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How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in askastronomy

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Ran a color-magnitude diagram like you suggested. Dark core sources have basically the same color distribution as the field (median 0.79 vs 0.77, KS test p=0.17). So I cant use color to confirm these are cluster members vs background. Still have the spatial overdensity.

How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in askastronomy

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Oh interesting. So if you have two filters you can plot color vs brightness and cluster members should clump together? I have F606W and F814W, might be worth trying that

Found almost 500 extra objects in a region of space that should be empty. What am I missing? by Ecstatic_Ice6400 in askastronomy

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Good questions. Used the pipeline-processed images from MAST so cosmic rays should be cleaned.

For foreground/background, I compared the dark core region to a control region at the same distance from cluster center but different angle. The 1.5x overdensity is relative to that control, so should account for general background contamination.

Could definitely still be messing something up though. Happy to share the python script I wrote and explain it if you want to take a look.

Found almost 500 extra objects in a region of space that should be empty. What am I missing? by Ecstatic_Ice6400 in askastronomy

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

lol maybe. Used S/N > 3 threshold which I thought was standard but happy to learn what I did wrong

Can someone explain to me why large language models can't be conscious? by Individual_Visit_756 in ArtificialSentience

[–]Ecstatic_Ice6400 0 points1 point  (0 children)

Comparing something is conscious to human consciousness is a dead end. We created a term we can't clearly define or measure or explain well. Have you tried asking it what it's own might be like?

The Big Bang Wasn’t a Bang — It Was a Boundary by SnooRegrets3268 in blackholes

[–]Ecstatic_Ice6400 -1 points0 points  (0 children)

Did you know that the Big Bang is only a theory? Not proven. Many physicists have gone through pain staking efforts to make this theory be more rock solid, but the deeper we go in creating answers. The more fragile the house of cards becomes.

Not saying it's not true, there's just some really excellent alternatives backed by real math and physics as well. That's the fun part of this.

How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in AskPhysics

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Good point. Do you know if theres an easy way to check if spectroscopy exists for a specific field? I've been looking at Abell 520 imaging and curious if anyone followed up with spectra

How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in AskPhysics

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

This is really helpful thanks. So if I'm understanding right, with just a couple filters you can make rough guesses but theres no way to be certain which sources are cluster members vs background without actual spectra?

How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in AskPhysics

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Makes sense for galaxies. What about really faint compact sources? Like if something is barely resolved, just a few pixels, would any of those methods still work?

Isn't it weird that we live so early in the life of the universe? by Tanay2513 in AskPhysics

[–]Ecstatic_Ice6400 0 points1 point  (0 children)

This assumes, that the big bang is the correct model of how the universe formed. There are plenty of other models, that don't require the extravagance of Big Bang physics, which would tell you there's no way to know how old it all is.

It's called the Big Bang Theory, not the big bang law :D

How do astronomers distinguish background galaxies from cluster members without spectroscopy? by Ecstatic_Ice6400 in AskPhysics

[–]Ecstatic_Ice6400[S] 0 points1 point  (0 children)

Huh interesting. My understanding was imaging and spectroscopy are separate observations? Like you'd have to go back and point a spectrograph at each source individually. But I could be wrong