Seminar

Substantial Variation in the Stellar Halos of Spiral Galaxies

The Dragonfly Telephoto Array, comprised of 48 individual Canon telephoto lenses operating together as a single telescope, is an innovative approach to low surface brightness imaging. Sub-nanometer coatings on each optical element reduce scattered light from nearby bright stars and compact galaxy centers -- typically a key obstacle for integrated light observations -- by an order of magnitude, and Dragonfly's large field of view (2 x 2.6 degrees for a single frame) provides a large-scale view of galactic stellar halos and satellite systems. Using extremely deep (>30 mag/arcsec^2) optical imaging in g and r bands from the Dragonfly Nearby Galaxies Survey (DNGS), we have characterized the stellar halos of a sample of nearby luminous galaxies. I will present measurements of the stellar halo mass fractions of an initial sample of spiral galaxies from the survey, and discuss these in the context of the assembly histories of individual galaxies.

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