Simulating disc galaxy bulges that are consistent with observed scaling relations

C. R. Christensen, Alyson Brooks, D. B. Fisher, F. Governato, J. McCleary, T. R. Quinn, S. Shen, J. Wadsley

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30 Scopus citations


We present a detailed comparison between the photometric properties of the bulges of two simulated galaxies and those of a uniform sample of observed galaxies. This analysis shows that the simulated galaxies have bulges with realistic surface brightnesses for their sizes and magnitude. These two field disc galaxies have rotational velocities ̃100 km s-1 and were integrated to a redshift of zero in a fully cosmological δ cold dark matter context as part of high-resolution smoothed particle hydrodynamic simulations. We performed bulge- disc decompositions of the galaxies using artificial observations, in order to conduct a fair comparison to observations. We also dynamically decomposed the galaxies and compared the star formation histories of the bulges to those of the entire galaxies. These star formation histories showed that the bulges were primarily formed before z = 1 and during periods of rapid star formation. Both galaxies have large amounts of early star formation, which is likely related to the relatively high bulge-to-disc ratios also measured for them. Unlike almost all previous cosmological simulations, the realistically concentrated bulges of these galaxies do not lead to unphysically high rotational velocities, causing them to naturally lie along the observed Tully-Fisher relation.

Original languageEnglish (US)
Pages (from-to)L51-L55
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - Feb 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Bulges
  • Formation
  • Galaxies
  • Methods
  • Numerical
  • Spiral
  • Structure

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    Christensen, C. R., Brooks, A., Fisher, D. B., Governato, F., McCleary, J., Quinn, T. R., Shen, S., & Wadsley, J. (2014). Simulating disc galaxy bulges that are consistent with observed scaling relations. Monthly Notices of the Royal Astronomical Society: Letters, 440(1), L51-L55.