The optical-infrared colour distribution of a statistically complete sample of faint field spheroidal galaxies

F. Menanteau, R. S. Ellis, R. G. Abraham, A. J. Barger, L. L. Cowie

Research output: Contribution to journalArticlepeer-review


In hierarchical models, where spheroidal galaxies are primarily produced via a continuous merging of disc galaxies, the number of intrinsically red systems at faint limits will be substantially lower than in 'traditional' models where the bulk of star formation was completed at high redshifts. In this paper we analyse the optical-near-infrared colour distribution of a large flux-limited sample of field spheroidal galaxies identified morphologically from archival Hubble Space Telescope data. The I814 -HK′ colour distribution for a sample jointly limited at I814 < 23 mag and HK′ < 19.5 mag is used to constrain their star formation history. We compare visual and automated methods for selecting spheroidals from our deep HST images and, in both cases, detect a significant deficit of intrinsically red spheroidals relative to the predictions of high-redshift monolithic-collapse models. However, the overall space density of spheroidals (irrespective of colour) is not substantially different from that seen locally. Spectral synthesis modelling of our results suggests that high-redshift spheroidals are dominated by evolved stellar populations polluted by some amount of subsidiary star formation. Despite its effect on the optical-infrared colour, this star formation probably makes only a modest contribution to the overall stellar mass. We briefly discuss the implications of our results in the context of earlier predictions based on models where spheroidals assemble hierarchically.

Original languageEnglish (US)
Pages (from-to)208-220
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Oct 11 1999
Externally publishedYes


  • Galaxies: elliptical and lenticular, cD
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: photometry
  • Infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The optical-infrared colour distribution of a statistically complete sample of faint field spheroidal galaxies'. Together they form a unique fingerprint.

Cite this