Two groups of researchers last week sought to deliver separate killer blows to a controversial theory about quasars. Instead, they seem to have simply stirred up the same old hornets' nest.
Conventional wisdom says that quasars are the extremely luminous cores of very distant galaxies. A quasar's distance is derived from the shift in its spectrum toward redder wavelengths, which is thought to be caused as the expansion of the universe carries the quasar away from the Earth. But a small group of prominent astronomers, including Margaret Burbidge of the University of California, San Diego (UCSD), and the late Fred Hoyle, believes that quasars are bits of star stuff ejected by quite nearby active galaxies and that at least part of their redshift has an intrinsic cause.
The evidence? Quasars are much more numerous around these nearby active galaxies, and often they seem to be connected to them by luminous bridges and filaments. Moreover, studies carried out in the 1990s indicate that the redshifts of these quasars cluster around certain periodic values. All this is impossible to explain in the conventional view of the expanding universe.
But now astronomers at the University of Nottingham in the U.K. report in the October Monthly Notices of the Royal Astronomical Society (MNRAS) that they can find no evidence for redshift periodicities in a much larger sample of purported quasar-galaxy pairs taken from the recently completed Two Degree Field (2dF) survey. “Our plot shows there's nothing there,” says team member Edward Hawkins. Meanwhile, the Space Telescope Science Institute (STScI) in Baltimore, Maryland, issued a Hubble photo last week of the galaxy-quasar pair NGC 4319 and Mrk 205. Almost 20 years ago, Halton Arp of the Max Planck Institute for Astrophysics in Garching, Germany, showed that these two objects appear to be linked by a luminous “bridge,” but the new picture shows no obvious connection.
The redshift doubters aren't buying the new data, however. Geoffrey Burbidge, Margaret Burbidge's husband and fellow UCSD astronomer, claims there's a statistical flaw in the new redshift. And Arp accuses STScI of "deliberately misleading the public.” This week his former student Jack Sulentic of the University of Alabama, Tuscaloosa, released an enhanced version of the same image, showing a bridge. Clearly, neither side has spoken its last words on the subject.