Angular size of box = 40 arcsec, corresponding to 900,000 light years
Photo: NASA/CXC/SAO

The X-ray image of 3C295 shows an explosive galaxy embedded in a vast cloud of hot gas. This cloud, which contains over a hundred galaxies, is more than two million light years in diameter and has a temperature of fifty million degrees. The X-rays from the central galaxy are concentrated in three bright knots that form a line. The central knot coincides with the center of the galaxy; these X rays are probably produced by matter falling into a supermassive black hole. The upper and lower knots are in the same location as two large lobes of radio emission. The distance from the top to the bottom knot is about 100,000 light years, comparable to the diameter of our Milky Way galaxy.

scale bar = 2 arcsec, corresponding to 40,000 light years
Photo: NASA/HST/A.Dressler

In the optical image 3C295 appears as a giant elliptical galaxy that is twice as luminous as our Milky Way galaxy. The galaxy extends beyond the X-ray and radio lobes. The center, or nucleus of the galaxy is not nearly as prominent as in X rays, although optical observations do provide evidence for a large amount of gas at temperatures of about 10,000 degrees, which is apparently heated by ultraviolet and X radiation from the nucleus.

Angular size of box = 8 arcsec, corresponding to 180,000 light years.
Photo: NRAO/VLS/R. Perley & G. Taylor

The radio image shows many similarities to the X-ray image: two lobes on either side of the nucleus. The lobes have bright spots where the radiation is especially intense. The radio lobes are produced by the synchrotron process, where high-energy electrons move through a magnetic field and radiate radio waves. If the energies of the electrons are high enough, this process can also produce optical and X radiation. Study of the radio lobes indicates that they were blasted out at high speeds from the supermassive black hole in the nucleus less than a million years ago.

Revised: May 17, 2022