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Old 20-June-2008, 10:23 PM
RickJ RickJ is offline
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Default Distances can be deceiving

What with nearly two months of clouds or full moon I took a second look at my shot of Arp 206. There were many background galaxies. Most I found nothing on but 9 objects were listed in NED. While the background galaxies all looked very distant that wasn't the case. One is likely a member of the Arp 206 system showing a radial velocity putting it slightly closer than the two main galaxies. It must be a really tiny galaxy. All others were at least 560 million light years to over 2 million light years. Three are quasars though one galaxy looks the same as the three QSOs. Below is a cropped portion of the original image with 9 objects marked can you figure out which is the close one and which are the very distant ones? Size and brightness don't help much!



Below I've listed them in order of increasing distance. How many did you get right?

.
.
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Galaxies
2: SDSS J105205.52+362836.3 magnitude 17.9 33 million light years
4: PGC 2081645 magnitude 17.1 Distance 563 million light years
5: SDSS J105133.55+363053.3 magnitude 17.9 570 million light years
6: SDSS J105141.30+363653.4 magnitude 16.1 570 million light years
1: SDSS J105243.56+362925.6 magnitude 17.9 1.676 billion light years
3: SDSS J105203.05+363205.0 magnitude 18.9 2.786 billion light years

QSOs (corrected)
7: CSO 295 magnitude 16.8 5.66 billion light years
8: SDSS J105158.68+364326.1 19.0 magnitude 7.321 billion light years
9: SDSS J105242.50+364335.7 19.3 magnitude 8.09 billion light years

When originally posted I reversed 7 and 8. Got to type these up when I'm not so tired.

Rick

Last edited by RickJ : 21-June-2008 at 09:36 PM. Reason: Corrected error on 7 an 8
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Old 21-June-2008, 05:28 AM
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redshifter redshifter is offline
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Awesome pic! Great summary as well, very interesting.
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Old 21-June-2008, 06:54 AM
Torsten Torsten is offline
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8.09 billion light years!

I'm stunned.
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Old 21-June-2008, 02:06 PM
JAICOA JAICOA is offline
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Great info and close-up image Rick!, It sure is decieving if you look at the image quickly but still i was not even close. Great Job and Clear Skies
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Old 21-June-2008, 09:38 PM
RickJ RickJ is offline
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Drat -- I see I reversed 7 and 8. Only one person emailed me to ask why 7 was so bright yet listed as mag 19. Easy when you can't type straight. I've corrected the original post. Sorry for the error.

Rick
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Old 21-June-2008, 09:47 PM
RickJ RickJ is offline
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Quote:
Originally Posted by Torsten View Post
8.09 billion light years!

I'm stunned.
I've noted further ones in other posts. For example see:
Too many galaxies? Abell 1367

Note these are light travel distances. The distance the light traveled to get to us. Since the universe has been expanding all those 8 billion years it was much closer than that when light left it but expansion along the way caused it to take a bit over 8 billion years to reach us. Currently it is much farther away. That assumes it still exists which is unlikely.

Rick
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