X rays reveal black hole dining habits.From arsenic to zinc, black holes gobble up every element within their grasp. Even among such undiscriminating un·dis·crim·i·nat·ing adj. 1. Lacking sensitivity, taste, or judgment. 2. Indiscriminate. Adj. 1. undiscriminating - not discriminating indiscriminating diners, some have bigger appetites than others. Researchers report that for the first time they have found an indicator of how rapidly these gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. monsters devour their surroundings. The indicator consists of X rays emitted by iron atoms after they fall onto a swirling disk of matter around a black hole. This emission, first detected in the early 1990s in a group of nearby galaxies that are relatively dim but have bright centers, is shifted in wavelength by a strong gravitational field--a tip-off that these galaxies house black holes. In the new study, researchers used the sensitive ASCA ASCA American School Counselor Association ASCA Australian Shepherd Club of America ASCA Arab Society of Certified Accountants ASCA American Swimming Coaches Association ASCA American Society of Consulting Arborists ASCA Association of State Correctional Administrators satellite to study the same X-ray emission from 39 new sources, including 21 highly luminous, but distant, quasars. Quasars are thought to be powered by massive, central black holes. In the Oct. 20 Astrophysical Journal Letters, Paul Nandra and Richard F. Mushotzky of NASA's Goddard Space Flight Center The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately 6.5 miles northeast of Washington, D.C. in Greenbelt, Md., and their colleagues report a striking correlation: The X rays generated by iron atoms in quasars have a much lower intensity than those produced by iron atoms in less luminous galaxies. Indeed, in the most luminous quasars, the X-ray signal vanishes altogether. The astronomers suggest that iron atoms at the cores of the brightest galaxies and quasars are bombarded by a much higher dose of radiation than those in the less luminous galaxies. The intense bombardment strips the atoms of their electrons, the charged particles that generate the X rays. Therefore, the ionized i·on·ize tr. & intr.v. i·on·ized, i·on·iz·ing, i·on·iz·es To convert or be converted totally or partially into ions. i atoms do not emit X rays when they fall onto the disk of matter circling the central black hole. There are two reasons why some galaxies that house a black hole are brighter than others. Nandra notes. Either the black hole in the brighter galaxies is more massive, or it is feasting on matter at a higher rate. The second possibility is more likely, Nandra says. Theoretical calculations indicate that the most voracious black holes can most easily ionize i·on·ize v. To dissociate atoms or molecules into electrically charged atoms or radicals. i  on·iz atoms. "As black holes swallow material at a greater rate, the X-ray emissions become dimmer," he notes. The new report, says Christopher S. Reynolds of the University of Colorado University of Colorado may refer to:
If additional data corroborate To support or enhance the believability of a fact or assertion by the presentation of additional information that confirms the truthfulness of the item. The testimony of a witness is corroborated if subsequent evidence, such as a coroner's report or the testimony of other this interpretation, Reynolds says, it could prove a milestone for probing the twisted, Alice-in-Wonderland world around black holes. |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion