Author Topic: Merger Checking Examples  (Read 38705 times)

fluffyporcupine

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Re: Merger Checking Examples
« Reply #180 on: March 11, 2009, 08:22:23 pm »
I've seen a lot of discussion involving z redshift when it comes to determining whether something is a merger or not.  My questions are these:

Is there a way to analyze z redshift prior to finishing our classification in the zoo?  It seems like we just have to guess whether something is a merger or not, finish our classifying, and then check out the SDSS data once we're done.  Edit - Answered by Tom in another thread

If there is no spectrum data for a given galaxy, I can't seem to find a z redshift value.  Is there a place I can find it, or is there just no data available?  How do you tell if there's a merger happening if there's no z redshift data?  Best guess based on the shape/disturbance/etc.?

Thanks for your help!  Sorry if these questions have already been answered somewhere before; if they have, just a link to that post will be fine  :)
best way to tell is if they are interacting - so disruption and tidal tails. If you could do this on purely redshift data there would be no galaxyzoo, the computers would get all the fun!

david_nw

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Re: Merger Checking Examples
« Reply #181 on: April 16, 2009, 09:59:55 pm »



SDSS 588017992833826997

Right and top left?  Both tag 3 with z of 0.13 and 0.14 respectively and I think a bit of distortion in the big elliptical to the right.  But it isn't obvious...

?

david_nw

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Re: Merger Checking Examples
« Reply #182 on: April 16, 2009, 10:12:34 pm »

This has been posted on the overlap thread without comment. 

I too thought it overlap but then noticed red shifts for both at around 0.06 and started thinking I could see some distortion where they join - especially above the top of the vertical galaxy.     :-\



SDSS 587739133489709248

david_nw

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Re: Merger Checking Examples
« Reply #183 on: April 16, 2009, 10:21:23 pm »
Both at z of 0.15 with what is surely a fair amount of distortion in the brighter galaxy and possibly the other one as well.   But fuzzy. 





SDSS 587739131883028688 - can't find any other reference.

david_nw

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david_nw

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Re: Merger Checking Examples
« Reply #185 on: April 19, 2009, 01:57:51 pm »
Still struggling with identifying mergers.  Some distortion here? ...but v fuzzy   :-\



http://cas.sdss.org/dr7/en/tools/quicklook/quickobj.asp?id=587742013818470428

Alice

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Re: Merger Checking Examples
« Reply #186 on: April 19, 2009, 05:19:46 pm »
Those are both very tricky, but I think I'd say no to both of them.

weezerd

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Re: Merger Checking Examples
« Reply #187 on: April 19, 2009, 05:56:39 pm »


http://cas.sdss.org/dr7/en/tools/quicklook/quickobj.asp?id=588011502596653250

Well in my opinion, this one looks like a mirror image of Alice's avatar...notwithstanding the colour difference?
Oh let me just a moment stay
where time is not and angels play the paeans of the galaxies;
then speed the stardust on its flight
to change dread darkness into light, cold chaos into ecstasy!

Alice

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Re: Merger Checking Examples
« Reply #188 on: April 19, 2009, 08:44:09 pm »
, but ;D ;D ;D ;D ;D

david_nw

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Re: Merger Checking Examples
« Reply #189 on: April 25, 2009, 09:14:10 am »
« Last Edit: July 20, 2009, 11:03:29 pm by david_nw »

Dan1el

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Re: Merger Checking Examples
« Reply #190 on: May 27, 2009, 11:13:51 am »
I feel like I just had my eyes taken out and put back in after a brief shake...

This is so revealing thanks all of you.

david_nw

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Re: Merger Checking Examples
« Reply #191 on: June 24, 2009, 10:32:39 pm »




http://cas.sdss.org/dr7/en/tools/quicklook/quickobj.asp?id=587734621633446090

Already posted in the overlaps thread but I think they are merging.  Z=0.0511 and Z=0.0507!