Astronomers observe a unique multiply-lensed supernova

January 19, 2016 by Tomasz Nowakowski report
The MACS J1149.6+2223 field, showing the positions of the three primary images of the SN Refsdal host galaxy (labeled 1.1, 1.2 and 1.3). SN Refsdal appears as four point sources in an Einstein Cross configuration in the southeast spiral arm of image 1.1. The highlighted box is shown at the same scale in panels on the right side, which illustrate the removal of contaminating diffraction spikes from a difference image. Each difference image is centered on the location of the contaminating star (top panel), then rotated clockwise by 90 degrees (middle panel). The rotated difference image is then subtracted from the initial difference image, removing most of the flux from the contaminating diffraction spike at the location of the SN Refsdal point sources (bottom panel). Credit: Steven A. Rodney et al., 2015.

(Phys.org)—SN Refsdal is a peculiar supernova visible within the field of the galaxy cluster MACS J1149+2223. Discovered in November 2014 using the Hubble Space Telescope, this supernova is the first that was seen multiple times thanks to gravitational lensing. Now, an international team of astronomers has published a paper on Jan. 15 summarizing one year of Hubble observations of SN Refsdal. The research is available online on the arXiv pre-print server.

More than a year ago, four images of SN Refsdal were detected by Hubble as part of the Grism Lens-Amplified Survey from Space (GLASS) program. GLASS acquires near-infrared grism spectra of massive galaxy clusters with the primary goals of studying faint, high-redshift galaxies and spatially resolved intermediate-redshift galaxies, as well as characterizing the cluster galaxy population. The images obtained by Hubble show SN Refsdal shining brightly from the arm of a spiral galaxy that lies far beyond another galaxy between the supernova and our planet. SN Refsdal as a background source is strongly lensed by galaxies and a galaxy cluster massive enough to bend the light into multiple images.

The astronomers then predicted that the supernova will soon reappear in the cluster field. Their predictions were correct, as SN Refsdal reappeared once more between mid November and Dec. 11, 2015. The exact date is uncertain by approximately one month, which is the interval between two consecutive Hubble observations.

This reappearance was a great occasion for a team of scientists led by Steven A. Rodney from the University of South Carolina to sum up the findings since previous sightings of SN Refdal in 2014. Moreover, the team managed to measure time delays for the four images obtained over a year ago.

The researchers found that the observed shape of SN Refsdal has distinct similarities with supernova SN 1987A. They also noted that the studied supernova is most likely a member of the peculiar Type II sub-class defined by the SN 1987A prototype.

To conduct precise measurements of relative time delays and also magnification ratios from the SN Refsdal data, the scientists used two methods: light curve template matching and flexible polynomial light curve models. They constructed their models based on supernovae like SN 1987A, which has a well-sampled light curve coverage. The researchers note that the use of two different methods yields complementary results.

"Even the best fit, template-based model shows systematic residuals and does not provide a good representation of the observed data. SN Refsdal is not quite a clone of other observed 87A-like Type II supernovae. Thus, as a second approach for measuring the time delays between the four Refsdal sources, we used a series of flexible light curve models—splines and polynomials—to represent the underlying light curve shape. By adopting these free-form curves in place of the rigid SN light curve templates, we can derive time delays that are agnostic about the classification of SN Refsdal," the astronomers wrote in the paper.

Rodney and his team determined these time delays with a precision of two to eight days. According to their study, the time delay between the first and the fourth image is about 26 days.

"This level of precision is promising, as it suggests that a similarly cadenced monitoring campaign could deliver a relative precision of 1 percent on the time delay to the next image," the paper reads.

SN Refsdal, as the first multiply-imaged supernova ever seen, will be a target of numerous observations conducted by scientists studying lens modeling methods. The researchers concluded that with a sufficiently rapid observational cadence and concerted lens modeling efforts, it will be feasible to use measurements of these lensed time delays as cosmographic tools. Cluster-lensed supernovae such as SN Refsdal could, indeed, contribute to future time delay cosmography efforts.

Explore further: New supernova remnant lights up

More information: SN Refsdal : Photometry and Time Delay Measurements of the First Einstein Cross Supernova, arXiv:1512.05734 [astro-ph.CO] arxiv.org/abs/1512.05734

Abstract
We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) 'Refsdal', a gravitationally lensed SN at z=1.488±0.001 with multiple images behind the galaxy cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1-S4) exhibited a slow rise (over ~150 days) to reach a broad peak brightness around 20 April, 2015. Using a set of light curve templates constructed from SN 1987A-like peculiar Type II SNe, we measure time delays for the four images relative to S1 of 4±4 (for S2), 2±5 (S3), and 24±7 days (S4). The measured magnification ratios relative to S1 are 1.15±0.05 (S2), 1.01±0.04 (S3), and 0.34±0.02 (S4). None of the template light curves fully captures the photometric behavior of SN Refsdal, so we also derive complementary measurements for these parameters using polynomials to represent the intrinsic light curve shape. These more flexible fits deliver fully consistent time delays of 7±2 (S2), 0.6±3 (S3), and 27±8 days (S4). The lensing magnification ratios are similarly consistent, measured as 1.17±0.02 (S2), 1.00±0.01 (S3), and 0.38±0.02 (S4). We compare these measurements against published predictions from lens models, and find that the majority of model predictions are in very good agreement with our measurements. Finally, we discuss avenues for future improvement of time delay measurements—both for SN Refsdal and for other strongly lensed SNe yet to come.

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Hat1208
4.1 / 5 (9) Jan 19, 2016
What is the EU's response to gravity lensing?
Vietvet
3.5 / 5 (16) Jan 19, 2016
What is the EU's response to gravity lensing?


Gravity is a Myth and Does Not Exist,
https://www.googl...0lensing
That's their bullshit story and they're sticking to it.
Hat1208
3.9 / 5 (7) Jan 19, 2016
@Vietvet

Thanks! Yeah I kind of thought that but I haven't seen an EU explanation for lensing that I can remember.
Mike_Massen
2.5 / 5 (13) Jan 19, 2016
Vietvet offered
What is the EU's response to gravity lensing?
Gravity is a Myth and Does Not Exist
https://www.googl...0lensing
That's their bullshit story and they're sticking to it
Thanks Vietvet :-)

At vid start, EU crowd betrays their fundamental philosophical problem with words to effect "nobody can prove & can't explain its cause", for that matter no-one can explain root cause of charge either !

FWIW Directed to the fringe who also bark re dark matter etc
Maths, inextricably linked to understanding of Physics, can describe well & predict very well too but, the EU crowd miss fundamental issue, Maths never seeks to actually explain as such & extended to Physics Eg Feynman's position when asked re magnetism, he honestly stated he doesn't know but, of course doesn't stop us using Maths/Physics to design motors, power systems, solenoids etc or gravity re satellites etc
cantdrive85
2.8 / 5 (11) Jan 19, 2016
That would be his bullshit story, clearly a misinformed soul. Gravity is alive an well in the Electric Universe, albeit in it's proper context.

https://www.youtu...iBxWieQU

And it is a fact that there is no physical mechanism for gravity in the mainstream view, other than the circular gravity explains gravity.

"There is no model of the theory of gravitation today, other than the mathematical form."
Feynman

Sorry to break up your strawman circle jerk of lies.
TechnoCreed
4 / 5 (12) Jan 19, 2016
Oh, a reply from the EU honorary clown!

"There is no model of the theory of gravitation today, other than the mathematical form."
Feynman
FYI GR is from Einstein.
Hat1208
4.3 / 5 (11) Jan 19, 2016
@cantdrive

What is the EU explanation of lensing?
Hat1208
4 / 5 (8) Jan 19, 2016
@TechnoCreed

I think cantdrive85 is the EU president.
Hat1208
4.5 / 5 (8) Jan 19, 2016
@cantdrive85

I thought this was a fairly straight forward question. What is the EU explanation for lensing?

TechnoCreed
3.9 / 5 (11) Jan 19, 2016
@TechnoCreed

I think cantdrive85 is the EU president.

It does not matter. The EU is a delusional Velikovskian cult. So they are all clown, just like Velikovsky was.
jonesdave
2.9 / 5 (12) Jan 19, 2016
Let's be honest: cantthink is an eejit. Along with all the other EU prats that drop in here. You'd think, after all this time, that they might have come up with something convincing. Not going to happen. Too uneducated for that. One of these days they will actually realise that they aren't very good at science. Hey Ho. Ever tried science, chaps?
jonesdave
2.3 / 5 (10) Jan 19, 2016
@TechnoCreed

I think cantdrive85 is the EU president.

It does not matter. The EU is a delusional Velikovskian cult. So they are all clown, just like Velikovsky was.


I have to improve on that. Velikovsky was not just a common or garden moron; he was a world class moron. End of story. Anybody believes that b*ll*cks needs a serious talking to!
jonesdave
2.6 / 5 (10) Jan 19, 2016
That would be his bullshit story, clearly a misinformed soul. Gravity is alive an well in the Electric Universe, albeit in it's proper context.

https://www.youtu...iBxWieQU

And it is a fact that there is no physical mechanism for gravity in the mainstream view, other than the circular gravity explains gravity.

"There is no model of the theory of gravitation today, other than the mathematical form."
Feynman

Sorry to break up your strawman circle jerk of lies.


Evidence, f*ckwit. Where is it? Are we waiting for Wal's latest pronouncement, by chance? Publish something, or shut the f*ck up. You've got sh*t. Not noticed yet? Let's see it in a decent journal, otherwise you've got sh*t. End of story.
Evidence-free pseudoscientific, cult-like, quasi-religious bollocks. Prove me wrong. Publish something.
plasmasrevenge
2.3 / 5 (6) Jan 19, 2016
This paper sounds too good to be true. Definitely expecting to see more successful predictions before buying into it, as should others.
plasmasrevenge
2.7 / 5 (7) Jan 19, 2016
Would like to take a moment to remind people of the existence of Google ...

Google: "electric universe gravitational lensing"

Works for me!
Solon
3.9 / 5 (7) Jan 19, 2016
Light bending by nonlinear electrodynamics under strong electric and magnetic field
http://arxiv.org/...33v5.pdf
plasmasrevenge
2 / 5 (8) Jan 20, 2016
It's fascinating that the more popular explanation involves the weakest force. I was under the impression that lensing frequently requires dark matter, due to gravity's weakness. If that's the case, then anybody who is pointing at lensing as some sort of proven phenomenon should be footnoting all of these claims with their assumptions; (2) are probably involved in some amount of circular logic; and (3) have certainly failed to rule out electromagnetism.

That said, I am always interested in accurate predictions, and would like to see more!
my2cts
3.7 / 5 (9) Jan 20, 2016
It's fascinating that the more popular explanation involves the weakest force. I was under the impression that lensing frequently requires dark matter, due to gravity's weakness. If that's the case, then anybody who is pointing at lensing as some sort of proven phenomenon should be footnoting all of these claims with their assumptions; (2) are probably involved in some amount of circular logic; and (3) have certainly failed to rule out electromagnetism.

That said, I am always interested in accurate predictions, and would like to see more!

In spite of the fact that the sun has at its surface a strong magnetic field, light bending by the sun is entirely explained by gravity.
EU is a waste of time, get real.
IMP-9
4.1 / 5 (9) Jan 20, 2016
Light bending by nonlinear electrodynamics under strong electric and magnetic field
http://arxiv.org/...5.pdfjCp


". In this paper, we consider the bending of a high energy photon"

It doesn't explain these results at optical energies.
bschott
2.1 / 5 (7) Jan 20, 2016
It doesn't explain these results at optical energies.


So you believe it's "easier" to bend the path of a high energy photon?

Evidence, f*ckwit. Where is it?


Ummmm....Dark Matter - Where is it?

Mechanism for faster than light expansion - Where is it?

Evidence that ALL light is redshifted due to spatial expansion - Where is it?

Quantum gravity - Where is it?

A working mainstream theory based on experimentally validated observations instead of assumptions and inferences - Where is it?

In spite of the fact that the sun has at its surface a strong magnetic field, light bending by the sun is entirely explained by gravity.


Nocents brain - Where is it?

bluehigh
2.3 / 5 (3) Jan 20, 2016
* In this paper, we consider the bending of a high energy photon * - Out of context,

This particular reference was to a photon with enough energy to travel close to a big sucker without get gobbled up.

Or more formally ...

"One example of light bending by an electrically charged object is when a high energy photon passes around a charged black hole with impact parameter greater than the Schwarzschild radius. "

The effect does indeed apply to less energetic photons.

Not that I believe it's the correct explanation but it's a step in the right direction, I suppose.

barakn
2.2 / 5 (5) Jan 20, 2016
The paper didn't mention the energy range of the photons, and the formulae used did not appear to be dependent on wavelength, energy, or frequency. I believe the implication is that the results apply to any photon whose wavelength is significantly smaller than the size of the object creating the electric or magnetic field, and since the objects discussed were black holes and neutron stars, this means a "high energy photon" is anything above the radio part of the spectrum, including the optical. So here I agree with bschott and against IMP-9.
TechnoCreed
3.7 / 5 (6) Jan 20, 2016
Light bending by nonlinear electrodynamics under strong electric and magnetic field
http://arxiv.org/...33v5.pdf


That is very surprising that Solon who, in his own words, present himself as "a Grumpy Old Instrument Engineer" and as a skeptic, would choose to bring here a paper on string theory. String theory did not prove much... so far. Here are the publications of M. Kim http://journals.a...22%7D%5D and M. Lee http://journals.a...22%7D%5D

Oh, and for bschott, sting theorists are those people that are working on quantum gravity.

Cont.
TechnoCreed
3.9 / 5 (7) Jan 20, 2016
...

In this paper they present a phenomenon that could hypothetically be observable when photons are passing close to a magnetar; not a very friendly place and not the kind of environment that one could recreate in a lab.

Anyway, it seems to me that nobody read the paper, because there is something clearly stated in the discussion at page 13.
Since the magnetic bending is expected to be small compared to gravitational bending any chance of observation may be realized only when the experiment detects the small variation over the gravitational bending. One way to observe the light bending by magnetic field may be using the birefringence...
Hum! I Know reading is hard for microcephals.
bschott
2 / 5 (4) Jan 20, 2016
Oh, and for bschott, sting theorists are those people that are working on quantum gravity.


It will really bolster their theory if it is ever observed then. Good luck string theorists!

Hum! I Know reading is hard for microcephals.


Ironically, observing light reacting to magnetic fields has several different names in Mainstream physics and there are several examples of it. Odd that the only instances where gravity appears to bend light are regions where there is also a magnetic field present.

A working mainstream theory based on experimentally validated observations instead of assumptions and inferences - Where is it?


Still waiting.....not holding breath.

IMP-9
5 / 5 (2) Jan 20, 2016
So you believe it's "easier" to bend the path of a high energy photon?


Yes, that's why the author takes care to note this. The mechanism uses is pair production. Note it doesn't really happen a low energies. This is because the probability of an optical photon at a few eV creating two 511 keV particles is quite small.

This particular reference was to a photon with enough energy to travel close to a big sucker without get gobbled up.


No. The Schwarzschild radius is independent of photon energy. Gravitational lensing is achromatic.
Phys1
4 / 5 (4) Jan 22, 2016
So you believe it's "easier" to bend the path of a high energy photon?


Yes, that's why the author takes care to note this. The mechanism uses is pair production. Note it doesn't really happen a low energies. This is because the probability of an optical photon at a few eV creating two 511 keV particles is quite small.

I don't see how virtual pair production would be of any influence here.

This particular reference was to a photon with enough energy to travel close to a big sucker without get gobbled up.


No. The Schwarzschild radius is independent of photon energy. Gravitational lensing is achromatic.

Agreed, but I see a conflict with your previous statement.

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