(for the HAWC Collaboration)
Particle acceleration in relativistic jets of astrophysical sources, such as AGNs and microquasars, is theoretically well-motivated, but direct evidence of acceleration site and composition of jets has not been observed above a few TeV. The HAWC collaboration recently reported TeV gamma-ray emission from SS433, one of the most powerful microquasars in the galaxy, which contains a supergiant star that is accreting matter onto a compact object. Previous observations of microquasars at lower energies have only seen emission from the central engine, however, HAWC observes TeV emission coincident with the lobes of the jets, suggesting particles are accelerated in the termination shocks of jets. Observations on TeV gamma-ray emission is valuable for studying particle acceleration in jets of microquasars, which also sheds light on jet physics in much larger and more powerful extragalactic jets in AGNs.