Hercules A

Hercules AHercules A, also known as 3C 348, lies around two billion light-years away. It is one of the brightest sources of radio emission outside our Galaxy. It’s the bright object at the middle of the frame, an elliptical galaxy. As seen in visible light by the Hubble Space Telescope it appears floating serenely in the inky blackness of space, but adding data from a radio telescope radically transforms the image. Jets of material can be seen billowing outwards from the galaxy when viewed at radio frequencies—jets that are completely undetectable in visible light. The image above combines data from the Very Large Array radio observatory in New Mexico with data from Hubble‘s Wide Field Camera 3.

The two jets are composed of hot, high-energy plasma that has been flung from Hercules A by a supermassive black hole lurking at the galaxy’s core. This black hole is roughly 2.5 billion times the mass of the Sun. That’s about a thousand times more massive than the black hole at the centre of the Milky Way.

Hercules A’s black hole accelerates the ejected material to nearly the speed of light, sending it flying out into intergalactic space. Eventually, the highly focused jets lose energy, slowing down and spreading out to form cloud-like blobs The multiple bright rings and knots seen within these blobs suggest that the black hole has sent out successive bursts of material. The jets stretch for around 1.5 million light-years, around 15 times the size of the Milky Way.

Image Credit: NASA / ESA / VLA


Hercules A

Hercules A is the brightest radio source in the constellation of Hercules. Astronomers found that the double-peaked radio emission was centered on a giant elliptical galaxy known as 3C 348. This galaxy is not found within a large cluster of hundreds of galaxies, but rather within a comparatively small group of dozens of galaxies. The active part of the galaxy is the supermassive black hole in its core, sending out strong jets of energetic particles that produce enormous lobes of radio emission. It’s been suggested that Hercules A may be the result of two galaxies merging together.

This video imagines a three-dimensional look at the combined visible light (Hubble Space Telescope) and radio emission (Very Large Array) from Hercules A. The radio lobes dwarf the large galaxy and extends throughout the volume of the surrounding galaxy group. This visualization is only a scientifically reasonable guess of the three-dimensional structures. For example, the galaxy distances within the group are based on a statistical model, and not measured values.

Video Credit: NASA

Hercules A, Cosmic Bow Tie

herca_vlahstNo one is sure why Hercules A, the galaxy at the center of this picture is throwing of such huge jets of material, but it is likely related to an active supermassive black hole at its center. The galaxy appears to be a relatively normal elliptical galaxy in visible light. When observed by a radio telescope, however, tremendous plasma jets over one million light years long are visible. Analysis indicates that the central galaxy (aka 3C 348) is actually over 1,000 times more massive than our Milky Way Galaxy, and its central black hole is nearly 1,000 times more massive than the black hole at our Milky Way. This image was assembled by superimposing data from the Very Large Array (VLA) of radio telescopes in New Mexico with an optical image from the Hubble Space Telescope. The best guess for the energy source for the jets is matter swirling toward the galaxy’s central black hole.

Image Credit: NASA