Page 1 of 1
APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 4:05 am
by APOD Robot
SN Requiem: A Supernova Seen Three Times So Far
Explanation: We've seen this same supernova three times -- when will we see it a fourth? When a distant star explodes in a
supernova, we're lucky if we see it even once. In
the case of AT 2016jka ("SN Requiem"), because the exploding star happened to be lined up behind the center of a
galaxy cluster (MACS J0138 in this case), a comparison of
Hubble Space Telescope images demonstrate that we saw it three times. These three
supernova images are highlighted in circles near the bottom of the left frame taken in 2016. On the right frame, taken in 2019, the circles are empty because all three images of the single supernova had faded.
Computer modeling of the cluster lens, however, indicates that a fourth image of the same
supernova should eventually appear in the upper circle on the right image. But when? The best
models predict this will happen in
2037, but this date is uncertain by about two years because of ambiguities in the mass distribution of the
cluster lens and the brightness history of the stellar explosion. With refined
predictions and vigilant monitoring,
Earthlings living 16 years from now may be able to catch this fourth image -- and perhaps learn more about both galaxy clusters and supernovas at once.
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 10:25 am
by heehaw
Wow! Superb science!
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 11:37 am
by orin stepanek
Courtesy of gravity lens!
Cute little Earthlings!
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 11:45 am
by irishlazz
Now I can't not see the kitten faces! =o)
The narrative doesn't indicate that the 2016 image is a composite, so I am assuming a single image. So, would it be more accurate to say we saw it in 3 places at one time rather than 3 times?
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 12:04 pm
by Ann
irishlazz wrote: ↑Tue Nov 02, 2021 11:45 am
Now I can't not see the kitten faces! =o)
You can't?
The narrative doesn't indicate that the 2016 image is a composite, so I am assuming a single image. So, would it be more accurate to say we saw it in 3 places at one time rather than 3 times?
Well, that's interesting. A supernova will only be bright for a very limited time. If you take a look at the 2016 image, you can see that the middle supernova image is brighter and whiter than the two others and therefore more recent. Still, I too find it quite remarkable that we should see three versions of the same supernova in the same non-composite Hubble image.
Am I right to assume that the supernova exploded in that arc-shaped orange galaxy that we can see three - no, make that four - versions of (since the bottom one is clearly made up of two overlapping images)?
Ann
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 12:17 pm
by hanochbernath
THE RIGHT IMAGE SEEMS SOMEWHAT SHARPER THN THE LEFT. WHAT IS THE DIFFERENCE?
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 1:05 pm
by neufer
irishlazz wrote: ↑Tue Nov 02, 2021 11:45 am
The narrative doesn't indicate that the 2016 image is a composite, so I am assuming a single image. So, would it be more accurate to say we saw it in 3 places at one time rather than 3 times?
We are dealing with the
space-time continuum here so words are a little tricky.
- 3 times is good.
3 directions is good.
3 places is questionable.
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 1:33 pm
by E Fish
That is absolutely fascinating. I didn't even know we could predict when and where new images would show up, not even with a margin of two years. I hadn't thought about lensing images changing over time. I definitely learned something new today.
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 2:26 pm
by Sa Ji Tario
irishlazz wrote: ↑Tue Nov 02, 2021 11:45 am
Now I can't not see the kitten faces! =o)
The narrative doesn't indicate that the 2016 image is a composite, so I am assuming a single image. So, would it be more accurate to say we saw it in 3 places at one time rather than 3 times?
It seems OK to me
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 2:31 pm
by Sa Ji Tario
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 8:24 pm
by johnnydeep
Something doesn't make sense to me. One of the links says the SN is 10 Gly away and the galaxy cluster (and accompanying dark matter) is 4 Gly away. Yet, the longest path taken by the light from the SN to get to us is only about 20 light years longer (2037-2016)? I would have expected some much larger difference in path lengths. How did we luck out with a mere 20 year wait?
For context, one of the links says this about what's going on:
Each magnified image takes a different route through the cluster and arrives at Earth at a different time, due, in part, to differences in the length of the pathways the supernova light followed.
"Whenever some light passes near a very massive object, like a galaxy or galaxy cluster, the warping of space-time that Einstein's theory of general relativity tells us is present for any mass, delays the travel of light around that mass," Rodney said.
He compares the supernova's various light paths to several trains that leave a station at the same time, all traveling at the same speed and bound for the same location. Each train, however, takes a different route, and the distance for each route is not the same. Because the trains travel over different track lengths across different terrain, they do not arrive at their destination at the same time.
In addition, the lensed supernova image predicted to appear in 2037 lags behind the other images of the same supernova because its light travels directly through the middle of the cluster, where the densest amount of dark matter resides. The immense mass of the cluster bends the light, producing the longer time delay. "This is the last one to arrive because it's like the train that has to go deep down into a valley and climb back out again. That's the slowest kind of trip for light," Rodney explained.
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Tue Nov 02, 2021 11:01 pm
by lostsoul
I think the reason you can see the three images is gravitational lensing, Einstein's theory which was verified seeing objects behind massive galaxies. If I am correct I wish you would have said so in the write up so the picture would be more understandable.
Re: APOD: SN Requiem: A Supernova Seen Three... (2021 Nov 02)
Posted: Wed Nov 03, 2021 7:19 pm
by johnnydeep
lostsoul wrote: ↑Tue Nov 02, 2021 11:01 pm
I think the reason you can see the three images is gravitational lensing, Einstein's theory which was verified seeing objects behind massive galaxies. If I am correct I wish you would have said so in the write up so the picture would be more understandable.
True. A "cluster lens" is indeed mentioned in the description, but not "gravitational lensing" specifically. However, the
the case of AT 2016jka link in the desc does clarify it further.
