NGC 4945
• The luminosity history of fading local quasars over 10${}^{4-5}$ years as observed by VLT/MUSE