Giant Galaxies, Dwarfs, and Debris Survey. I. Dwarf Galaxies and Tidal
  Features Around NGC 7331
  The Giant GAlaxies, Dwarfs, and Debris Survey concentrates on the nearby
universe to study how galaxies have interacted in groups of different
morphology, density, and richness. In these groups we select the dominant
spiral galaxy and search its surroundings for dwarf galaxies and tidal
interactions. This paper presents the first results from deep wide-field
imaging of NGC 7331, where we detect only four low luminosity candidate dwarf
companions and a stellar stream that may be evidence of a past tidal
interaction. The dwarf galaxy candidates have surface brightnesses of mu_{r} ~
23-25 mag/arcsec^{2} with (g-r) colors of 0.57-0.75mag in the Sloan Digital Sky
Survey filter system, consistent with their being dwarf spheroidal galaxies
(dSph). A faint stellar stream structure on the western edge of NGC 7331 has
mu_{g} ~27 mag/arcsec^{2} and a relatively blue color of (g-r)=0.15mag. If it
is tidal debris, then this stream could have probably formed from a rare type
of interaction between NGC 7331 and a dwarf irregular or transition-type dwarf
galaxy. We compare the structure and local environments of NGC 7331 to those of
other nearby giant spirals in small galaxy groups. NGC 7331 has a much lower
(2%) stellar mass in the form of early-type satellites than found for M31 and
lacks the presence of nearby companions like luminous dwarf elliptical galaxies
or the Magellanic Clouds. However, our detection of a few dSph candidates
suggests that it is not deficient in low-luminosity satellites.
