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Title: Spatially resolved spectra of the 'teacup' active galactic nucleus: tracing the history of a dying quasar

The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a 'handle'-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] λ6716/λ6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by thismore » amount in a continuous fashion over 46,000 yr, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long timescale variability.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place South SE, Suite 600, Atlanta, GA 30303 (United States)
  2. Department of Physics, Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States)
  3. Naval Research Laboratory, Washington, DC 20375 (United States)
  4. Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States)
  5. Physics Department, Technion, Haifa 32000 (Israel)
  6. Physics Department, California Polytechnic State University San Luis Obispo, CA 93407 (United States)
  7. Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)
Publication Date:
OSTI Identifier:
22365174
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BOLOMETERS; COSMIC RADIATION; DENSITY; EMISSION; GALAXIES; GALAXY NUCLEI; HYDROGEN; LUMINOSITY; PHOTOIONIZATION; QUASARS; SIMULATION; SPECTRA; SPECTROSCOPY; TELESCOPES