Astronomers Capture Radio Galaxy Hercules A

Astronomers using the Wide Field Camera 3 aboard NASA’s Hubble Space Telescope and the Karl G. Jansky Very Large Array radio telescope in New Mexico have produced a spectacular new image of a galaxy called Hercules A.

Hercules A, also known as 3C 348, is a bright and large radio galaxy located about 2 billion light-years away in the constellation of Hercules.

Emitting nearly a billion times more power in radio wavelengths than our Sun, the galaxy is one of the brightest extragalactic radio sources in the entire sky.

The galaxy is roughly 1,000 times more massive than our Milky Way Galaxy and harbors a 2.5-billion-solar-mass central black hole that is 1,000 times more massive than the black hole in our galaxy.

New radio data obtained with the VLA reveal enormous, optically invisible jets that, at one-and-a-half million light-years wide, dwarf the visible galaxy from which they emerge. The jets are very-high-energy plasma beams, subatomic particles and magnetic fields shot at nearly the speed of light from the vicinity of the black hole. The outer portions of both jets show unusual ring-like structures suggesting a history of multiple outbursts from the Hercules A’s super massive black hole.

The innermost parts of the jets are not visible because of the extreme velocity of the material, which causes relativistic effects that beam the light away from us. Far from the galaxy, the jets become unstable and break up into the rings and wisps.

The image also shows a companion elliptical galaxy very close to the center of the optical-radio source, which may be merging with the central galaxy. Several other elliptical and spiral galaxies that are visible in the Hubble data may be members of a cluster of galaxies.