Gemini IFU, VLA, and HST observation of the OH Megamaser Galaxy IRAS17526+3253★

We present a multiwavelength study of the OH megamaser galaxy IRAS17526 + 3253, based on new Gemini multi-object spectrograph integral field unit (GMOS/IFU) observations, Hubble Space Telescope F814W, and H alpha + [N II] images, and archival 2MASS and 1.49 GHz VLA data. The Hubble Space Telescope (HST) images clearly reveal a mid-to-advanced stage major merger whose northwestern and southeastern nuclei have a projected separation of similar to 8.5 kpc. Our HST/H alpha + [N II] image shows regions of ongoing star formation across the envelope on similar to 10 kpc scales, which are aligned with radio features, supporting the interpretation that the radio emission originates from star-forming regions. The measured H alpha luminosities imply that the unobscured star formation rate (SFR) is similar to 10-30M(circle dot) yr(-1). The GMOS/IFU data reveal two structures in northwestern separated by 850 pc and by a discontinuity in the velocity field of similar to 200 km s(-1). We associate the blueshifted and redshifted components with, respectively, the distorted disc of northwestern and tidal debris, possibly a tail originating in southeastern. Star formation is the main ionization source in both components, which have SFRs of similar to 2.6-7.9M(circle dot) yr(-1) and similar to 1.5-4.5M(circle dot) yr(-1), respectively. Fainter line emission bordering thesemain components is consistent with shock ionization at a velocity similar to 200 km s(-1) and may be the result of an interaction between the tidal tail and the northwestern galaxy's disc. IRAS17526 + 3253 is one of only a few systems known to host both luminous OH and H2O masers. The velocities of the OH and H2O maser lines suggest that they are associated with the northwestern and southeastern galaxies, respectively (Martin et al.; Wagner).