Luminous, pc-scale CO 6−5 emission in the obscured nucleus of NGC 1377
Résumé
High-resolution submillimeter line and continuum observations are important in probing the morphology, column density, and dynamics of the molecular gas and dust around obscured active galactic nuclei (AGNs). With high-resolution (0.̋06 × 0.̋05 (6 × 5 pc)) ALMA 690 GHz observations we have found bright (TB > 80 K) and compact (full width half maximum size (FWHM) size of 10 × 7 pc) CO 6-5 line emission in the nuclear region of the extremely radio-quiet galaxy NGC 1377. The CO 6-5 intensity is partially aligned with the previously discovered jet/outflow of NGC 1377 and is tracing dense (n > 104cm-3) hot molecular gas at the base of the outflow. The velocity structure is complex and shifts across the jet/outflow are discussed in terms of separate overlapping kinematical components or rotation. High-velocity gas (Deltav ± 145km s-1) is detected inside r < 2-3 pc and we suggest that it is emerging from an inclined rotating disk or torus of position angle PA = 140° ± 20° with a dynamical mass of 3 × 106M&sun;. This mass is consistent with that of a supermassive black hole (SMBH), as inferred from the M-sigma relation. The gas mass of the proposed disk/torus constitutes
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