APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

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Chris Peterson
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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by Chris Peterson » Thu Jan 19, 2023 9:37 pm

johnnydeep wrote: Thu Jan 19, 2023 9:08 pm
Francesca wrote: Thu Jan 19, 2023 8:53 pm I see in the picture (also in that by Hubble) two identical images of a galaxy. My question is whether this has been already noted. To see the first one, look at the star at the left of the center of the picture. It has six blue rays. Prolong the ray pointing up-right till a small red galaxy. The second image is approximately on the vertical line at the middle of the picture, just at the end of the left blue ray of another star, a bit less brilliant than that considered above.
There are two more objects that seem to be distorted mirror images one of the other.
I'm not sure I'm following your directions correctly. Can you post a pic with the two galaxies indicated? This are the two galaxies that I think you are referring to:


two red galaxies in jwst gravitational lensing pic.png


[ EDIT: nah, that can't be right. I give up. I need a pic! ]
I take it to be these two.
_
gals.jpg
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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by johnnydeep » Thu Jan 19, 2023 9:45 pm

Chris Peterson wrote: Thu Jan 19, 2023 9:33 pm
Francesca wrote: Thu Jan 19, 2023 8:53 pm I see in the picture (also in that by Hubble) two identical images of a galaxy. My question is whether this has been already noted. To see the first one, look at the star at the left of the center of the picture. It has six blue rays. Prolong the ray pointing up-right till a small red galaxy. The second image is approximately on the vertical line at the middle of the picture, just at the end of the left blue ray of another star, a bit less brilliant than that considered above.
There are two more objects that seem to be distorted mirror images one of the other.
Interesting catch. While the two objects appear very similar- really, too much for a coincidence IMO (and not mirrored)- I don't think they can be lensed images. You'd never have a pair of lensed images that look the same, given the nature of gravitational lensing distortion. Some kind of processing and stacking anomaly, maybe?
_
2gal.jpg
Well, Chris' ability to follow directions is obviously better than mine. :-) But with his pic, I was finally able to locate the two galaxies in context, which do really look identical (yes, this was quite an astute observation!):

two red galaxies in jwst gravitational lensing pic 2.png

[ EDIT: and I now see Chris posted the two in context in reply to my earlier post before I did myself! <sigh>]
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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by Francesca » Fri Jan 20, 2023 8:28 pm

The double images of galaxies are known. See this (indicated to me by Dan Coe)

https://arxiv.org/abs/2211.13334

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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by johnnydeep » Fri Jan 20, 2023 8:50 pm

Francesca wrote: Fri Jan 20, 2023 8:28 pm The double images of galaxies are known. See this (indicated to me by Dan Coe)

https://arxiv.org/abs/2211.13334
Isn't that article about lensed stars, not galaxies? The title is "Two lensed star candidates at z≃4.8 behind the galaxy cluster MACS J0647.7+7015"

Unless the double galaxies we've been discussing are also mentioned within. I admit I haven't read the article in detail.
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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by Chris Peterson » Fri Jan 20, 2023 8:54 pm

johnnydeep wrote: Fri Jan 20, 2023 8:50 pm
Francesca wrote: Fri Jan 20, 2023 8:28 pm The double images of galaxies are known. See this (indicated to me by Dan Coe)

https://arxiv.org/abs/2211.13334
Isn't that article about lensed stars, not galaxies? The title is "Two lensed star candidates at z≃4.8 behind the galaxy cluster MACS J0647.7+7015"

Unless the double galaxies we've been discussing are also mentioned within. I admit I haven't read the article in detail.
Yes, but note identified object 1 from the HST images (1.1, 1.2, and 1.3).
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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Post by johnnydeep » Sat Jan 21, 2023 8:32 pm

Chris Peterson wrote: Fri Jan 20, 2023 8:54 pm
johnnydeep wrote: Fri Jan 20, 2023 8:50 pm
Francesca wrote: Fri Jan 20, 2023 8:28 pm The double images of galaxies are known. See this (indicated to me by Dan Coe)

https://arxiv.org/abs/2211.13334
Isn't that article about lensed stars, not galaxies? The title is "Two lensed star candidates at z≃4.8 behind the galaxy cluster MACS J0647.7+7015"

Unless the double galaxies we've been discussing are also mentioned within. I admit I haven't read the article in detail.
Yes, but note identified object 1 from the HST images (1.1, 1.2, and 1.3).
Ah. I take it you must be referring to these three marked objects from the PDF:

lwst hubble grav lensing multiple.png
lwst hubble grav lensing multiple table.png
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