Exploring The Universe With The Most Powerful Telescope on

Earth

Jim UlvestadNational Radio Astronomy Observatory

July 24, 2002

The Very Large Array (VLA)

Very Long Baseline Array (VLBA)

• 1993 dedication• Operated from

Socorro• 10 25-m

antennas• Highest

resolution imager in astronomy– sub-milliarcsec

Robert C. Byrd Green Bank Telescope

• 2000 dedication• Operated from

West Virginia• 100 x 110m,

novel offset design

• Just coming into full operation

Atacama Large Millimeter Array

• Joint project of North America and Europe

• 64 12m antennas• Will operate up

to 850 GHz (0.35 mm wavelength)

• At 5000 meters (16,500 feet) elevation

Green Bank Interferometer

Starting the VLADirt, Dirt, and More Dirt

Dedication Ceremony: 1980

The Long VLA Railroad System

Traffic Jam, VLA Style

VLA Synthesized Aperture• Synthesized

aperture in a few minutes, as “seen” by the radio source

• Composed of 351 pairs of antennas

Synthesized Aperture—1 hour• Synthesized

aperture after 1 hr of Earth rotation

• Each pair “fills in” more of the aperture

Synthesized Aperture—10 hours• Synthesized

aperture after 10 hrs of Earth rotation

• Aperture is “filled in”

• Very high fidelity imaging

Radio Galaxy Cygnus A: Pre-VLA

Cygnus A Imaged by the VLA

• Cosmic jets are ubiquitous

• They range from extragalactic jets to microquasars in our Galaxy

• Central black hole masses range from 1 to billions of solar masses

• Neutral hydrogen in tidal tails from merging galaxies

• This pair is the “Antennae,” NGC 4038/9

• Antennae interaction region, optical HST image with CO contours overlaid

• VLA 6cm image of Antennae interaction region shows the most recent star formation

Gravitational Lenses

The first Einstein ring, discovered by the VLA

An intervening galaxy “lenses” a background quasar into a ring

Cataclysmic Explosions in Distant Galaxies

Center of our Galaxy

Betelgeuse (" Orionis)

Red supergiant in Orion

Star contains a very bright radio-emitting corona

Caused by convection and mass loss in star’s atmosphere

Mercury: A Hot Planet with Ice

Radar transmitted by NASA tracking station is reflected and received by VLA

Red dot at top is water ice in shaded crater at North Pole

VLA is U.S. Taxpayer-Supported

Public and School Tours

The Expanded VLA (EVLA)

More than 700 astronomers use the VLA every year …However, most of the electronic equipment dates back to the

late 1970s

The VLA has produced more published science than any other telescope on the face of the EarthHowever, its capabilities have improved only incrementally

over the last 20 years

The Expanded VLA will keep the instrument at the forefront for another 20+ years

VLA: The Adventure Continues