US SKIES are clearer than usual after the in June from analogue to digital TV freed up a chunk of the radio spectrum. Astronomers are now rushing to see what they can find before transmissions from cellphone companies and others fill the space.
Prior to the switch-over, naturally occurring radio waves at frequencies between 700 and 800 megahertz were obscured by analogue TV signals, preventing astronomers from investigating the universe using this band. Now a receiver has been installed at the in Puerto Rico to take advantage of the new-found clarity.
The window is giving astronomers their first radio views of galaxies that thrived when the universe was about half its present age. They hope to measure how much hydrogen 鈥� the raw material for new stars 鈥� the galaxies had. 鈥淚t鈥檚 a once-in-a-lifetime opportunity to see galaxies in that range,鈥� says Arecibo researcher . 鈥淲e鈥檙e able to see an epoch that hasn鈥檛 been observed before with radio eyes.鈥�
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鈥淭he freeing up of this bandwidth is a once-in-a-lifetime opportunity to see galaxies in this range鈥�
The new window may also help in the hunt for pulsars 鈥� neutron stars that emit beams of radio waves from their poles. In this part of the spectrum, their beams are less impeded by interstellar electrons, which can scatter radio waves.
This boosts the chances of spotting rare examples of these stars. 鈥淲e鈥檙e looking for pulsar exotica,鈥� says of West Virginia University in Morgantown. He and colleague Mitch Mickaliger are hoping to find a pulsar orbiting a black hole, an as-yet-undiscovered pairing that could be used to test general relativity.
This radio window won鈥檛 be open for long, though. Much of the new band has already been auctioned off, and astronomers at Arecibo might only get a year of clear skies, says of Cornell University in Ithaca, New York.
