How far are the farthest things in these surveys?


Hi,

@ChristineM posted a good link to an answer for this question, for the SDSS survey (which isn’t as sensitive as the Legacy Surveys):
https://www.zooniverse.org/projects/zookeeper/galaxy-zoo/talk/1268/576934?

That red smudge is probably a high-redshift galaxy; it’ll be several billions of light-years distant.

Nearby is this quasar observed with spectroscopy by SDSS; at redshift 3, it’s like 10 billion light-years distant.

By the way, “distances” for high-redshift objects are very weird, because it’s the whole universe expanding making objects seem to be moving away from each other. (And that’s a lot of the reason we talk about redshift rather than distance; also it’s the thing we actually observe.)

cheers,
–dustin

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:grin:

Thank you for the kind comment.

I’m puzzled by this one close by that doesn’t seem to register on the image, even though it has lower red-shift than the one you pointed out…

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“Zwarn = 0x5” is the warning flag… “Zwarn” means a warning from the redshift fitter, and usually anything other than zero means a dubious result. In this case, extremely dubious (there really is nothing there)!

:rofl: no chance of the machines taking over just yet then…

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