Low Surface-brightness Observations

I am an active member of the team running the Dragonfly telephoto array. This telescope, currently comprised of 48 Canon Telephoto lenses is optimized from the hardware through the processesing pipline to study the low surface brightness universe. Large, faint whispy features are often missed using traditional telescopes and can only be measured using specialized telescope like Dragonfly. I have focused on studying to outskirts of massive galaxies in the Dragonfly wide field survey .

We are not missing light in the outskirts of massive galaxies

Massive galaxies are integral to our understanding of galaxy formation however they are notoriously tricky to observe properly. They are known to have very extended low surface-brightness outskirts which contain a large fraction of their light (>10%). Using the data from Dragonfly, we specifically designed a photometry method designed to take advatage of the suberb low surface brightness sensitivity. We accurately measured the total flux and colors of nearby massive galaxies taking into account all the light in the outskirts. When comparing to common methods applied to SDSS, we find that our total flux measurement agree but DF measured bluer colors on average. This leads to the perplexing result that when accounting for the light in the outskirts with dragonfly we measure lower stellar masses the other techniques. These results are published in a paper that appeared in ApJ