Education Activities To Accompany Chandra Data Analysis Software M31 & Coma
Big, Bigger, Biggest
Activity 3: A look at the Coma cluster of galaxies in X-ray and visible light
A) Connect to the Chandra-Ed Archive server via the virtual observatory. Load the Coma image; select "sqrt" for the scale and "b" for the color. This will give you a good look at the X-ray emission as seen from the Chandra satellite. Notice that there is a diffuse elliptically shaped emission region as well as some point-like sources in the field of view. What you are seeing here is only the central (bright) portion of
the cluster.
B) To compare this to the visible light, we do the same thing we did for M31 above. Go
to: Frame > tiles frames; Analysis > DSS server > retrieve. What you see in the new, right hand frame are hundreds of galaxies. There are some stars (from our own Milky Way) as well, but all those slightly elongated elliptical blobs are galaxies, each with tens of billions of stars similar to our own Sun. To match the two images, select the x-ray image (the first one you loaded) by clicking with your mouse anywhere in that left hand image window and then do: Frame > match frames > WCS and Frame > lock crosshairs > WCS. Then Edit > crosshairs.
Now you can cruise around and see that the "point" sources in the x-ray light really correspond to entire galaxies in the visible picture!
