AAS 205th Meeting, 9-13 January 2005
Session 110 Active Galaxies
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[110.04] Slow Motions in the NGC 1275 (Perseus A) System of Giant Ionized Filaments

P. Cigan, J. Gallagher, E. Zweibel (Univ. Wisconsin-Madison)

Emission line strengths and velocities have been obtained at 5 positions in the NGC1275 emission line filaments system covering a range in radial distance. These observations taken with the Densepak fiber array at the Cassegrain focus of the WIYN 3.5-m telescope provide radial velocities with an rms precision of about 50 km/s. The spectra cover the H\alpha spectral region and include the [NII] and [SII] emission lines in all but the faintest regions. Our analysis of the filament radial velocity distribution of the ionized gas based on these data shows only a small velocity spread of about 350 km/s as compared with the sound speed in the intracluster medium (ICM) of >1000 km/s. The ionized filaments are effectively floating in the ICM. We discuss the implications of this result in terms of the origin of the filaments, and find support for models where the filaments consist of interstellar gas that was pulled out of the main body of NGC1275.

Research supported in part by NSF grant AST98-03018 to the University of Wisconsin-Madison and by our Graduate School through funds supplied by the Wisconsin Alumni Research Foundation.

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© 2004. The American Astronomical Society.