Looking for Stars and Finding the Moon: Effects of Lunar Gamma-ray Emission on Fermi LAT Light Curves

Understand

We are conducting a search for new gamma-ray binaries by making high signal-to-noise light curves of all cataloged Fermi LAT sources and searching for periodic variability using appropriately weighted power spectra.

• The light curves are created using a variant of aperture photometry where photons are weighted by the probability that they came from the source of interest.
• From this analysis we find that the light curves of a number of sources near the ecliptic plane are contaminated by gamma-ray emission from the Moon.
• This shows itself as modulation on the Moon's sidereal period in the power spectra.