The enormous amount of data collected by the Dark Energy Survey (DES) provide a great opportunity to explore low surface brightness science topics, such as faint diffuse light in galaxies and galaxy clusters. In this talk, I will describe how we study diffuse intra-cluster light through stacking the images of hundreds of galaxy clusters from DES, reaching a surface brightness limit of 30 mag/arcsec^2, out to a radial distance of 1 Mpc from the cluster center. Despite their low surface brightness, our studies show that intra-cluster light is a significant component of the galaxy cluster stellar content. The stacking method has also been applied to characterizing the light profiles of luminous red galaxies, as well as studying the aureole component of the DES point spread function. Weak lensing and precision photometry calibration  methods may wish to consider these effects in the future.

before I will discuss the results of AGN studies with Swift.

The Galactic center excess has lingered as a possible, but ambiguous, signal of new physics for several years. It has previously been argued that certain details of the excess emission imply that it likely originates from a population of point sources, but this remains a topic of vigorous debate. In this talk, I will report on my recent work, relying on a new point source catalog (obtained by the Fermi-LAT collaboration), that sheds light on this controversial topic. After giving some background on the excess, I will discuss various metrics that have been used to try to understand its true nature. I will show that the large majority of bright sources that were previously suggested to be members of the excess are indeed contained in the new Fermi-LAT point source catalog -- and yet, despite masking out these sources (so that they cannot contribute to the excess), the excess remains just as bright in our new fit to the data. I will go on to discuss the implications of our findings for the two most popular interpretations of the excess.