Author Topic: Wednesday 18th Mar 2009: Clusters  (Read 1349 times)

waveney

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Wednesday 18th Mar 2009: Clusters
« on: March 18, 2009, 07:21:48 am »
Last week Teresa8 asked about the blue thing in this picture:

588011503136145442
No its not a Voorwerp, but a hot blue star.  But I noticed the star trails to NW/SE and zoomed out:

Now one can see several hot blue stars, and a pair of beautiful star trails extending from the galaxy.  Star trails like this are indicative of interactions with another galaxy.  Lets Zoom out a bit more:

There in the foreground are yet more hot blue stars - it is a nearby cluster of hot new stars.  Looking to the South there are a pair of large galaxies. 

Although none of these have SDSS spectra, NED has spectra for our spiral and the large elliptical to the South - which are virtually identical.  Now I always say don't use redshift to find if galaxies are merging, but rather use it as a way of eliminating a merger if they are significantly different.  Better clues for mergers are star trails (Yay), distortion, star forming, dual cores and common halos.

Our pretty spiral is interacting with at least one of the other galaxies to the south.  So we have a star cluster and a galaxy cluster.

Enjoy!
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AlexandredOr

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #1 on: March 18, 2009, 07:23:36 am »
Wowww. Great ! Thanks waveney !

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Pat

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #2 on: March 18, 2009, 07:24:02 am »
Thanks Waveney. :) Another informative OOTD. :) And I like the stars!!! :)

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AlexandredOr

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #3 on: March 18, 2009, 07:25:39 am »
Thanks Waveney. :) Another informative OOTD. :) And I like the stars!!! :)

Yes... Waiting for Liz opinion :D

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Caro

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #4 on: March 18, 2009, 07:33:08 am »
Thanks waveney. Very interesting and pretty pictures.  :)
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citisue

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #5 on: March 18, 2009, 07:46:59 am »
 :D :D :D  Very nice Waveney ;D  Love those blue stars ;D ;D ;D
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Karma

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #6 on: March 18, 2009, 11:11:10 pm »
Interestin stuff. I couldn't find the star cluster in SIMBAD. I wonder how many such clusters are lurking in the SDSS waiting to be picked up. 8)
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Alice

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #7 on: March 19, 2009, 12:15:31 am »
That's a wonderful one. 8)

Half65

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #8 on: March 19, 2009, 09:59:26 pm »
Great one waveney.

jules

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Re: Wednesday 18th Mar 2009: Clusters
« Reply #9 on: March 19, 2009, 11:31:20 pm »
Interestin stuff. I couldn't find the star cluster in SIMBAD. I wonder how many such clusters are lurking in the SDSS waiting to be picked up. 8)
They are definitely all blue and in the same area of sky but it is difficult to say without spectral classifications if this really is a star cluster or just a stellar association (ie stars that have wandered too far apart to be a cluster but are in a higher concentration than the background stars). However, there must be many undiscovered star clusters out there.... :)