A galaxy that goes the distance?Aided by a cosmic magnifying glass magnifying glass: see microscope. magnifying glass traditional detective equipment; from its use by Sherlock Holmes. [Br. Lit.: Payton, 473] See : Sleuthing , astronomers may have found a baby picture of the most distant galaxy known. Its faint spectra suggest that it lies about 13.2 billion light-years from Earth, exceeding the current record holder by about 300 million light-years (SN: 3/30/02, p. 1963. If that's true, the galaxy would hail from a time when the universe was a mere 470 million years old. To find the galaxy, Daniel Schaerer of the Geneva Geneva, canton and city, Switzerland Geneva (jənē`və), Fr. Genève, canton (1990 pop. 373,019), 109 sq mi (282 sq km), SW Switzerland, surrounding the southwest tip of the Lake of Geneva. Observatory in Sauverny, Switzerland, and his colleagues examined the central region of a relatively nearby cluster of galaxies cluster of galaxies Gravitationally bound grouping of galaxies, numbering from the hundreds to the tens of thousands. Large clusters of galaxies often exhibit extensive X-ray emission from intergalactic gas heated to tens of millions of degrees. , Abell 1835. The cluster's enormous mass acts as a gravitational lens gravitational lens n. A massive celestial object, such as a galaxy, whose gravity bends and focuses the light of a more distant object, resulting in a magnified, distorted, or multiple image of the original light source for a distant observer. , magnifying, brightening, and distorting images of more-distant galaxies. The astronomers used an infrared detector An infrared detector is a photodetector that reacts to infrared (IR) radiation. The two main types of detectors are thermal and photonic. The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena. on the European Southern Observatory's Very Large Tele scope in Paranal, Chile. Comparing images of the same region taken with two other telescopes, the researchers verified that the newly identified galaxy, dubbed Abel11835IR1916, shows up in near-infrared images but not in visible light--an indication that the galaxy is extremely distant. Infrared-spectra reveal a specific wavelength that appears to represent the ultraviolet glow of hydrogen atoms, the researchers report in an upcoming Astronomy & Astrophysics astrophysics, application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. . The team posits that the gas' ultraviolet radiation has been shifted to a longer, near-infrared wavelength by the galaxy's great distance. Other astronomers have their doubts. Richard G. McMahon of the University of Cambridge in England says that hydrogen may not be the origin of the near-infrared wavelength observed by the team. That could undermine the argument for the galaxy residing so far from Earth. |
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