SN Refsdale

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Trippy, Mar 7, 2015.

  1. Trippy ALEA IACTA EST Staff Member

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  3. paddoboy Valued Senior Member

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  5. paddoboy Valued Senior Member

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    I love the final comment in the video link number 2.....
    "The Stars keep lighting candles for him". [Einstein]
    All "doubting Thomas's" and alternative hypothesis pushers, should be tied down and forced to watch both videos illustrating this most amazing observationally verified concept of GR.
     
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  7. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Very nice. But so far, it is not quite that amazing, as it shows four images, with only one showing the supernova. It is projected that, had we been looking, we'd 've seen a supernova image a few years ago; and it is predicted that we'll see one again in a few more years. That is when it will be spectacular, to see it go off again, due to the longer path-length due to the gravitational lensing making for a several-year delay in the time for the photons to arrive. One can be certain that we'll have 'scopes trained on that region for the next flare-up!
     
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  8. RajeshTrivedi Valued Senior Member

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    There is one striking issue involved in this.....the lensing object (Galaxy in this case) is asymmetrically placed with respect to lensed object (SN), and hence we are able to see variable distance in spatial images....The point is as per maths, around any asymmetrical lensing object can we not find a point (or a path) which will focus on the Earth (Observer), suggesting that we should see many more lenses as a matter of routine especially of background High Energy Objects. The sky beyond MilkyWay should contain substantial numbers of lensed images.
     
  9. paddoboy Valued Senior Member

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    The point is the article is factual and based on observation. The SN being lensed is not directly behind the object doing the lensing, hence the time lapsed views expected of the same S/N due to light travelling different distances.
    If it was directly behind the object doing the lensing, we would have an Einstein ring, instead of an Einstein cross.

    see...............
    http://www.iflscience.com/space/gravitational-lens-allows-us-witness-supernova-repeat
    However, in 1964 Sjur Refsdal pointed out that different images of the same supernova would capture different moments in the explosion's evolution, and might be used to test the rate at which the universe is expanding. Great efforts have been made to find such an example of such a valuable case. Dr Patrick Kelly of the University of California, Berkeley was looking for distant galaxies and came across the sight of four images of a nine billion year old supernova around a galaxy in the MACS J1149.6+2223 cluster.

    “It really threw me for a loop when I spotted the four images surrounding the galaxy - it was a complete surprise,” Kelly says. The discovery has been announced in Science and named SN Refsdal.

    Refsdal was photographed from the November 3-20 last year, long enough to see one of the images, dubbed S3, brighten substantially, while the others showed no detectable change.
    http://www.iflscience.com/space/gravitational-lens-allows-us-witness-supernova-repeat


    Great article, great confirmation again of a prediction of GR, and extraordinarily lucky in being observed at this time.
     
    Last edited: Mar 10, 2015
  10. Trippy ALEA IACTA EST Staff Member

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    And this is kind of a key point that Wagner and Trivedi glossed over - we already have what they're talking about by observing the four different images we can see at this point. It's just a matter of measuring the light curves.
     
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  11. paddoboy Valued Senior Member

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    "Glossing over" is particularly common with "Trivedi" [Rajesh] in quite a few cosmology threads to date.
     
  12. RajeshTrivedi Valued Senior Member

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    Trippy,

    Nothing was glossed over, and nothing is being disputed here ! Paddo is as usual at his copy- paste best.

    .................around any asymmetrical lensing object can we not find a point (or a path) which will focus on the Earth (Observer), suggesting that we should see many more lenses as a matter of routine especially of background High Energy Objects. The sky beyond MilkyWay should contain substantial numbers of lensed images..........

    I see no controversy with above statement, this calls for discussions, rather than mundane appreciation like great article, great post, great confirmation.....thats silly beyond a point.
     
  13. CHRIS.Q Registered Senior Member

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    wooowwwwww
     
  14. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    I
    I 'glossed over' nothing. Yes, I acknowledged that there are four images of the same object. What I said was, and you apparently did not appreciate, was that one of the images shows a supernova. and one of the images is projected to show a supernova in a few years, and that when that happens, it will be highly unusual, as we will have confirmation of the supernova, that occured in 'one instant' in its own time frame, showing at varying times in our reference frame due to the varying path lengths for the four lensed images.
     
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  15. Trippy ALEA IACTA EST Staff Member

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    You've precisely illustrated my point - you're either ignoring the facts or haven't understood what you have read.

    There are two different versions of the same phenomenom going on here.
    First the image of the background galaxy is being lensed into four different locations by the MACS J1149.6+2223 cluster. The fact that we are seeing an image of the supernova at one location but not the other three is proof enough or Refsdale's prediction, however, there is icing to this cake.

    The image within which the supernova is currently visible is itself subjected to lensing by a galaxy within the MACS J1149.6+2223 cluster meaning that there are four images of the supernova in the huvvle shots in question, which are clearly visible in the image on the New York Times page I provided:

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    Here's an annotated image:

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    http://www.sci-news.com/astronomy/s...ur-magnified-images-same-supernova-02569.html

    One of those images was observed to brighten while the other three were not, offering further proof. That is what you're glossing over, ignoring, or otherwise failing to understand.
     
  16. paddoboy Valued Senior Member

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    Two glaring errors: [1] You certainly were glossing over the issue at hand, and [2] it was not my "copy n paste"....It was from Trippy's link.
    Try again.



    Like I said, great article and even further confirmation of standard GR and cosmology in general.
    Do you know what an Einstein cross is? or an Einstein ring?
    Perhaps if you google some respectable reputable site you may get the proper info.

    http://www.iflscience.com/space/gravitational-lens-allows-us-witness-supernova-repeat
    However, in 1964 Sjur Refsdal pointed out that different images of the same supernova would capture different moments in the explosion's evolution, and might be used to test the rate at which the universe is expanding. Great efforts have been made to find such an example of such a valuable case. Dr Patrick Kelly of the University of California, Berkeley was looking for distant galaxies and came across the sight of four images of a nine billion year old supernova around a galaxy in the MACS J1149.6+2223 cluster.

    “It really threw me for a loop when I spotted the four images surrounding the galaxy - it was a complete surprise,” Kelly says. The discovery has been announced in Science and named SN Refsdal.

    Refsdal was photographed from the November 3-20 last year, long enough to see one of the images, dubbed S3, brighten substantially, while the others showed no detectable change.
    http://www.iflscience.com/space/gravitational-lens-allows-us-witness-supernova-repeat
     
  17. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    From the images themselves: "may have appeared in 1995"; i.e. not observed then because it wasn't being looked for.; "may appear here in 2015-2020" the one that will take a longer transit distance, and thus a much later appearance by a few years. "observed in 2014"; four images of the same supernova, not showing in the other lensed images (with the quotes). I fully acknowledged all of that. What I said was that in 2015-2020 we should see that same supernova again flaring up. And that will be quite interesting. Yes, the four images in the 2014 image might have slightly different luminosities, which is interesting in itself, as they each have slightly different transit times; but the one in 2015-2020 (and I believe we'll be writing about that then, if we're lucky) should be the icing on the cake; which is what I said.
     
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  18. Trippy ALEA IACTA EST Staff Member

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    Read for comprehension:
    Look at the cutout in this annotated image:

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    There are four images of the galaxy.
    The supernova has been observed in one of those images, however, because of the proximity in the sky to a foreground galaxy, the image of the supernova has been lensed so that it appears four times around that foreground galaxy. That's what the four arrowed yellow dots are in the above image, shown un-annotated and zoomed in below:

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    Get it?

    The galaxy is lensed into four images by the fore-ground cluster.
    One of those lensed images of the background galaxy is further lensed by its proximity to a galaxy in the fore ground cluster to produce four images of the same supernova shown in the hubble images. It is one of these that has been observed to brighten without the corresponding brightening of the other three.
     
  19. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    That's exactly what I wrote. The other images of the galaxy don't show the supernova going off. One image does, because of additional lensing making the supernova show as four supernovas, with one of the images brightening more than the other 3. That's what I wrote. What I also wrote is that the icing on the cake will be when the image where the supernova doesn't yet show, goes of circa 2015-2020. It might even happen this year! Get it?
     
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  20. paddoboy Valued Senior Member

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    This is where you seemingly come undone Walter.
    The point is it is amazing, and to capture it should in time benefit cosmology and the knowledge we already have. As pointed out in the article, the different images of the same supernova would capture different moments in the explosion's evolution, and might be used to test the rate at which the universe is expanding...and taking into account recent finding by WMAP that this expansion is accelerating, the data gained from these images may yet prove invaluable.
    Plus being a standard candle S/N [type 1a] could further refine these measuring sticks for cosmological distances even further.
    Adding to that the obvious further confirmation re GR plus the opportunity to test it even further to greater degrees of precision.
    Why don't you find that more than "just Interesting"?

    From memory in past friendly banter with you, you did inform me that you also have a TOE? Apologies in advance if I have the wrong bloke. But if that is true, obviously you have an alternate proposal for GR that supercedes it, or at least other accepted areas of accepted cosmology.
    Naturally if what I say is true [that you did claim to have a TOE] then you would not be as receptive to the thought of GR being confirmed even further, so undermining yours and other alternative hypothesis.

    Yes, I certainly see this as possible ground breaking stuff once all data is received.
     
  21. paddoboy Valued Senior Member

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    That statement had me thinking.....especially the claim coming from a lay person like myself, who has no degree or phd or anything else other then a 12 months passing interest in cosmology. [his own words]
    So I thought I would check out just how easy and frequent such a occurrence would happen, considering that the duration of a S/N would be relatively short, although speaking universe wise, fairly common.

    http://physicsworld.com/cws/article...-creates-einsteins-cross-of-distant-supernova

    extracts from the article.....
    ""It's a wonderful discovery," says Alex Filippenko of the University of California, Berkeley, who is part of the team that found the latest quadruple-lensed supernova image, explaining that researchers have been "searching for a strongly lensed supernova for 50 years, and now we've found one". Thanks to the many conditions that need to be fulfilled for a gravitational lens to be seen from Earth, and the relatively short lifetime of a supernova, such a lensed supernova with four images has never been seen before"

    "Even more interesting, thanks to an understanding of the peculiarities of gravitational lensing, the team already knows that a fifth image will appear in the next decade. This will give astronomers a "replay" of the supernova, because light can take various paths around and through a gravitational lens and therefore arrive at Earth at different times. This is particularly rare and useful, because astronomy is not normally a predictive science. "The longer the pathlength, or the stronger the gravitational field through which the light moves, the greater the time delay," says Filippenko".

    The galaxy that splits the supernova's light is part of a large cluster – MACS J1149.6+2223 – that was discovered more than 10 years ago. In 2009 astronomers reported that the cluster created the largest known image of a spiral galaxy ever seen through a gravitational lens. The more distant galaxy appears in multiple images around the foreground lensing cluster and it hosts the supernova in one of the galaxy's spiral arms. "We get strong lensing by a red galaxy, but that galaxy is part of a cluster of galaxies, which is magnifying it more. So we have a double lensing system," explains Kelly.

    Kelly hopes that measuring the time delays between the phases of the supernova in the four images will let them put better constraints on the mass distribution of the foreground galaxies, as well as the expansion and geometry of the universe. If the researchers identify it as a Type Ia supernova (these have relatively standard brightness) by studying its spectrum, they could place even stronger limits on both the matter distribution and cosmological parameters.
    """"""""""""""""""""""""""""""""""""""""""""""""""

    So no, certainly not as a "matter of routine," substantial or as straight forward as some would like to suggest.
     
  22. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    It was very interesting the first time a lensing event was identified. Over time, as more and more became identified, they are less interesting. They all confirm the same thing.

    This one was different because it is 'double lensing', with one of the views showing four images of a supernova at slightly different (hours) stages of the explosion. That I found Interesting, but what one would expect for a four-image view, each having a few hours difference in transit time for the photons. I'm confident that this will be measured extensively over the next little while.

    What I will find to be even more interesting will be when the one that is projected to show the supernova appearing sometime between now and circa 2020. I would find that to be very interesting. It will provide us the opportunity, for the first time, to predict in advance when we should expect to 'see' a supernova before it actually is visible! That I find very interesting.

    Do you find that expected future event, in the next few days to years, to not be of interest? Or of less interest than an expected several hours variance in the four-image supernova we presently see/saw circa 2014? I have to presume we are still watching that region of the sky intensely, and the supernova in that galaxy image is no longer visible.
     
  23. paddoboy Valued Senior Member

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    They don't all confirm the same thing, and they have been searching for this type of event and alignment for 50 years. [see my link at post 18]
    How about the other possible data and knowledge that maybe extracted from this extraordinary event? Like the ability to test the rate at which the universe is expanding and any connection to the acceleration in that expansion rate....and the fact that the S/N being type 1a and a standard candle, possibilities of refinement in measuring distances etc....add to that the obvious further confirmation re GR plus the opportunity to test it even further to greater degrees of precision.
    These are some of the reasons why this serendipitous event is so important and note worthy. There are probably more that I'm not aware of and that are still being considered.
     

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