Comments on: Galaxy Zoo Press

By: Ann Croft

Ann Croft — Tue, 17 Jul 2007 23:41:46 +0000

http://cas.sdss.org/astro/en/tools/chart/chart.asp?ra=177.15779398&dec=56.94754443

Would you approve of that as a merger, emily?

By: Ann Croft

Ann Croft — Tue, 17 Jul 2007 23:34:53 +0000

The tutorial was updated after I asked the question!
The pictures I’m saving for my son’s use, they’re not necessarily what I classed them as when using Galaxy Zoo. Sorry for the confusion.

By: Maile

Maile — Mon, 16 Jul 2007 16:15:36 +0000

Emily,
I’d like to point out that Part 3 of the tutorial was definitely NOT there when I started classifying. I, like Ann, had questions about the green streaks and emailed asking about them. Obviously this was a common point of confusion since the galaxy zoo people added a whole section into the tutorial.

However, your post did make me curious about what in the tutorial could possibly have answered my green streak question. I actually still had the tutorial open in a window from the beginning of last week, so I hit refresh and BOOM, there was the section. So you were right, it was definitely good to go back and read the tutorial again since they have added some additional and helpful information.

I’ve found mergers to be particularly tricky in part, I think, to the fact that, in the tutorial, the top middle picture in 1C “merging galaxies” looks similar to the bottom middle picture in 2B which is identified as an anti-clockwise spiral. I actually wrote to ask about this and received the following extremely helpful reply from Dr. Kate Land:

I think the trick is to look closely at the
centre of the picture and the flow of the arms - a spiral will have
just one nucleus and symmetric arms continuously running from one to the
other. While a merger will be a bit more messy - different looking arms
(not symmetric) and a blotchy nucleus.

Thought I would pass that on in case it helps anyone else with mergers!

Happy classifying, and thanks to Chris and the other folks for the added information on the tutorial page. Its very helpful and it is always good to know that you guys are listening and responding to feedback.

By: emily

emily — Sat, 14 Jul 2007 20:55:05 +0000

erm, hi Ann Croft. Just looked at your piccies and this is a friendly note to say “read the tutorial again”. You’re classifying loads of galaxies as “mergers” and they’re not. there just a galaxy with another galaxy or star apparently close in the picture! the important thing to determine if they are merging or not is if they are obviously interacting, gravitationally in any way. Otherwise they are not merging. I think you need to read the tutorial anyway, because I notice you asked “what is the green line”, well that is carefully explained in the tutorial as being a satelite track. this is just friendly advice, i’m only saying this because its important to get these classifications as good as possible, and mergers are relatively rare. i guess you were just excited to get started! i know i was.

By: TJ

TJ — Fri, 13 Jul 2007 18:22:44 +0000

After doing a couple hundred I was starting to burn out … suddenly there was a kelly-green star in the foreground. Whoa! Many of the images are quite blurry, but (imagine the distance!) in some cases that adds to the mystery. Oh yeah … being the first to see these things: who *knows* what you might find? Hooked!

By: chrislintott

chrislintott — Thu, 12 Jul 2007 21:26:13 +0000

Given the success we’ve had, we’ll eventually get multiple classifications of each object. Please make the best guess you can about the central object, whenever you can. Don’t know should be abutton of last resort.

By: Kevin McNulty

Kevin McNulty — Thu, 12 Jul 2007 21:13:11 +0000

Poor site is not working tonight ( more weight than a nuetron star!) so went through the disciplines again and still get confused as to what is merging and spiral and eliptical and feel bad marking star don’t know, will our mistakes corrupt the final results? Love this project big time. Oh well site is down the missus will be pleased.

By: Steve Gannon

Steve Gannon — Thu, 12 Jul 2007 18:39:12 +0000

Hello Chris!

Thanks so much for the opportunity we all have been given to assist with your research. Very cool stuff here! A few questions though:

It appears that quite a few images that resemble ellipticals, are actually out of focus spirals. How will you go about sorting out the miss-identified classifications? I have been classifying round blobs as edge on spirals, elongated blobs as elliptical.

I have noted that a large percentage ( > %95) of images are red shifted blobs or quite out of focus. Are we to classify as Star / Don’t know?

Thanks again and great job!

By: Alice Sheppard

Alice Sheppard — Thu, 12 Jul 2007 16:48:20 +0000

Come to think of it, Annie, I just checked your pictures and the poor zookeepers will have a tough time, because I wouldn’t have called all your mergers mergers. Merger 3 for instance just looks like one perhaps a long way behind/in front of the other. Perhaps I’m just too blind to see the interaction? What should we be looking for?

By: Alice Sheppard

Alice Sheppard — Thu, 12 Jul 2007 16:46:06 +0000

Aha, I was wondering what on earth those blue and green lines were. I was making a note of them as “doubtless man-made interference but WHAT ON EARTH . . . ?”

What about the uniform pink, orange or bright red backgrounds? Presumably way over-magnified? I’m calling them Star/Don’t know!

I love the “Hi Alice” that appears in the top left-hand corner when I log in. Isn’t it a sweet site? Can’t wait for the discussion forum to be open; can we share images of the really good ones?