Near-infrared line imaging of circumnuclear star formation in nearby active galaxies

J. K. Kotilainen*, J. Reunanen, S. Laine, S. D. Ryder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We present J H K, Brγ and H2 1-0 S(1) imaging of the circumnuclear star forming rings in the active galaxies NGC 1097 and NGC 7771. Their clumpy morphology varies with wavelength, due to extinction, emission from hot dust and red supergiants, and several stellar generations. The H2/Brγ ratios in the rings indicate the main excitation mechanism of the molecular gas to be UV radiation from hot young stars. Both galaxies exhibit similar small Bry equivalent widths. To explain the observations, we prefer a model of an instantaneous starburst occurring 6-7 Myr ago, as opposed to a constant star forming rate model. A gaseous nuclear bar aligned parallel to the stellar nuclear bar has been detected in NGC 1097, and we discuss the connection between the rings, bars and the fueling of nuclear activity.

Original languageEnglish
Pages (from-to)505-509
Number of pages5
JournalAstrophysics and Space Science
Publication statusPublished - 1 Dec 1999
Externally publishedYes


  • Star Form Rate
  • Initial Mass Function
  • Active Galaxy
  • Radio Spectral Index
  • Inner Lindblad Resonance


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