The Very Large Array Sky Survey (VLASS)

Mapping the Radio Universe

Most of the marvels of the universe are invisible to us without technological assistance. Visible light is only a small slice of the electromagnetic spectrum, ranging from tiny, high-energy gamma rays to long, slow-moving radio waves. Imagine if you could put on radio glasses to view a range of light obscured from all but the most sophisticated telescopes. What would you see? You might be able to peer through dusty clouds and view the beginning stages of star formation or watch intermittent lighthouse bursts from pulsars, if the neutron star happens to be pointing towards earth at the right angle. What would it be like to see an array of energetic particles dancing around the Sun’s corona?

On September 7, 2017, the Jansky Very Large Array (VLA) pointed its antennas toward the northern sky and began one of the largest all-sky radio observations in 40 years. The VLA Sky Survey (VLASS) will map 80 percent of the sky in 3 phases over 7 years and is expected to catalog approximately 10 million new radio sources. The survey will collect data from powerful, cosmic sources, producing data that will allow us to image supernovae explosions, gamma-ray bursts, and the collisions of neutron stars that are obscured from visible-light telescopes by thick clouds of dust. The VLA’s ability to see through dust and clouds will make the survey an important tool in the discovery of new radio objects.

Optical Sky Milky Way Galaxy

9/7/2017 - The beginning. Move through each slider to visualize the multilayered view of sky we'll be observing over 7 years.

Epoch 1.1 B September 13, 2017 - January 29, 2018

The first observation in configuration B. As the sky survey progresses and we collect more data, we'll be able to compare this view 3 times over!

Epoch 1.1 BnA February 02, 2018 - February 19, 2018

Hybrid Configuration BnA. The telescopes gather data from two different vantage points, allowing us to balance the quality of the total image.

Epoch 1.2 B January 23, 2019 - June 03, 2019

There are 3 epochs over 7 years. Within 1 epoch we collect data four different ways in order to cover 80 percent of the sky.

Epoch 1.2 BnA June 07, 2019 - June 24, 2019

End of 1st Epoch.

Epoch 2.1 B May 27, 2020 - October 05, 2020

Beginning of Epoch 2. We expect to discover powerful cosmic explosions, such as supernovae, gamma ray bursts, and the collisions of neutron star.

Epoch 2.1 BnA October 09, 2020 - October 26, 2020

Midway through our survey.

Epoch 2.2 B September 29, 2021 - February 14, 2022

Epoch 2.2 BnA February 18, 2022 - March 07, 2022

At this point in the survey, we've viewed 80 percent of the sky twice over.

Epoch 3.1 B February 01, 2023 - June 12, 2023

Beginning of Epoch 3.

Epoch 3.1 BnA June 16, 2023 - July 03, 2023

Hybrid Configuration

Epoch 3.2 B May 29, 2024 - October 07, 2024

Penultimate View

Epoch 3.2 BnA October 11, 2024 - October 28, 2024

THE END! Now, we have 3 complete, in-depth views over 80 percent of the sky. Data from all three observations will be combined to make sensitive radio images publicly available.

Discovery and the Practical Applications of Astronomy
Astronomy is a vital part of our everyday culture, and new discoveries about the universe have been communicated for centuries, enriching the lives of millions. From the dawn of civilization, astronomy has provided important stepping stones for human progress. Our calendar and system of timekeeping developed from astronomical observations. Much of today’s mathematics is the result of research done on the movement and angles of stars and planets. Trigonometry was invented by Hipparchus, a Greek astronomer. Astronomy also provided the navigational techniques that allowed sailors and aviators to explore our planet enabling todays spacecraft to explore our solar system. The space age, which brought us the communication and weather satellites upon which we depend each day, would have been impossible without the fundamental knowledge of gravity and orbits discovered by astronomers. Radio astronomers led the development of low-noise radio receivers that made possible the satellite communications industry.

VLASS Configurations

B Configuration

The antennas in the Very Large Array are used like the zoom lens in a camera. When they are in the B configuration, the telescopes extend over the 11 kilometers (7.08 mile) length of each arm. In this configuration, we have the second largest magnification and can see great detail. The size of the array gradually decreases with the C configurations until, in the D configuration, the telescopes are all placed within 0.6 kilometer (0.4 mile) of the center.

BnA Configuration

The BnA is a hybrid configuration. The north arm of the array is extended out into the A configuration location. This allows the VLA to image objects closer to the horizon.

The iconic “Y” shape of the VLA has a specific function. The wider an array, the bigger its eye is, and the more detail it can see out in space. The VLA’s unique shape gives us three long arms of nine telescopes each. It also gives our scientists the flexibility of stretching the arms when we need to zoom in for more detail. 

Check out these videos for more information on the different VLA configurations and the amazing machines that move the 230 ton antennas around.

Featured Sky Survey Image

The sharpest radio view ever made of such a large portion of the sky. A brand new galaxy has been discovered in radio wavelengths with the VLA Sky Survey! The galaxy, classified as 6C B191505.9+674609, resides near the constellation Draco in the northern hemisphere. No sources were detected in the optical (blue) or infrared (orange) images. The green, radio image depicts a faint source – we know something is there! Our very first VLASS image makes a new discovery.

VLASS Comparison