Title: The black-widow pulsar systems unveiled by gamma-ray and multi-wavelength observations

Speaker: Dr. Thomas Tam (National Tsinghua University, Taiwan)

Time: 10 am, Aug. 20 (Tuesday), 2013

Location: middle conference room (3rd floor)

Abstract:

The Fermi Large Area Telescope (LAT) has revealed a number of millisecond pulsars (MSPs) in our Galaxy. They are important contributors to gamma-ray point sources outside the Galactic plane sky region. While some gamma-ray MSPs are isolated, others are in binary systems; many show evidence of ablating their very low to low mass companions, joining the so-called 'black widow (BW)' pulsar population. In some cases radio/BW MSPs are found in the error box of unassociated Fermi objects ('UFOs') through multi-wavelength (radio, optical, and X-rays) observations. The BW system, 2FGL J2339.6-0532 is a notable example of such kind of dedicated studies. In one single case, gamma-ray emission is discovered from the direction of a BW system (PSR J1023+0038), which is undergoing a transition from an accretion disk-powered to a rotation-powered MSP. Towards he end of my talk, I will also highlight the case of a bright gamma-ray burst occurred on April 27, 2013.