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Starburst or Seyfert? Using near-infrared spectroscopy to measure the activity in composite galaxies

Tanya L. Hill·Charlene A. Heisler·Ralph Sutherland·Richard W. Hunstead
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Abstract

We present near-infrared spectra for a sample of galaxies with ambiguous optical emission line ratios. These galaxies fall between starbursts and Seyferts in the usual optical diagnostic diagrams. We find a similar result with the near-infrared emission line ratios, which suggests that the galaxies are composite, containing both a starburst and AGN component. Furthermore, CO absorption, produced in late-type stars, is detected within the sample, although at a weaker level than is typical for starburst galaxies. We conclude that the CO feature is being diluted by a contribution from an AGN, thereby confirming the composite nature of these galaxies.

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Tanya L. Hill, Charlene A. Heisler, Ralph Sutherland, Richard W. Hunstead. 1998-10-23. Starburst or Seyfert? Using near-infrared spectroscopy to measure the activity in composite galaxies. https://doi.org/10.1086/300666

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