Astronomers find overheated early universe using new capabilities of Hubble telescope

[News_Editor]

Astronomers find overheated early universe using new capabilities of Hubble telescope

2010-10-08 07:22:26 GMT+7 (ICT)

WASHINGTON D.C. (BNO NEWS) – A team of astronomers on Thursday announced that an investigation made with the new capabilities of the Hubble Telescope resulted in the uncovering of an overheated early universe, around 11 billion years ago.

Using the National Aeronautics and Space Administration's (NASA) space telescope, the astronomers found that during a period of universal warming, quasars produced fierce radiation blasts that stunted the growth of some dwarf galaxies for 500 million years.

Quasars are the brilliant core of active galaxies. The period took place from 11.7 to 11.3 billion years ago. In that time, ultraviolet light emitted by active galaxies stripped electrons off helium atoms. Such process known as ionization heated intergalactic helium from 18,000 degrees Fahrenheit to 40,000 degrees.

As a result, gas was inhibited from gravitationally collapsing to form new generation of stars in some small galaxies. The discovery was possible through Hubble's Cosmic Origins Spectrograph (COS) due to its improved sensitivity and lower background noise compared to other spectrographs in space.

The universe went through an initial heat wave more than 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen caused by the big bang, called reionization. The hydrogen nuclei were originally in an ionized state after the big bang.

The astronomers determined that it would take another two billion years before the universe produces sources of ultraviolet radiation with enough energy to reionize the primordial helium that was cooked up in the big bang. Such radiation came from supermassive black holes.

The helium's reionization took place during a transition phase when galaxies collided to ignite quasars. After the helium was reionized, intergalactic gas again cooled down and dwarf galaxies resumed normal assembly. If this had not occurred, more dwarf galaxies may have formed.

The astronomers said that there is only one perspective to measure the helium transition to its ionized state. The COS science team plans to use Hubble to look in other directions to determine if helium reionization uniformly took place across the universe.

-- © BNO News All rights reserved 2010-10-08