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Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Thu Jan 19, 2023 9:37 pm
by Chris Peterson
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.
_
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Thu Jan 19, 2023 9:45 pm
by johnnydeep
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.
![Smile :-)](./images/smilies/icon_smile.gif)
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!):
[ EDIT: and I now see Chris posted the two in context in reply to my earlier post before I did myself! <sigh>]
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Fri Jan 20, 2023 8:28 pm
by Francesca
The double images of galaxies are known. See this (indicated to me by Dan Coe)
https://arxiv.org/abs/2211.13334
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Fri Jan 20, 2023 8:50 pm
by johnnydeep
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.
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Fri Jan 20, 2023 8:54 pm
by Chris Peterson
johnnydeep wrote: ↑Fri Jan 20, 2023 8:50 pm
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).
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Sat Jan 21, 2023 8:32 pm
by johnnydeep
Chris Peterson wrote: ↑Fri Jan 20, 2023 8:54 pm
johnnydeep wrote: ↑Fri Jan 20, 2023 8:50 pm
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 (3.18 MiB) Viewed 1621 times Figure 1. JWST/NIRCam false color image (R=F277W+F356W+F444W; G=F150W+F200W; B=F115W+F150W) of MACS0647. Multiple<br />images are indicated and numbered. Yellow circles mark lensed image systems previously identified in HST observations, and white circles<br />denote lensed systems newly identified with JWST. The red and green curves represent the macro critical curves corresponding to our dPIEeNFW and Glafic lens models, for a source at redshift zs = 4.8.](./download/file.php?id=46694&t=1&sid=e70eda6a49bfae6695ee9b3d76d09be7)
- Figure 1. JWST/NIRCam false color image (R=F277W+F356W+F444W; G=F150W+F200W; B=F115W+F150W) of MACS0647. Multiple
images are indicated and numbered. Yellow circles mark lensed image systems previously identified in HST observations, and white circles
denote lensed systems newly identified with JWST. The red and green curves represent the macro critical curves corresponding to our dPIEeNFW and Glafic lens models, for a source at redshift zs = 4.8.
Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Posted: Thu Feb 16, 2023 7:13 pm
by Fred the Cat
The
art of reconstructing details of gravitationally-lensed galaxies turns to
training its data to behave predicably. Training
Art sounds like a chore better left to experts.
![Yes. :yes:](./images/smilies/yes.gif)
I’d like to see the results in
clumps.
Clumping is fairly important in
astronomy,
cosmology, and
art. Art might have agreed.
![Rolling Eyes :roll:](./images/smilies/icon_rolleyes.gif)