THE [O III] NEBULA OF THE MERGER REMNANT NGC 7252: A LIKELY FAINT IONIZATION ECHO*

@article{Schweizer2013THEI,
  title={THE [O III] NEBULA OF THE MERGER REMNANT NGC 7252: A LIKELY FAINT IONIZATION ECHO*},
  author={François Schweizer and Patrick Seitzer and Daniel D. Kelson and Edward V. Villanueva and G. Aniano Carnegie Observatories and University of Michigan and Steward Observatory},
  journal={The Astrophysical Journal},
  year={2013},
  volume={773},
  pages={148}
}
We present images and spectra of a ~10?kpc-sized emission-line nebulosity discovered in the prototypical merger remnant NGC?7252 and dubbed the [O III] nebula because of its dominant [O III] ?5007 line. This nebula seems to yield the first sign of episodic active galactic nucleus (AGN) activity still occurring in the remnant, ~220?Myr after the coalescence of two gas-rich galaxies. Its location and kinematics suggest it belongs to a stream of tidal-tail gas falling back into the remnant. Its… 

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