Resolved OH megamaser emission in the nuclear region of the ultraluminous infrared galaxy Markarian 273 |
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| Authors: | J A Yates A M S Richards M M Wright J L Collett M D Gray D Field R J Cohen |
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| Institution: | Division of Physics and Astronomy, Department of Physical Sciences, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB;NRAL, University of Manchester, Jodrell Bank, Cheshire SK11 9DL;Department of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL;School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS;Department of Physics and Astronomy, University of Wales, Cardiff CF2 3YB;Intsitute of Physics and Astronomy, University of Aarhus, DK-8000, Aarhus C, Denmark |
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| Abstract: | We present high angular resolution MERLIN observations of the 18-cm OH maser and continuum emission associated with the active core of the ultraluminous infrared galaxy Markarian 273. The continuum emission comes from three distinct regions in the central arcsecond of the galaxy. The brightest region of emission has a double-peaked structure which is spatially coincident with similar structures observed at 6 cm and 2.2 μm. The peak of the OH maser emission is spatially coincident with the peak in the continuum. For the first time the maser emission is spatially resolved, allowing us to measure the gas motion within the central 100 pc of the galaxy. Maser emission is found in both the 1665- and 1667-MHz lines, with no systematic offset found in the spatial locations of the two lines. The brighter component of the maser emission shows ordered motion and is aligned along the axis of the double-peaked structure in the brightest continuum region. The gas motion enables us to estimate the central mass density to be 850±50 M⊙ pc?3, which corresponds to a total mass of ≈1.5×108 M⊙. |
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| Keywords: | masers ISM: molecules galaxies: individual: Markarian 273 galaxies: ISM galaxies: nuclei radio lines: galaxies |
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