New ATLAS images for Radio Galaxy Zoo
Dear Radio Galaxy Zoo volunteers,
Thanks again for all your help so far in classifying radio galaxies through RGZ. We’re rapidly approaching our 1 millionth classification, probably by the end of this week (Jan 15-17) at the current rate. Don’t forget that we’ll be awarding prizes!
In the meantime, we’re excited to announce that we’ve just finished processing a new set of images for RGZ. There are 2,461 new images in total: the radio images are from a survey named ATLAS, carried out by the ATCA telescope in Australia. The corresponding infrared images come from the Spitzer Space Telescope as part of a survey named SWIRE.
Due to the differences in telescopes (ATCA has fewer dishes and a different arrangement of them than the VLA, while Spitzer has a much bigger mirror than WISE) and the depths of the two surveys, the data will look a little bit different. If you’ve done lots of classifications on Radio Galaxy Zoo already, you may notice more elongated radio beams in the ATLAS data, as well as a slightly larger size of the smaller unresolved noise spots. ATLAS can also detect fainter objects than the FIRST survey.
The new SWIRE infrared images have about twice the angular resolution of WISE (it can separate objects down to 3 arcseconds apart) and are more than 20 times as sensitive. That means you’ll likely see more infrared objects in the new images, and might have more choices for likely host galaxies for radio emission.
Since the images are mostly similar, the task for RGZ hasn’t changed (in fact, the original tutorial image was from ATLAS data). We’re still asking you to pick out individual radio components (or groups of components) and match them to their IR host galaxies. The new images will be randomly mixed in with the older images; you should see an ATLAS image every 6th or 7th classification, on average. If you’re curious whether a galaxy you’ve just classified is in ATLAS, the easiest way is to look at it in Talk: the new galaxy names will begin with a “C” (eg, “CI3180”) and will have declinations that are negative (eg, -27.782) showing that they’re in the Southern Hemisphere.
We’ll post a longer blog post very shortly with more information on ATLAS, SWIRE, and what we’re hoping to learn from these new images. In the meantime, please post here or on Talk if you have any questions!
And keep up the classifications in the next few days — hopefully you can be our 1 millionth image!