Y. X. Yap (National Tsing Hua University, Institute of Astronomy and Department of Physics); K.L. Li (Michigan State University, Department of Physics and Astronomy);A. K. H. Kong (National Tsing Hua University, Institute of Astronomy and Department of Physics)
We present our recent optical observations of the redback millisecond pulsar PSR J1048+2339. This compact binary pulsar system was discovered by a radio pulsation search of a previously unidentified gamma-ray source, and was found to have an orbital period of 6 hours and a spin period of 4.66 ms. Using the radio timing position, an optical counterpart was identified. Previous sparse sampling optical observations suggest that the companion is a late-type star with a minimum mass of 0.3 solar-mass. By using the Lulin 1m Telescope and the 2m Liverpool Telescope, we obtained multi-colour light curves of PSR J1048+2339 with good sampling and resolution. The system clearly shows a 6-hr orbital modulation, which is likely caused by pulsar heating as well as ellipsoidal variation. We will present our preliminary results including light curve modelling for extracting the system properties.