Scientific rationale: Why we need your participation.
Hello Galaxy Zoo user,

We would like you to answer the questions, and perform the tasks on the main classification page for the following scientific reasons:

1) The automated galaxy light profile fitting, performed by the Sloan Digital Sky Survey is used extensively in studies of galaxy shape, for example in weak gravitational lensing. By answering the question "Does the ellipse describe the shape of the galaxy well?" we are testing the reliability of this pipeline for a selection of galaxies.

2) We ask you to alter the ellipse fitting the light profile, if the above is false. This allows us to see if there is a systematic offset [a computer bug always making the same type of error] between what you and the pipeline think the light profile is, which we then might try to compensate for.

3) When we ask the question "Does this Galaxy have a bar?" we would like to know what is the fraction of galaxies which have a bar. The existence of bars may effect a galaxy's properties, and we need your help testing for this. Galaxy Zoo2 has already done this, but at a different resolution, and we can use this as sanity check. We stress, that not all galaxies in the sample will have bars.

4) We then ask you to draw the galaxy bar if it has one, and describe it's width and how it connects to the galaxy's spiral arms if there are any. We need this information to understand how/if the presence of bars is indicative of some other galaxy property that we can later test for. We ask you to identify how the spiral arms attach to the bar as this will give us clues to the link between bar and spiral structures.

Without the dedicated help of you, our users, this work would take professionals years to perform. Despite developments in computer science, these types of tasks are still more easily achieved using humans.


Is the ellipse a good fit to the galaxy? Close This Window
You may need to adjust the zoom to see the galaxy. This is achieved by clicking on the map interface tools in the top right hand corner of the map
Example where the ellipse is a good fit          Example where the ellipse is not a good fit        
Please alter the ellipse to cover the galaxy Close This Window
To adjust the ellipse you can either click on the and buttons to change the major axis, minor axis, or the angle of the ellipse. The center cannot be changed.
Alternatively, you may draw the ellipse by hand, by moving your mouse over the ellipse, and dragging the bright squares to a new location and then double clicking on them. You may also use the and buttons to fine tune the ellipse.
Does this galaxy have a bar? Close This Window
Example of a galaxy with a bar         Example of a galaxy without a bar        
Please draw the bar on the galaxy Close This Window
To draw a bar, move the mouse to the start of the bar and click to begin drawing. Then double click at the end of the bar. You can adjust the line by dragging the squares at the end of the lines which appear when you move your mouse over the line.
If you wish to redraw the line, click and then to begin drawing.
Adjust the Thickness of the bar Close This Window
Use the and to adjust the thickness of the ellipse until it covers the outside of the bar you just drew. Then press submit
How are the bars attached to the spiral arms? Close This Window
The bar ends in a ring, and the spiral arms come out of the ring     The spiral arms begin at the end of the bar     Some mixture of the two      Only a ring no spiral arms     
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