Author Topic: Do you classify part or all of the image?  (Read 16211 times)

Antirius

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Do you classify part or all of the image?
« on: August 01, 2007, 02:57:45 pm »
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587736543086379123

This seems to be somehing at the edge of or behind the galaxy.
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Halibut

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Re: Object at edge of galaxy
« Reply #1 on: August 01, 2007, 09:07:28 pm »
With these ones, we've been told by the zookeepers to classify the whole of the galaxy as one instead of just the object in the corss hairs, which zoomed out looks like a spiral edge-on.

fluffyporcupine

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Do you classify part or all of the image?
« Reply #2 on: August 10, 2007, 08:35:31 pm »
This seem sto get asked a lot, Zookeeper kevins reply was:
Hi,

Please classify the morphology of the HOST GALAXY. In this case, a spiral.

We will add this to the FAQ.

Thanks!

it was in this thread: http://www.galaxyzooforum.org/index.php?topic=325.0

Hope it helps!

Jaina

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Re: Do you classify part or all of the image?
« Reply #3 on: August 10, 2007, 08:41:39 pm »
I move to sticky this topic so that people can find it more easily.
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Megalodon99

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Re: Do you classify part or all of the image?
« Reply #4 on: August 10, 2007, 09:55:18 pm »
I also move to sticky it.

Alice

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Re: Do you classify part or all of the image?
« Reply #5 on: August 10, 2007, 10:40:15 pm »
All right, all right, I'll stickify this thread  ;D
(Zookeepers - if you object I'll unstick it. I'm not stuck-up about my moderating.)

Jaina

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Re: Do you classify part or all of the image?
« Reply #6 on: August 10, 2007, 11:07:09 pm »
Horray!  Many thanks, Alice!  8)
The heavens declare the glory of God; the sky displays his handiwork. (Ps. 19:1)

Alwaysthinking

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Re: Do you classify part or all of the image?
« Reply #7 on: August 14, 2007, 12:43:59 am »
I thought you were supposed to classify whichever one was in the middle… :-\

speedymarie

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Re: Do you classify part or all of the image?
« Reply #8 on: August 14, 2007, 04:37:28 pm »
I thought you were supposed to classify whichever one was in the middle… :-\
Sometimes a part of a galaxy will be targeted, especially when the galaxy is very nearby. For example, I got a target that was a bright blue, heavy star-forming, outer arm of the Pinwheel Galaxy. Looking at the target I was presented, zoomed way in, it looked like a blue irregular. But if you zoomed way, way out, you discovered that it was an outer arm of a large, nearby galaxy. In that case, I would classify the entire galaxy (a spiral), rather than just the arm that was my target (what looked like a blue irregular close up).

Now, if you get a picture that has several different galaxies in it, then yes, you'd classify whichever was in the middle, the target.

Hope that helps!

Kukakokeke

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Re: Object at edge of galaxy
« Reply #9 on: August 17, 2007, 05:32:23 am »
I have the same picture today. In my opinion it is maybe merger or overlapped pair of galaxies. In inverted picture you can see second nucleus on object in lower right edge.



Sorry Halibut, but I don't agree your opinion for classify in this case. In case that object is one piece of galaxy, your comments are right.

carwotcar

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Re: Do you classify part or all of the image?
« Reply #10 on: August 20, 2007, 04:00:49 pm »
In some cases galaxies have smaller satalite galaxies as does our galaxy that is what you might be seeing

altymczuk

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Re: Do you classify part or all of the image?
« Reply #11 on: September 09, 2007, 08:11:00 pm »
See neither an overlap nor a merger. CW spiral.
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buck1127

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Re: Do you classify part or all of the image?
« Reply #12 on: July 24, 2008, 02:20:10 am »
I'm not sure if this topic is covered elsewhere, though I feel it probably must be since it is something I have questions about rather frequently.  My question is:  How can you tell when the target might be a distant galaxy behind the larger host galaxy?  As such, I wouldn't think classification of the host is what they're looking for.

Other cases include ones where forground stars are pinpointed as the targets inside a larger host galaxy, so when you see these, you might assume it's targeting a part of the galaxy and classify it rather than noticing it's actaully a STAR.

the one below is one that falls in this category


http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587741709406896132

If you click on the link it shows in SDSS that the targeted object is a STAR, so shouldn't it be classified as S/DK??

.....and if the target specClass is "GALAXY", how can you be sure that it isn't gating on a distant galaxy behind (or maybe even in front of) the larger one?????

Any clarrification would be greatly appreciated........and, if this has already been addressed elsewhere, please forgive me.

thanks
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rat

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Re: Do you classify part or all of the image?
« Reply #13 on: February 15, 2009, 10:20:42 pm »
I'm not sure if this topic is covered elsewhere, though I feel it probably must be since it is something I have questions about rather frequently.  My question is:  How can you tell when the target might be a distant galaxy behind the larger host galaxy?  As such, I wouldn't think classification of the host is what they're looking for.

Other cases include ones where forground stars are pinpointed as the targets inside a larger host galaxy, so when you see these, you might assume it's targeting a part of the galaxy and classify it rather than noticing it's actaully a STAR.

the one below is one that falls in this category


http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587741709406896132

If you click on the link it shows in SDSS that the targeted object is a STAR, so shouldn't it be classified as S/DK??

.....and if the target specClass is "GALAXY", how can you be sure that it isn't gating on a distant galaxy behind (or maybe even in front of) the larger one?????

Any clarrification would be greatly appreciated........and, if this has already been addressed elsewhere, please forgive me.

thanks

We've been told to classify without looking at the SDSS data: http://www.galaxyzooforum.org/index.php?topic=273214.msg226225#msg226225

david walland

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How do I go back to correctly classify a galaxy?
« Reply #14 on: August 14, 2009, 12:58:09 pm »
I was whizzing through galaxies when up came what looked exactly like a star, but without the usual 4 "spikes".  So I classified it as a star or artifact.

When I could go into the image and zoome out, I quickly realised that this was not a star but the centre of a nearby elliptical galaxy.  How do I go back to the thing and put a correct and meaningful classification in place of the nonsense I have written?  How do I zoom in and out *before* classifying?

Regards

David Walland