July 22, 2012
Jansky Very Large Array Achieves First Light
redOrbit Staff & Wire Reports - Your Universe Online
Researchers with the U.S. Naval Research Laboratory (NRL) and the National Radio Astronomy Observatory (NRAO) in New Mexico announced Friday that they had successfully achieved "first light" at low frequencies using the Jansky Very Large Array (JVLA) radio astronomy telescope.
Using five of the JVLA's 27 230-ton, 25-meter diameter very high-frequency (VHF) dish antennas, NRAO astronomer Dr. Frazer Owen was able to map the radio sky at 337 MHz on May 1, the NRL announced in a July 20 statement. The first light image comes as a new, wide-band receiver system developed by scientists and engineers from both organizations and was being deployed on board the JVLA to extend its frequency range.
This initial demonstration of the telescope's interferometric imaging capabilities was called "a key milestone" by NRL officials, who added that it was "strong verification that the new receivers have the sensitivity, stability, and coherence critical to the needs of the international radio and space science communities, with key benefits for both astronomical and ionospheric science applications."
"The use of over 100 megahertz of bandwidth in the first image is a dramatic illustration of the breakthrough to instantaneous wideband systems at frequencies below one gigahertz," said Dr. Namir Kassim, section head of the NRL Radio Astrophysics Section. "This represents a poorly explored part of the electromagnetic spectrum that is important for ionospheric and astrophysical research and to the Navy's mission for navigation and communications."
The telescope is not currently at full strength, according to the Navy. A 2011 upgrade to the receivers made it so the JVLA was unable to operate at VHF capabilities between 30 MHz and 300 MHz, and only five of the observatory's telescopes have been outfitted with the new receivers. All 27 should be fully equipped by next summer, however, and the "first light" image has been called a "critical" step in that direction.
"The loss of low-frequency capability to the world's most powerful radio telescope was a set-back not only to the radio research community, but to continued astrophysics and ionospheric work critical to the needs of Navy communications and navigation," NRL radio astronomer Dr. Tracy Clarke said.
"With the new greatly improved receivers and the demonstration that they work well with the JVLA, scientists are once again able to explore with greater veracity the low-frequency radio bands for high sensitivity astrophysics and high accuracy ionospheric research," Clarke added.
According to the NRL, the JVLA is considered to be the largest and most capable radio telescope array on Earth. It is funded by the National Science Foundation (NSF) and Associated Universities, Inc. (AUI), and the collaboration between the NRL and the NRAO on the project dates back to the 1980s, when the two organizations first joined forced to develop a 330 MHz Very Large Array system that has been used in astrophysics and ionospheric sciences over the course of many years, the Navy press release noted.