主 讲 人：李剑 博士后、洪堡学者
Microquasars, the local siblings of extragalactic quasars,are binary systems comprising a black hole of several to tens of solar massesand a companion star. By accreting matter from their companions, microquasarslaunch powerful winds and jets, influencing the interstellar environment aroundthem. Steady gamma-ray emission is expected to rise from their central objects,or from interactions between their outflows and the surrounding medium. Thelatter prediction was recently confirmed with the detection at the highest(TeV) energies of SS 433, one of the most interesting microquasars known. Weanalyzed more than ten years of GeV gamma-ray data on SS 433. Detailed scrutinyof the data reveal emission associated with a terminal lobe of one of the jetsand with another position in the SS 433 vicinity, co-spatial with a gasenhancement. Both gamma-ray sources are relatively far from the central binary,and the latter shows evidence for a periodic variation at the precessionalperiod of SS 433, linking it with the microquasar. This result challengesobvious interpretations and is unexpected from any previously publishedtheoretical models. It provides us with a chance to unveil the particletransport from SS 433 and to probe the structure of the local magnetic field inits vicinity.
Dr. Jian Li pursued his Ph.D. jointly atInstitute of High Energy Physics, China and Institute of Space Sciences, Spain.Currently he is a Humboldt Fellow at the Deutsches Elektronen-Synchrotron DESY,Germany. Dr. Jian Li's research is mainly aimed at understanding particleacceleration process and high energy emission mechanism in Galactic sources, ina multi-wavelength context. Dr. Jian Li's research topics cover binaries,pulsars and their related nebulae, supernova remnants, and other Galacticcompact objects.