The dragonfly nearby galaxies survey. Iv. A giant stellar disk in ngc
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  Neutral gas is commonly believed to dominate over stars in the outskirts of
galaxies, and investigations of the disk-halo interface are generally
considered to be in the domain of radio astronomy. This may simply be a
consequence of the fact that deep HI observations typically probe to a lower
mass surface density than visible wavelength data. This paper presents low
surface brightness optimized visible wavelength observations of the extreme
outskirts of the nearby spiral galaxy NGC 2841. We report the discovery of an
enormous low-surface brightness stellar disk in this object. When azimuthally
averaged, the stellar disk can be traced out to a radius of $\sim$70 kpc (5
$R_{25}$ or 23 inner disk scale lengths). The structure in the stellar disk
traces the morphology of HI emission and extended UV emission. Contrary to
expectations, the stellar mass surface density does not fall below that of the
gas mass surface density at any radius. In fact, at all radii greater than
$\sim$20 kpc, the ratio of the stellar to gas mass surface density is a
constant 3:1. Beyond $\sim$30 kpc, the low surface brightness stellar disk
begins to warp, which may be an indication of a physical connection between the
outskirts of the galaxy and infall from the circumgalactic medium. A
combination of stellar migration, accretion and in-situ star formation might be
responsible for building up the outer stellar disk, but whatever mechanisms
formed the outer disk must also explain the constant ratio between stellar and
gas mass in the outskirts of this galaxy.
