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K. Menendez-Delmestre, A. W. Blain, S. C. Chapman (California Institute of Technology), A. M. Swinbank, I. Smail (Institute of Computational Cosmology, University of Durham, UK), R. J. Ivison (Astronomy Technology Center, Royal Observatory, Edinburgh; Institute of Astronomy, University of Edinburgh, UK), D. M. Alexander (Institute of Astronomy, University of Cambridge, UK)
We used the OH-Suppresing Infrared Imaging Spectrograph (OSIRIS) on Keck II with laser AO to investigate the internal dynamics of two of the most luminous submillimeter galaxies (SMGs) at redshifts z~2-3: SMM J030227.73+000653.5 at z=1.408 and SMM J221804.42+002154.4 at z=2.517 (Chapman et al. 2005). Recent ultradeep Chandra X-ray results indicate that the majority of SMGs contain an actively fueled AGN (Alexander et al. 2005), as their hard X-ray emission is too powerful to be explained by the high-mass X-ray binaries associated with pure star formation. This AGN contributes a minor fraction to the total luminosity, but the potential modifies the observed spectra, complicating their interpretation in terms of excitation and metallicity. We expect the restframe optical light from this nuclear emission to be centrally concentrated, surrounded by a more extended emission from star-forming regions. With AO we attempt to resolve the separation between the nuclear and extended emission, to probe the AGN and the velocity field of the wider starburst. We aimed to map the two-dimensional spatial distribution of H-alpha line emission, using the appropriate narrow band filters Hn2 and Kn5 matched to our known redshifts using the coarsest OSIRIS plate scale (0.1-arcsec) to have the largest field of view and optimize the coverage of the luminous region of the galaxies. By measuring accurately both the velocity dispersion point-by-point and the physical extent of these high redshift galaxies, we can estimate their dynamical masses. This enables us to better understand their internal astrophysics, their fate in terms of the galaxies we observe today, and the links between properties of dark matter halos and the stellar systems that form within. We thank NASA, NSF and Sloan Foundation.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.