Shocked gas in IRAS F17207-0014: ISM collisions and outflows

April 2015 • 2015MNRAS.448.2301M

Authors • Medling, Anne M. • U, Vivian • Rich, Jeffrey A. • Kewley, Lisa J. • Armus, Lee • Dopita, Michael A. • Max, Claire E. • Sanders, David • Sutherland, Ralph

Abstract • We combine optical and near-infrared adaptive optics-assisted integral field observations of the merging ultraluminous infrared galaxies IRAS F17207-0014 from the Wide-Field Spectrograph and Keck/OH-Suppressing Infra-Red Imaging Spectrograph (OSIRIS). The optical emission line ratios [N II]/Hα, [S II]/Hα, and [O I]/Hα reveal a mixing sequence of shocks present throughout the galaxy, with the strongest contributions coming from large radii (up to 100 per cent at ∼5 kpc in some directions), suggesting galactic-scale winds. The near-infrared observations, which have approximately 30 times higher spatial resolution, show that two sorts of shocks are present in the vicinity of the merging nuclei: low-level shocks distributed throughout our field-of-view evidenced by an H₂/Brγ line ratio of ∼0.6-4, and strong collimated shocks with a high H₂/Brγ line ratio of ∼4-8, extending south from the two nuclear discs approximately 400 pc (∼0.5 arcsec). Our data suggest that the diffuse shocks are caused by the collision of the interstellar media associated with the two progenitor galaxies and the strong shocks trace the base of a collimated outflow coming from the nucleus of one of the two discs.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2015MNRAS.448.2301M
• PDF https://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/stv081
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2015MNRAS.448.2301M
• PREPRINT http://arxiv.org/abs/1501.07289
• ELECTR https://doi.org/10.1093%2Fmnras%2Fstv081