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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

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University of Massachusetts Amherst

1999

Galaxies: individual (Arp 220)

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Full-Text Articles in Physical Sciences and Mathematics

Counterrotating Nuclear Disks In Arp 220, K Sakamoto, N Z. Scoville, Min S. Yun, M Crosas, R Genzel, L J. Tacconi Jan 1999

Counterrotating Nuclear Disks In Arp 220, K Sakamoto, N Z. Scoville, Min S. Yun, M Crosas, R Genzel, L J. Tacconi

Min S. Yun

The ultraluminous infrared galaxy Arp 220 has been observed at 0farcs5 resolution in CO (2-1) and 1 mm continuum using the newly expanded Owens Valley Millimeter Array. The CO and continuum peaks at the double nuclei and the surrounding molecular gas disk are clearly resolved. We find steep velocity gradients across each nucleus (ΔV~500 km s-1 within r=0farcs3) whose directions are not aligned with each other and with that of the outer gas disk. We conclude that the double nuclei have their own gas disks (r~100 pc), are counterrotating with respect to each other, and are embedded in the outer …