Speaker
Ms
Yi Xing
(yixing@shao.ac.cn)
Description
We report our search for γ-ray emission in the energy range from 100 MeV to 300 GeV from four Accreting Millisecond Pulsars (AMPs), SAX J1808.4−3658, IGR J00291+5934, XTE J1814−338, and XTE J0929−314, with four-year observations of Large Area Telescope (LAT) onboard the Fermi γ-ray Space Telescope. The AMPs were not detected. We obtained their γ-ray luminosity upper limits and compared with γ-ray irradiation luminosities required for producing optical modulations seen from their companions suggested by Takata et al. (2012). The upper limits have excluded γ-ray emission as the heating source in these systems except XTE J0929−314. Our results also do not support the model proposed by Takata et al. (2012) that relatively strong γ-ray emission could arise from the outer gap of a high-mass neutron star controlled by the photon-photon pair-creation for the AMPs. For SAX J1808.4−3658 and IGR J00291+5934, we derive the upper limits of their γ-ray conversion efficiencies, which are 57% and 3%, respectively. We discuss the implications to the AMP systems by comparing the efficiency upper limit values with that of 20 γ-ray millisecond pulsars (MSP) detected by Fermi and the newly discovered transitional MSP binary J1023+0038.
Primary author
Ms
Yi Xing
(yixing@shao.ac.cn)
