Multiwavelength study of the nuclei of a volume-limited sample of galaxies - II. Optical, infrared and radio observations

P. Lira, R. A. Johnson, A. Lawrence, R. Cid Fernandes

Research output: Contribution to journalArticlepeer-review

Abstract

We present optical and infrared broad-band images, radio maps, and optical spectroscopy for the nuclear region of a sample of nearby galaxies. The galaxies have been drawn from a complete volume-limited sample for which we have already presented X-ray imaging. We modelled the stellar component of the spectroscopic observations to determine the star formation history of our targets. Diagnostic diagrams were used to classify the emission-line spectra and determine the ionizing mechanism driving the nuclear regions. All those sources classified as active galactic nuclei present small Eddington ratios (~10-3 -10-6), implying a very slow growth rate of their black holes. We finally investigate the relative numbers of active and normal nuclei as a function of host galaxy luminosity and find that the fraction of active galaxies slowly rises as a function of host absolute magnitude in the MB ~ -12 to -22 range.
Original languageEnglish
Pages (from-to)1552-1590
JournalMonthly Notices of the Royal Astronomical Society
Volume382
Publication statusPublished - 1 Dec 2007

Keywords

  • galaxies: nuclei
  • galaxies: general
  • galaxies: active

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