Serendipitous Discovery of an Optical Emission-line Jet in NGC 232

DOI: 
10.3847/2041-8213/aa98db
Publication date: 
01/11/2017
Main author: 
López-Cobá, C.
IAA authors: 
Sánchez-Menguiano, L.
Authors: 
López-Cobá, C.;Sánchez, S. F.;Cruz-González, I.;Binette, L.;Galbany, L.;Krühler, T.;Rodríguez, L. F.;Barrera-Ballesteros, J. K.;Sánchez-Menguiano, L.;Walcher, C. J.;Aquino-Ortíz, E.;Anderson, J. P.
Journal: 
The Astrophysical Journal
Refereed: 
Yes
Publication type: 
Article
Volume: 
850
Pages: 
L17
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 survey. This jet-like feature extends radially from the nucleus and is primarily detected in [O iii]λ5007 without clear evidence of an optical continuum counterpart. The length of the radial structure projected on sky reaches ∼3 kpc, which makes NGC 232 the second-longest emission-line jet reported. The ionized gas presents extreme [O iii]/Hβ and [N ii]/Hα line ratios, increasing along the jet-like structure. We discuss three possible scenarios to explain the observed structure: (i) direct ionization of infalling material from the intergalactic medium by the AGN, (ii) photoionization by an undetected optical counterpart of the radio jet, and (iii) fast shock ionization due to the lateral expansion of the radio jet across the interstellar medium. Our analysis favors in situ ionization.

Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85035328344&doi=10.3847%2f2041-8213%2faa98db&partnerID=40&md5=1d49d75c4d1733e100697eae634199a4
ADS Bibcode: 
2017ApJ...850L..17L
Keywords: 
galaxies: individual: NGC 232;galaxies: ISM;galaxies: jets;galaxies: spiral;ISM: jets and outflows;radio continuum: galaxies