Lyman-alpha emitter

A lyman-alpha emitter is a type of object in space that gives off a special type of light called the Lyman-alpha line.

Now, imagine you're drawing with a colored pencil. Let's say you have a blue pencil, and you're drawing a picture of the sky. When you draw with a blue pencil, you're making blue marks, which makes your picture look blue overall.

In a similar way, when objects in space give off different types of light, they look different colors overall. The Lyman-alpha line is a type of light that looks like a bright, reddish-pink color.

So, when we say a lyman-alpha emitter is "emitting" something, we mean that it's giving off this bright, reddish-pink light.

Scientists are really interested in these lyman-alpha emitters because they can tell us a lot about what's going on in space. When they study these objects, they can learn things like how stars and galaxies form, how they behave, and even how they interact with each other.

So, to sum it up: a lyman-alpha emitter is a type of thing in space that gives off a very special type of light called the Lyman-alpha line, and scientists study them to learn more about what's happening out in the universe.