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arXiv · 1711.02785

Serendipitous discovery of an optical emission line jet in NGC\,232

C. Lopez-Coba·S. F. Sanchez·I. Cruz-Gonzalez·L. Binette·L. Galbany·T. Kruhler·L. F. Rodrıguez·J. K. Barrera-Ballesteros·L. Sanchez-Menguiano·C. J. Walcher·E. Aquino-Ortız·J. P. Anderson
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Abstract

We report the detection of a highly collimated linear emission-line structure in the spiral galaxy NGC\,232 through the use of integral field spectroscopy data from the All-weather MUse Supernova Integral field Nearby Galaxies (AMUSING) survey. This jet--like feature extends radially from the nucleus and is primarily detected in [oiii]$\lambda$5007 without clear evidence of an optical continuum counterpart. The length of the radial structure projected on sky reaches $\sim 3$ kpc, which makes NGC\,232 the second longest emission-line jet reported. The ionized gas presents extreme [Oiii]/H$\beta$ and [Nii]/H$\alpha$ line ratios, increasing along the jet-like structure. We discuss three possible scenarios to explain the observed structure: (i) direct ionization of in-falling material from the intergalactic medium by the AGN; (ii) photo-ionization by an un-detected optical counter-part of the radio jet and (iii) fast shocks ionization due to the lateral expansion of the radio jet across the ISM. Our analysis favors in-situ ionization.

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C. Lopez-Coba, S. F. Sanchez, I. Cruz-Gonzalez, L. Binette, L. Galbany, T. Kruhler, L. F. Rodrıguez, J. K. Barrera-Ballesteros, L. Sanchez-Menguiano, C. J. Walcher, E. Aquino-Ortız, J. P. Anderson. 2017-11-08. Serendipitous discovery of an optical emission line jet in NGC\,232. https://doi.org/10.3847/2041-8213/aa98db

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