From the Hubble Space Telscope
Streaming out from the center of the galaxy M87 is a black-hole-powered jet of electrons and other sub-atomic particles traveling at nearly the speed of light. In this NASA Hubble Space Telescope image, the blue of the jet contrasts with the yellow glow from the combined light of billions of unseen stars and the yellow, point-like globular clusters that make up this galaxy.
At first glance, M87 (NGC 4486) appears to be an ordinary giant elliptical galaxy; one of many ellipticals in the nearby Virgo cluster of galaxies. However, as early as 1918, astronomer H.D. Curtis noted a "curious straight ray" protruding from M87. In the 1950s when the field of radio was blossoming, one of the brightest radio sources in the sky, Virgo A, was discovered to be associated with M87 and its jet. The source of this incredible amount of energy powering the jet is a supermassive black hole at the center of M87, with a mass equivalent to 2 billion solar masses. The jet originates in the disk of superheated gas swirling around this black hole and is propelled and concentrated by the intense, twisted magnetic fields trapped within this plasma. The light that we see (and the radio emission) is produced by electrons twisting along magnetic field lines in the jet, a process known as synchrotron radiation, which gives the jet its bluish tint.
M87 has one of the nearest and is the most well-studied extragalactic jet, but many others exist. Wherever a massive black hole is feeding on a particularly rich diet of disrupted stars, gas, and dust, the conditions are right for the formation of a jet. Interestingly, a similar phenomenon occurs around young stars, though at much smaller scales and energies.
At a distance of 50 million light-years, M87 is too distant for Hubble to discern individual stars. The dozens of star-like points swarming about M87 are, instead, themselves clusters of hundreds of thousands of stars each. An estimated 15,000 globular clusters formed very early in the history of this galaxy and are older than the second generation of stars, which huddle closer to the center of the galaxy.
The data were collected with Hubble's Wide Field Planetary Camera 2 in 1998 by J.A. Biretta, W.B. Sparks, F.D. Macchetto, and E.S. Perlman (STScI). The Hubble Heritage team combined these exposures of ultraviolet, blue, green, and infrared light in order to create this color image.
Image Title: A Cosmic Searchlight
based on press release for PHOTO NO.: STScI-PRC0020
Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Last Modified On: Friday, December 15, 2000