Highlights of Current VLA
1-31 January 2008
Tuesday, 20-Jan-2009 10:13:47 MST
Studying a Giant Hole in the Universe
Last summer, astronomers
announced that, using data from
the VLA, they had discovered a huge void, or "hole," in
the Universe, nearly a billion light-years across and
containing almost no matter. This month, they are making
detailed observations of this region to confirm the finding
and refine their determination of the void's distance from
Earth. Continued study of this huge void will help scientists
understand the evolution of large-scale structure in the
Universe and the nature of the mysterious "dark energy"
that appears to be accelerating the expansion of the
Star Formation and Gas in Nearby Galaxies
Scientists who earlier
used the Hubble Space Telescope
(HST) to study a number of nearby galaxies in great
detail now are using the VLA to study the distribution
of hydrogen gas in those same galaxies. The VLA images
of the gas in the galaxies will show about the same level
of detail seen in the HST visible-light images. The
combination of visible-light and radio images will
allow the astronomers to better understand how star
formation is triggered in the galaxies and how the
outflows from young stars interact with the thin gas
that pervades the galaxies.
Gamma Ray Bursts
The VLA will be used by
astronomers looking for radio
emission from the "fireballs" presumed to result from
the explosions that cause cosmic bursts of Gamma rays.
This month, they are monitoring the fireball of a burst
detected on January 25, and still visible to the VLA.
In May 1997, the VLA made the first-ever detection of
radio waves coming from a Gamma Ray Burster, and measured
the emission from that object for months afterward. As
satellites with gamma-ray detectors continue to give
rapid notice of these bursts, the VLA, along with other
ground-based observatories, will seek to detect the
objects at wavelengths longer than those of gamma rays.
The VLA also has detected radio emission from many
other Gamma Ray Bursters since then.