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The Discovery of a Giant H-alpha Filament in NGC 7213

Salman Hameed·David Blank·Lisa Young·Nick Devereux
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Abstract

The nearby Seyfert galaxy NGC 7213 has been imaged in H-alpha and HI with the CTIO 1.5 m telescope and with the Australia Telescope Compact Array (ATCA), respectively. Optically NGC 7213 looks undisturbed and relatively featureless but the continuum-subtracted H-alpha image shows a 19 kpc long filament located approximately 18.6 kpc from the nucleus. The H-alpha filament could be neutral gas photo-ionized by the active nucleus, as has been suggested for the Seyfert galaxy NGC 5252, or shock-ionized by a jet interacting with the surrounding HI, as has been suggested for the radio galaxy PKS 2240-41. The HI map reveals NGC 7213 to be a highly disturbed system suggesting a past merging event.

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Salman Hameed, David Blank, Lisa Young, Nick Devereux. 2000-11-10. The Discovery of a Giant H-alpha Filament in NGC 7213. https://doi.org/10.1086/318865

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