Black Holes: Gravity's Relentless Pull

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Black Holes: Gravity's Relentless Pull
OBJECT: 3C273 (Quasar)
DISTANCE: 2.5 billion lightyears
BLACK HOLE? Yes (supermassive)

This quasar in the constellation Virgo greatly puzzled astronomers when it was discovered, until they realized in the 1960s that it is a distant galaxy with a supermassive black hole in its center. The black hole is a billion times heavier than the Sun. It generates so much energy by consuming material that it outshines the rest of the galaxy a hundredfold. The name 'quasar' stands for quasi-stellar object, since that was astronomer's best description of this object at first. The name 3C273 identifies it as number 273 in the third Cambridge catalog of radio sources.

The visible light image of 3C273 shows bright light from near the black hole, as well as a wiggly jet. The latter consists of electrons propelled outwards by the energy generated near the black hole. The jet is seen even more clearly in the radio and X-ray images. 3C273 is a prototypical quasar, but it does have some unusual features. It shines brightly in radio waves, which is true for only ten percent of all quasars. And although such quasars often have jets, they rarely reveal themselves in visible light.

3C273 is one thousand times further away than the Andromeda galaxy, but most quasars are even further away. Their light has traveled so long to get to us that we see them when they were still young. Most galaxies that are now old, with a quiescent supermassive black hole in their center, probably passed through a phase of quasar activity in their youth.

X-Ray image of: 3C273 (Quasar)
The region just outside the black hole event horizon shines very bright in X-rays (colored yellow). The jet is seen as well.