Gemini Multi-Object Spectrograph Integral Field Spectroscopy of a Merging System with Enhanced Balmer Absorption

In this paper we present the three dimensional dynamics of the galaxy SDSSJ101345.39+011613.66, selected for its unusually strong Balmer absorption lines(Wo(H-delta)=7.5A). Using the GMOS-South IFU in Nod & Shuffle mode we havemapped the continuum and optical absorption lines of this z=0.1055 fieldgalaxy. This galaxy has a disturbed morphology, with a halo of diffuse materialdistributed asymmetrically toward the north. Using the [OII] emission line(Wo([OII])=4.1A) we find that the gas and hot OB stars are offset from theolder stars in the system. The gas also has a spatially extended and elongatedmorphology with a velocity gradient of 100+/-20km/s across 6kpc in projection.Using the strong H-gamma and H-delta absorption lines we find that the A- starsare widely distributed across the system and are not centrally concentratedarguing that the A-star population has formed in molecular clouds outside thenucleus. By cross correlating the spectra from the datacube with an A-startemplate we find evidence that the A-star population has a 40km/s shear in thesame direction as the gas. The disturbed morphology, strong colour gradientsand strong H-delta and H-gamma absorption lines in SDSS J101345.39 argue thatthis is a recent tidal interaction/merger between a passive elliptical andstar-forming galaxy. Although based on a single object, these results show thatwe can spatially resolve and constrain the dynamics of this short lived (yetimportant) phase of galaxy formation in which the evolutionary process takegalaxies from star-forming to their quiescent end products.Comment: 7 pages, 7 figures. Accepted for publication in Ap