London, Nov 15: Cosmologists have said that data from a satellite probing the early universe is not flawed, despite one radio astronomer's claim that it is hopelessly contaminated by radiation from our own galaxy.

The Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been investigating the afterglow of the Big Bang, called the cosmic microwave background (CMB).

This radiation is extremely uniform in brightness in all directions in the sky, but the WMAP has charted tiny variations between different parts of the sky to produce a map of the radiation.

Researchers have analysed the variations in detail and used them to calculate key properties of the universe.

Gerrit Verschuur of the University of Memphis in Tennessee, a veteran radio astronomer, has said that the variations in microwave radiation were actually caused by material in the Milkyway, so they don't reveal anything about the early universe.

He noticed alignments between the bright patches seen by WMAP and the distribution of hydrogen in our own galaxy.

The astronomer also pointed out that there were dozens of cases where bright patches in the WMAP data were closely aligned with concentrations of hydrogen in earth's galaxy.

He, however, does not dispute that the majority of the radiation came from the early universe, but adds that small amounts of additional radiation emanating from the Milkyway are causing changes in uniformity.

Cosmologists Kate Land of the University of Oxford, UK, and Ane Slosar of the Berkeley Center for Cosmological Physics in California, US, have countered Verschuur's claim by saying they have found no statistically significant connection between the two.

"If the correlation he claims is true, then this would be major news, " Slosar said.

"I would be surprised if such a big effect which Verschuur claims would escape the WMAP team anyway, but nevertheless, it is worth testing. What we found is what is expected, that there is no correlation between these two maps, " Slosar said.

Slosar added that their team tried filtering the hydrogen data in their study and still found only the small number of alignments expected by chance, rather than a larger, statistically significant number.

Verschuur hopes that young astronomers will take his claim seriously and further his investigations.

The study will be posted online in the Astrophysical Journal. (ANI)