27 May 2015 STScI-2015-19

ABOUT THIS IMAGE：
[Left] In this NASA Hubble Space Telescope image of the central region of the galaxy NGC 3862, an extragalactic jet of material moving at nearly the speed of light can be seen at the three o'clock position. The jet of ejected plasma is powered by energy from a supermassive black hole at the center of the elliptical galaxy, which is located 260 million light-years away in the constellation of Leo.
[Right] A sequence of Hubble images of knots (outlined in red, green, and blue) shows them moving along the jet over a 20-year span of observing. Astronomers were surprised to discover that the central knot (green) caught up with and merged with the knot in front of it (blue). The new analysis suggests that shocks produced by collisions within the jet further accelerate particles that are confined to a narrowly focused beam of radiation. The "X" marks the location of the black hole.