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Session 105 - Galaxies: Counts & Kinematics.
Display session, Saturday, January 10
Exhibit Hall,

[105.12] Metallicities of Tidal Dwarf Candidates in the Debris of Hickson Compact Groups

A. D. Glenn, S. D. Hunsberger, J. C. Charlton, R. B. Ciardullo (Penn State), D. Zaritsky (UCSC/Lick)

Moderately deep CCD images of Hickson compact groups have shown the existence of extended objects in the tidal tails of these groups. Hunsberger et al. (1996) indicate that these extended objects are likely to be drawf galaxies. To test this theory and determine the nature of these objects, long slit spectra have been obtained, and relative fluxes in important emission lines have been measured. From these fluxes, the metallicities and densities of the objects are inferred. Metallicity is computed using the O/H ratio ([O II]\lambda\lambda3726,3729 + [O III]\lambda\lambda4959,5007) / H\beta, and the density is determined using the ratio [S II]\lambda6716 / [S II]\lambda6731. The metallicities of the tidal dwarf candidates are compared with the expected metallicities for dwarf galaxies and the metallicities of the outskirts of their parent spiral galaxies. Also, the relationship between metallicity and the relative position of the objects in the tidal debris is explored. The spectra of these ojects are presented along with the metallicity and density results.

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