The Halos and Environments of Nearby Galaxies (HERON) I: Imaging, Sample
  Characteristics, and Envelope Diameters
  We use a dedicated 0.7-m telescope to image the halos of 119 galaxies in the
Local Volume to $\mu_r \sim 28-30$ mag/arcsec$^2$. The sample is primarily from
the 2MASS Large Galaxy Atlas and extended to include nearby dwarf galaxies and
more distant giant ellipticals, and spans fully the galaxy colour-magnitude
diagram including the blue cloud and red sequence. We present an initial
overview, including deep images of our galaxies. Our observations reproduce
previously reported low surface brightness structures, including extended
plumes in M51, and a newly discovered tidally extended dwarf galaxy in NGC7331.
Low surface brightness structures, or "envelopes", exceeding 50 kpc in diameter
are found mostly in galaxies with $M_V<-20.5$, and classic interaction
signatures are infrequent. Defining a halo diameter at the surface brightness
28 mag/arcsec$^2$, we find that halo diameter is correlated with total galaxy
luminosity. Extended signatures of interaction are found throughout the galaxy
colour-magnitude diagram without preference for the red or blue sequences, or
the green valley. Large envelopes may be found throughout the colour-magnitude
diagram with some preference for the bright end of the red sequence. Spiral and
S0 galaxies have broadly similar sizes, but ellipticals extend to notably
greater diameters, reaching 150 kpc. We propose that the extended envelopes of
disk galaxies are dominated by an extension of the disk population rather than
by a classical population II halo.
