September 22, 2010

New Telescope To Look For Universe’s First Stars

Britain has officially opened the first station in a new global radio astronomy antenna network.  Dubbed LOFAR (Low Frequency Array), the European project will employ new digital techniques to simultaneously survey large portions of space.

The new station in Britain joins similar installations in Sweden, France, Germany and the Netherlands. Scientists hope the new network will enable them to explore the formation of the very first stars in the universe.

"In traditional arrays, you have to move their dishes physically if they want to look in a different direction," said LOFAR project manager Derek McKay-Bukowski during an interview with BBC News.

"LOFAR is a digital telescope which means you can switch the direction where you're looking very fast. You can go from one side of the sky to the other side of the sky - rather than in minutes, you can do it milliseconds. And because it's digital, LOFAR can look in multiple directions at once," he said.

Additionally, the telescope is sensitive to radiation of longer wavelengths than Britain's existing Merlin radio telescope array.

The ability to detect that particular part of the electromagnetic spectrum (1-10m/240-30MHz) will allow scientists to study new astrophysical phenomena.  Specifically, astronomers are interested in the period of re-ionization, during which the formation of the very first stars in the universe created a vital change in the cosmic environment.

Researchers believe these enormous young stars produced intense ultraviolet radiation that "fried" the neutral gas that had formed up to that point -- something that can be detected today as a diffuse plasma between the galaxies.

Experts say seeing these initial stars is simply beyond the capability of existing telescopes like Hubble or the VLT.  However, conditions during this time period could be explored at LOFAR frequencies.

Scientists plan to install additional antennas in the years ahead to make LOFAR ever more sensitive.

"When the entire project is finished, we will have something in the order of 5,000 antennas for both low-band and high-band, which will be located at about 48 stations across Europe," said McKay-Bukowski.

"The biggest separation is about 1,100km. Distance between stations gives you resolution; to see finer detail you need bigger and bigger separations."

The LOFAR system operates at the lowest frequencies accessible from Earth.  The signals received by LOFAR are then sent via fiber optic cables to a central IBM supercomputer, which combines all the data to make a synthetic radio image of exceptional quality.

In addition to exploring the re-ionization period, the LOFAR initiative has five other primary research areas.  These include:

1. Exploring space outside our galaxy to better understand the history of star formation and the growth of black holes.

2. Surveying the extreme space conditions that lead to transient bright bursts.

3. Understanding cosmic rays, the storm of high-energy particles that impact the Earth.

4. Investigating the local space environment to understand how the wind of particles moving away from the Sun interacts with the Earth.

5. Studying the origin of the large-scale fields that saturate the universe.


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