Quantifying the (X/peanut)-shaped structure in edge-on disc galaxies: length, strength, and nested peanuts

  title={Quantifying the (X/peanut)-shaped structure in edge-on disc galaxies: length, strength, and nested peanuts},
  author={Bogdan C. Ciambur and Alister W. Graham},
  journal={Monthly Notices of the Royal Astronomical Society},
  • B. Ciambur, A. Graham
  • Published 29 February 2016
  • Physics
  • Monthly Notices of the Royal Astronomical Society
X-shaped or peanut-shaped (X/P) bulges are observed in more than 40% of (nearly) edge-on disc galaxies, though to date a robust method to quantify them is lacking. Using Fourier harmonics to describe the deviation of galaxy isophotes from ellipses, we demonstrate with a sample of 11 such galaxies (including NGC 128) that the sixth Fourier component ($B_6$) carries physical meaning by tracing this X/P structure. We introduce five quantitative diagnostics based on the radial $B_6$ profile, namely… 
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