Speaker
Description
We report the possible detection of pulsed 𝛾-ray emission from one confirmed white dwarf
pulsar J191213.72-441045.1 and a candidate white dwarf pulsar EUVE J0317-85.5 using ∼15
years of data from the Fermi-LAT observatory. Pulsed 𝛾-ray emission in the 0.5-10 GeV energy
range from J191213.72-441045.1 were found at a period of 𝑃=319.99±0.35s with a -log(Pr)=6.76 which corresponds to a significance of ∼5.74𝜎. The phase-folded 𝛾-ray light curve on this period is remarkably in phase with the recent optical observations (Pelisoli et al. (2023a), Pelisoli et al. (2023b)) of J191213.72-441045.1 signifying that the pulsed 𝛾-rays and optical photons might be emanating from the same region in J191213.72-441045.1. Pulsed 𝛾-ray emission in the 0.5-10 GeV energy range were also found from the isolated, highly magnetic white dwarf EUVE J0317-85.5 at the period of 𝑃=724.65±0.54s with a -log(Pr)=5.02 which corresponds to significance of ∼4.01𝜎. The phase-folded 𝛾-ray light curve on this period is also in phase with recent optical observations of EUVE J0317-85.5 using the BOOTES-6 robotic telescope. We propose that the pulsed 𝛾-ray emission in the 0.5-10 GeV energy range from both of these fast spinning, magnetic white dwarfs is likely produced by the curvature radiation mechanism based on a recent study done by Meintjes et al. (2023) suggesting that fast spinning, magnetic white dwarfs to be possible low-level 𝛾-ray emitters.
