NGC 5084: A massive disk galaxy accreting its satellites?

The spectra of 34 galaxies within 20 arcmin (similar to 100 kpc) of the lenticular galaxy NGC 5084 have been obtained using the FOCAP system on the Anglo-Australian 3.9 m telescope. Nine objects are found with projected separations less than or equal to 80 kpc and with radial velocities within +/-630 km s(-1) of the parent galaxy redshift. Using various techniques, their velocity differences and projected separations are used to estimate the mass of this SO galaxy, which ranges from 6X10(12)M. to 1X10(13)M.. With such a mass, NGC 5084 is one of the most massive disk galaxy known, with a (M/L-B)greater than or similar to 200M./L.. In agreement with the models' predictions of Quinn gr Goodman [ApJ, 309, 472 (1986)] but contrary to the results of Zaritsky et al. [ApJ, 405, 464 (1993)] obtained from their statistical sample, the properties of the satellites: population show no evidence for the ''Holmberg effect'' and a clear excess of satellites in retrograde orbits. Several signs hint that this SO galaxy has survived the accretion of several satellites. (C) 1997 American Astronomical Society.