The variability of Seyfert 1.8 and 1.9 galaxies at 1.6 microns

A. C. Quillen, Shanna Shaked, A. Alonso-Herrero, Colleen McDonald, Ariane Lee, M. J. Rieke, G. H. Rieke

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We present a study of Seyfert 1.5-2.0 galaxies observed at two epochs with the Rubble Space Telescope (HST) at 1.6 μm. We find that unresolved nuclear emission from nine of 14 nuclei varies at the level of 10%-40% on timescales of 0.7-14 months, depending upon the galaxy. A control sample of Seyfert galaxies lacking unresolved sources and galaxies lacking Seyfert nuclei show less than 3% instrumental variation in equivalent aperture measurements. This proves that the unresolved sources are nonstellar and associated with the central parsecs of active galactic nuclei. Unresolved sources in Seyfert 1.8 and 1.9 galaxies are not usually detected in HST optical surveys; however, high angular resolution infrared observations will provide a way to measure time delays in these galaxies.

Original languageEnglish (US)
Pages (from-to)L17-L20
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Mar 20 2000


  • Galaxies: Seyfert
  • Galaxies: active
  • Galaxies: nuclei
  • Infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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