Seyfert galaxies are spiral galaxies with very bright nuclei and spectra that are often reminiscent of quasars, although the nuclei of Seyferts are not as bright as quasars. They were first described by Carl Seyfert in 1943. As in the case of quasars, astronomers believe there may be a supermassive black hole at the tenter of a Seyfert galaxy nucleus.
In this image of the central region of the Seyfert galaxy Markarian 315, the brighter of the two bright spots is the nucleus of the galaxy. The smaller spot was discovered in the HST observations. It is separated from the nucleus by about two arc seconds on the sky, equivalent to a real distance of about 6,000 light years. The smaller spot may represent the central core of a now-vanished galaxy that collided with Markarian 315 and was swallowed up by it.
Wider-angle observations of Markarian 315 obtained with telescopes on the ground show a plume of gas about 240,000 light years long. The plume may be a 'tidal tail', ripped out of the colliding galaxies as they merged. Other gas disturbed by the collision may be falling toward the suspected black hole in the nucleus of Markarian 315, being heated by friction as it does so and thereby making the nuclear region shine brightly.
Camera: WF/PC-1
Technical Information: Image shown in
false color.
Credit: J. MacKenty (STScI), and NASA
