Tracking the path of a black hole. (Astronomy).Astronomers have for the first time measured the motion of a small black hole and a companion star speeding through our galactic neighborhood. The black hole and the star that it's slowly devouring travel together on a looping path that ultimately will take them toward the outer reaches of our galaxy. In the Sept. 13 NATURE, researchers argue that the black hole, which is the compact remains of a massive star, was ejected from a star cluster star cluster, a group of stars near each other in space and resembling each other in certain characteristics that suggest a common origin for the group. Stars in the same cluster move at the same rate and in the same direction. . Ever since, it has been wandering the galaxy along with its stellar companion, the scientists propose. Known as XTE XTE X-Ray Timing Explorer XTE Cross Track Error J1118+480, the duo was discovered last year by NASA's Rossi X-ray Timing Explorer The Rossi X-ray Timing Explorer (RXTE) satellite observes the fast-moving, high-energy worlds of black holes, neutron stars, X-ray pulsars and bursts of X-rays that light up the sky and then disappear forever. satellite. Studies of its radio emissions reveal that the black hole-star combo qualifies as a miniature version of a quasar quasar (kwā`sär), one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects in the universe; the name is shortened from . Material snared by the black hole from its companion has formed a swirling disk around the hole. Jets of subatomic particles spew from the disk, emitting radio waves Radio waves Electromagnetic energy of the frequency range corresponding to that used in radio communications, usually 10,000 cycles per second to 300 billion cycles per second. . Quasars Proper naming of quasars are by Catalogue Entry, Qxxxx±yy using B1950 coordinates, or QSO Jxxxx±yyyy using J2000 coordinates. This page lists quasars.
Because of the pair's proximity to Earth, astronomers were able to track the motion of the black hole and its partner with the Very Large Baseline Array, a network of radio telescopes that stretches from Hawaii to the U.S. Virgin Islands. The duo zips through space at 145 kilometers a second, notes study coauthor I. Felix Mirabel, who is affiliated with both the Institute for Astronomy The Institute for Astronomy (IfA) is a research unit within the University of Hawaii system, led by Dr. Rolf-Peter Kudritzki as Director. IfA main headquarters are located at 2680 Woodlawn Drive in Honolulu, Hawaii; additional facilities are located at Kula, Maui and Hilo on the and Space Physics in Buenos Aires and the French Atomic Energy Commission Atomic Energy Commission (AEC), former U.S. government commission created by the Atomic Energy Act of 1946 and charged with the development and control of the U.S. atomic energy program following World War II. in Gif-sur-Yvette, France. The orbit of XTE J1118+480 resembles that of globular clusters, large groupings of the oldest stars in the galaxy. Unlike most stars in the Milky Way, globular clusters don't reside within the galaxy's plane. Instead, they orbit the Milky Way's center along paths that take them below and above the plane. The similar orbit of the black hole suggests that it long ago received a strong kick that expelled it from a globular cluster or from a region within the Milky Way's disk. Simulations of that event suggest that a globular cluster is the most likely source of the black hole. The massive star that collapsed to become the black hole "probably formed in a globular cluster even before our galaxy's disk was formed," Mirabel says. The observations therefore mark "the intense burst of star formation that took place during an early stage of our galaxy's development," he says. --R.C. |
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