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A fundamental plane of spiral structure in disk galaxies

Research output: Contribution to journalArticlepeer-review

  • Benjamin L. Davis
  • Daniel Kennefick
  • Julia Kennefick
  • Kyle B. Westfall
  • Douglas W. Shields
  • Russell Flatman
  • Matthew T. Hartley
  • Joel C. Berrier
  • Thomas P. K. Martinsson
  • Rob A. Swaters

Spiral structure is the most distinctive feature of disk galaxies and yet debate persists about which theory of spiral structure is correct. Many versions of the density wave theory demand that the pitch angle be uniquely determined by the distribution of mass in the bulge and disk of the galaxy. We present evidence that the tangent of the pitch angle of logarithmic spiral arms in disk galaxies correlates strongly with the density of neutral atomic hydrogen in the disk and with the central stellar bulge mass of the galaxy. These three quantities, when plotted against each other, form a planar relationship that we argue should be fundamental to our understanding of spiral structure in disk galaxies. We further argue that any successful theory of spiral structure must be able to explain this relationship.

Original languageEnglish
Article numberL13
JournalAstrophysical Journal Letters
Issue number1
Publication statusPublished - 24 Mar 2015


  • Davis_2015_ApJL_802_L13

    Rights statement: Reproduced by permission of the AAS.

    Final published version, 375 KB, PDF document

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