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Understanding redshift surveys

by batboy
Tags: redshift, surveys
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batboy
#1
Apr8-06, 12:18 AM
P: 13
....With Galaxy Explorer 2.0


Hi!

I'm doing some personal reaserch on Sloan Digital Sky Survey, and I was wondering if anyone here uses this software?


If so, could you tell me what the center is?

For details of the SDSS project check the websites:
GalaxyExplorer: a 3D visualization tool: http://cas.sdss.org/dr4/en/help/download/
http://www.sdss.org/
http://skyserver.sdss.org/




thank you
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matt.o
#2
Apr8-06, 02:01 AM
P: 391
I use the radial search and photometric catalogues a bit. What do you need to know specifically?
batboy
#3
Apr8-06, 03:36 PM
P: 13
Sorry, should've uploaded that from the beginning. I zoomed out as far I could to give some perspective. Specifically, I just wanted get some perspective about the middle.


http://img446.imageshack.us/img446/9...31255pm2vf.png


Here is what the read-me says.

This program shows you the 3D distribution of galaxies observed by the Sloan
Digital Sky Survey. The data consists of the 3D positions of 131,000 galaxies
observed to date. Note, how galaxies tend to be close to one another, forming
walls and filaments.

The data is located on several 'wings', these only reflect the sky coverage,
i.e. the observations are still rather incomplete. When finished, in 2005,
there will have a full three-dimensional map of a large cone in the Northern
Sky. There will always be a gap around the plane of the Milky Way -- there is
too much dust there to see through, therefore that region was avoided.

SpaceTiger
#4
Apr8-06, 04:50 PM
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Understanding redshift surveys

Quote Quote by batboy
If so, could you tell me what the center is?
The center is us (the Milky Way). The pie slices are the parts of the universe that we can see with SDSS. A galaxy's radial distance from us is estimated from its redshift.
batboy
#5
Apr12-06, 09:43 AM
P: 13
Thank you, SpaceTiger and matt.o.
Chronos
#6
Apr13-06, 12:27 AM
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I recommend VizieR if you wish to study the published data from SDSS, or other redshift surveys: http://cdsweb.u-strasbg.fr/cats/Cats.htx. I use HTML format and copy it to an MS spreadsheet:


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