Places along the way - Part 2

As we were driving across New Mexico toward Socorro, I had noticed something called "Very Large Array" on the map. Way back at the end of December, someone at the campground with us in Deming, NM, recommended that we visit that. We started seeing the dishes many miles away as we came into the San Agustin valley. We decided to go ahead and see it at that time instead of trying to drive back.

The antenna are spread across a wide area:

This is about 1/3 of them - from the center of the Y out one limb

 Each antenna is HUGE:

That's Dwayne just under the left side of the antenna.

It was really really windy yesterday, but fascinating to see. The visitors center has a neat video about what is accomplished with the VLA (collecting radio waves of space objects - can give a different point of view about stars and other light producing items in space than optical telescopes). It is generally used in conjunction with other optical telescopes (like those at McDonald Observatory in Texas, or on the big island of Hawaii, or the Hubble Space Telescope). I think they said that because radio waves are much longer, the total collection area needs to be much bigger - there are 27 active antennas placed in a Y pattern. The most interesting thing to me is that the antennas are not fixed in place - there are 4 different configurations, called A, B, C, and D. Each of the configurations presents a different view.

Information from the display:
 Each of the VLA dishes is actually larger than the biggest optical telescope in the world. However, a single VLA antenna cannot see as clearly as its optical cousin.

Why is that? Bigger telescopes do reveal finer detail, what astronomers refer to as having greater "resolving power". But radio waves are much longer than light waves, so a much bigger telescope is needed to resolve finer details.

How big? A radio telescope needs to be many miles across to rival the resolving power of an optical telescope. We can't build one dish that big, but the connected array of 27 large antennas of the VLA creat a telescope that is 22 miles in diameter!

Configuration D: 0.6 miles across

 This view is not sharp, but it shows us huge funnels of gas on either side of this galaxy. Where did they come from?

Configuration C: 2 miles across

 Now, we learn that these lobes are fed by strong jets coming from the central galaxy itself.

Configuration B: 7 miles across

 Although blurry, we start to see knots and bubbles in the jets. What could cause them?

Configuration A: 22 miles across

 At our highest resolution, we spot very stringy and lumpy features of these huge jets -- the signature burps of an active supermassive black hole!

The combined image of configurations A, B, C, and D

Our array of 27 radio antennas spans a huge "Y" shape (called the Wye). Every four months, we move antennas to different stations along each arm of the Wye. At its most compact configuration, the array has a wider field of view and maximum sensitivity to diffuse gas. At its most extended, we zoom in on finer detail. For complex objects, such as the huge, knotty jets of gas shooting out of radio galaxy Hercules A, we combine perspectives to build a complete picture.

To move the antenna, they have a railroad system and a neat car that can be made to go at right angles by raising the wheels and putting them onto perpendicular tracks:

It was super that we got to visit the Very Large Array!