Search for gamma-ray emissions from AE Aquarii with Fermi LAT

AE Aquarii is a cataclysmic variable with the fastest known rotating magnetized white dwarf (P_{spin} = 33.08 s). We report on deep searches for gamma-ray emission and pulsations from AE Aquarii in seven years of Fermi-LAT Pass 8 data. Using different X-ray observations spanning 20 years, we substantially extended the timing ephemeris of AE Aquarii. A spin phase jump was discovered between MJD 55122.5 - 56078.64 by X-ray timing analysis. Using the extended timing ephemeris, we searched for gamma-ray pulsations at the spin period and its first harmonic. No gamma-ray pulsation were detected above 3 sigma significance. Neither steady gamma-ray emission nor gamma-ray variability of AE Aquarii were detected by Fermi-LAT. We impose the most restrictive upper limit on the gamma-ray emission from AE Aquarii to date, as 1.23×10^{-12} erg cm^{-2} s^{-1} in 0.1-300 GeV range providing constrains on models.