Abstract
We present high quality spectroscopic observations of a sample of 14 low ionization nuclear emission-line regions (LINERs). Starlight removal is achieved by the subtraction of a suitable absorption-line “template” galaxy, allowing accurate measurements of emission lines. We use these line fluxes to examine the possible excitation mechanisms of LINERs. We suggest that LINERs with weak [O I] λ 6300 emission ([O I]/Hα < 1/6) may beH II regions photoionized by unusually hot O-type stars. LINERs with [O I]/Hα < 1/6 may be powered by photoionization from a nonstellar continuum. This is supported by the detection of broad hα emission, a correlation between line width and critical density, and point-like X-ray emission in several of these objects.
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Ho, L.C., Filippenko, A.V. The photoionization mechanism of LINERs: stellar and nonstellar. Astrophys Space Sci 205, 19–27 (1993). https://doi.org/10.1007/BF00657952
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DOI: https://doi.org/10.1007/BF00657952