Tuesday, May 21, 2013

1305.4535 (D. Iono et al.)

Active Galactic Nucleus and Extended Starbursts in a Mid-stage Merger VV114    [PDF]

D. Iono, T. Saito, M. S. Yun, R. Kawabe, D. Espada, Y. Hagiwara, M. Imanishi, T. Izumi, K. Kohno, K. Motohara, K. Nakanishi, H. Sugai, K. Tateuchi, Y. Tamura, J. Ueda, Y. Yoshii
High resolution (0.4 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0 observations of HCO+(4-3) and HCN(4-3) toward a mid-stage infrared bright merger VV114 have revealed compact nuclear (<200 pc) and extended (3 - 4 kpc) dense gas distribution across the eastern part of the galaxy pair. We find a significant enhancement of HCN(4-3) emission in an unresolved compact and broad (290km/s) component found in the eastern nucleus of VV114, and we suggest dense gas associated with the surrounding material around an Active Galactic Nucleus (AGN), with a mass upper limit of < 4 x 10^8 Msun. The extended dense gas is distributed along a filamentary structure with resolved dense gas concentrations (230pc; 10^6 Msun) separated by a mean projected distance of 600 pc, many of which are generally consistent with the location of star formation traced in Pa alpha emission. Radiative transfer calculations suggest moderately dense (10^5 - 10^6 cm^-3) gas averaged over the entire emission region. These new ALMA observations demonstrate the strength of the dense gas tracers in identifying both the AGN and star formation activity in a galaxy merger, even in the most dust enshrouded environments in the local universe.
View original: http://arxiv.org/abs/1305.4535

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