Abstract
Five years of observations with the Fermi Gamma-ray Space Telescope have revolutionized our knowledge of the gamma-ray pulsar population, leading to the discovery of over 40 millisecond pulsars (MSPs) by combining with deep radio observations. With this growing number of gamma-ray emitting MSPs and by combining multi-wavelength observing facilities, it is now possible to study their properties as a population. One of the successes is the discovery of radio-quiet gamma-ray MSP candidates and this opens a new window to study pulsars. Although radio-quiet gamma-ray MSPs are predicted by theories, they are observationally challenging and have never been detected. By combining X-ray and optical data, we have discovered the first candidate 2FGL J2339.6-0532 as a black widow-type MSP. In this presentation, we will present our new XMM-Newton, Suzaku, and JVLA follow-up observations of 2FGL J2339.6-0532. In particular, we will present the first millisecond pulsation search in the X-ray band and a detailed binary phase resolved X-ray spectroscopic study. We will also report preliminary results of a multi-wavelength search for other similar systems.