Spitzer mips infrared imaging of M31: Further evidence for a spiral-ring composite structure

K. D. Gordon, J. Bailin, C. W. Engelbracht, G. H. Rieke, K. A. Misselt, W. B. Latter, E. T. Young, M. L.N. Ashby, P. Barmby, B. K. Gibson, D. C. Hines, J. Hinz, O. Krause, D. A. Levine, F. R. Marleau, A. Noriega-Crespo, S. Stolovy, D. A. Thilker, M. W. Werner

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


New images of M31 at 24, 70, and 160 μm taken with the Multiband Imaging Photometer for Spitzer (MIPS) reveal the morphology of the dust in this galaxy. This morphology is well represented by a composite of two logarithmic spiral arms and a circular ring (radius ∼10 kpc) of star formation offset from the nucleus. The two spiral arms appear to start at the ends of a bar in the nuclear region and extend beyond the star-forming ring. As has been found in previous work, the spiral arms are not continuous, but composed of spiral segments. The star-forming ring is very circular except for a region near M32 where it splits. The lack of well-defined spiral arms and the prominence of the nearly circular ring suggest that M31 has been distorted by interactions with its satellite galaxies. Using new dynamical simulations of M31 interacting with M32 and NGC 205, we find that, qualitatively, such interactions can produce an offset, split ring like that seen in the MIPS images.

Original languageEnglish (US)
Pages (from-to)L87-L92
JournalAstrophysical Journal
Issue number2 II
StatePublished - Feb 20 2006


  • Galaxies: ISM -
  • Galaxies: individual (M31, M32, NGC 205) -
  • Galaxies: spiral

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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