MORE SATELLITES OF SPIRAL GALAXIES

We present a revised and expanded catalog of satellite galaxies of a s et of isolated spiral galaxies similar in luminosity to the Milky Way. This sample of 115 satellites, 69 of which were discovered in our mul tifiber redshift survey, is used to probe the results obtained from th e original sample further (Zaritsky et al.). The satellites are, by de finition, at projected separations less than or similar to 500 kpc, ha ve absolute recessional velocity differences with respect to the paren t spiral of less than 500 km s(-1), and are at least 2.2 mag fainter t han their associated primary galaxy. A key characteristic of this surv ey is the strict isolation of these systems, which simplifies any dyna mical analysis. We find no evidence for a decrease in the velocity dis persion of the satellite system as a function of radius out to galacto centric radii of 400 kpc, which suggests that the halo extends well be yond 200 kpc. Furthermore, the new sample affirms our previous conclus ions (Zaritsky et al.) that (1) the velocity difference between a sate llite and its primary is not strongly correlated with the rotation spe ed of the primary, (2) the system of satellites has a slight net rotat ion (34 +/- 14 km s(-1)) in the same sense as the primary's disk, and (3) that the halo mass of an similar to L spiral galaxy is in excess of 2 x 10(12) M..