Starship Asterisk*

No X-rays from SN 2014J

Explanation: Last January, telescopes in observatories around planet Earth were eagerly used to watch the rise of SN 2014J, a bright supernova in nearby galaxy M82. Still, the most important observations may have been from orbit where the Chandra X-ray Observatory saw nothing. Identified as a Type Ia supernova, the explosion of SN2014J was thought to be triggered by the buildup of mass on a white dwarf star steadily accreting material from a companion star. That model predicts X-rays would be generated when the supernova blastwave struck the material left surrounding the white dwarf. But no X-rays were seen from the supernova. The mostly blank close-ups centered on the supernova's position are shown in the before and after inset panels of Chandra's false color X-ray image of the M82 galaxy. The stunning lack of X-rays from SN 2014J will require astronomers to explore other models to explain what triggers these cosmic explosions.

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Yeah, I sat there for a good few minutes saying to myself there's nothing there and wondering what it was I was supposed to look at before moving on to the reading part.

This is a different APOD, indeed. It doesn't feature the Moon, Mars, Saturn, Pluto or comet 67P/Churyumov–Gerasimenko. It doesn't show us Perseids, auroras, sunsets or awe-inspiring Earth weather. It doesn't show us an artist's illustration of an exoplanet. It doesn't show us a planetary nebula, a globular cluster or a galaxy.

It doesn't even show us a supernova.

It shows us what isn't there in a supernova remnant.

Wow! I love this APOD!

Supernovas type Ia are so incredibly important for today's cosmology, since they are "standard candles" that can be used as yardsticks (make that mega-light-year-sticks) to measure mindboggling distances in space. Supernovas type Ia can be used this way because their real luminosity can be inferred from the shape of their light curve. We have reason to think that these supernovas can be trusted, because their luminosity has been calibrated against other, fainter standard candles that we understand better, such as Cepheid variables. Yet we really don't understand the progenitors of Supernovas type Ia. Much of today's cosmology is built on the light curves of these supernovas, but astronomers don't really know what makes them go pop. Or at least not a single progenitor of such a supernova has been identified.

What today's APOD is telling us that SN 2014J, a type Ia supernova, wasn't caused by a white dwarf accreting matter from a swollen companion until the white dwarf underwent a runaway nuclear fusion process, leading to the explosive destruction of the white dwarf. This has been the most popular hypothesis to explain supernovas type Ia, but it didn't happen in the case of SN 2014J.

And that is what today's APOD is showing us. It is telling us what didn't happen to trigger SN 2014J, and it is telling us that the Chandra telescope and the people operating it has been able to prove this non-occurrence. It is also telling us that the painstaking work of astronomer-sleuths is really telling us something, but that there is so much work to be done, and still so much to know.

I love it!

Ann

I love it!

Ann

Wow Ann!

The glass is not half full. It is not half empty. It is OVERFLOWING with unanswered questions and expectations.

Thank you for pointing out just some of what I love about S.Asterisk*.

We have come a long way and still have a long way to go. Most of the fun in the trip is planning the trip. Now we must adjust the itinerary and continue on, over a detour across uncharted seas.

Bill

I've always been worried by the use of Type1as as a mega-light-year-stick as the theory relies on them not spinning much but trigger mechanism requires mass from a partner to fall in which would almost certainly lead to massive spin. This could, or course, mean that they are still within an order of magnitude of each other but its not hard to imagine one spinning so fast that its eventual detonation is a couple of orders of magnitude up on a non-rotating one.

Having said that I can imagine what this is to not produce xrays. Unless its a spinning white dwarf that finished eating its partner aeons ago and has just slowed enough to get the pressure to detonate and the debris expelled has yet to meet anything.

maybe it isn't a type la supernova. maybe its just a lazy red giant star breaking wind. or a compact star cluster that decided not to obey the laws set by earth's intelligent scientists. there are so many reasons to speculate about what sn 2014j is or is not. clearly this may be a case of the supernova that was not.
perhaps this is a good opportunity to ask questions about the goings on in m87 and elliptical galaxies in general - not that a supernova is related in any way to an elliptical galaxy. rather, it is an issue of 'the show must go on.'
question: why are elliptical galaxies yellowish in color. is the yellow color due to old yellow stars, or the result of intervening dust and gas enveloping the elliptic galaxy. why do elliptic galaxies lack a galactic ring formation (some elliptic galaxies do indeed have ring features but these are generally very compact and tightly wound).

mark twain once said something about conjecture and science

but, the hubble space telescope isn't about science - it is about ourselves

it is an instrument which the little green men on mars would envy

it is an instrument whose mission has just started - there are numerous additional deep field surveys which need to be made

which means that esa and nasa must take care that the telescope is in proper working condition

in general, what would be the physical conditions inside an elliptic galaxy - an artists rendering would be helpful

could we take another look at m87

Well, here I go making assumptions again. And I know this idea is pretty far out. But it might help to consider it before spending a lot of borrowed cash and big chunks of peoples lives trying to figure out why there are no x-rays from this event.
It seems OK to assume that everything has a beginning and an end, except maybe God, love and hate (enuf on that I hope)
So I will also assume the cycle of probably repeated 1a explosions occur at the cost of fairly constant dwindling mass of the donor companion.
At some point there should be an end to the donation of mass, no more gas.
Perhaps, in this one particular instance, the last little bit of donated mass acquired by the by the dwarf was just enough to set off the 1a. This would leave no remaining material spiraling in and therefore nothing for x-rays to be created with.

geckzilla wrote:Yeah, I sat there for a good few minutes saying to myself there's nothing there and wondering what it was I was supposed to look at before moving on to the reading part.

As Conan Doyle had Holmes say:

Gregory (Scotland Yard detective): "Is there any other point to which you would wish to draw my attention?"
Holmes: "To the curious incident of the dog in the night-time."
Gregory: "The dog did nothing in the night-time."
Holmes: "That was the curious incident.

Margarita

Here's the thing - there's *ALMOST* nothing there, but ... not quite.

Look at the "before" inset. There's a somewhat diffuse glow, strongest on the left, with something of a waist before it brightens back up just a bit (mostly reddish). There's also a somewhat more compact source in the upper left, reasonably bright.

Now, in the "after" inset, there's a brighter glow against the left edge, with almost no sign of that brighter reddish area near the bottom. And that compact source is much more muted. My guess: a molecular cloud of some kind, moving in from the right. Further characterization is left as an exercise for the professional astronomer.

So, it's not quite a dog that doesn't bark, as one that's muffled a bit.

Curiouser, and curiouser....

The Case of the Missing Xrays....
Sherlock Holmes and Watson are on the case!!!


Maybe not all Type1a supernova are alike....or maybe something "went wrong" with this one, or maybe it was a different phenomena...or maybe....just maybe.....a MESSAGE????? As some Ancient Astronaut Theorist believe....

:---[===] *

Tara_Li wrote:Here's the thing - there's *ALMOST* nothing there, but ... not quite.

Look at the "before" inset. There's a somewhat diffuse glow, strongest on the left, with something of a waist before it brightens back up just a bit (mostly reddish). There's also a somewhat more compact source in the upper left, reasonably bright.

Now, in the "after" inset, there's a brighter glow against the left edge, with almost no sign of that brighter reddish area near the bottom. And that compact source is much more muted. My guess: a molecular cloud of some kind, moving in from the right. Further characterization is left as an exercise for the professional astronomer.

So, it's not quite a dog that doesn't bark, as one that's muffled a bit.

I take astrophotography pictures. Even frames 1 second or less apart can be varied. Earth's Atmospheric conditions can distort things, and cause variations in the image....I KNOW...this is a SPACE TELESCOPE....no atmosphere...but I think there is probably just some camera, and light variations that can cause differences between images....especially DAYS, or Months apart....
I would say...the POST image....has better focus for example...

Just my take on it....

:---[===] *

It's not a good idea to try to do science with press release images.

The last link in the APOD text points to the Dark Energy Survey website. I've never visited that site before. After reading through their overview materials, I noted that in two places, they give the same explanation of red-shift:

This is known as redshift. Objects in space such as galaxies or exploding stars emit light in the form of light waves. As the light waves travels toward the earth over millions or billions of years, the universe continues to expand, lengthening the traveling waves as it does.

(I added the emphasis). I have not heard red-shift explained this way before. It does not sound at all like the explanations I have heard before, namely that we see red-shift because (at the time of emission), the light source was moving relative to the velocity we have (when receiving the light wave).

What is this new heresy?

MarkBour wrote:The last link in the APOD text points to the Dark Energy Survey website. I've never visited that site before. After reading through their overview materials, I noted that in two places, they give the same explanation of red-shift:

This is known as redshift. Objects in space such as galaxies or exploding stars emit light in the form of light waves. As the light waves travels toward the earth over millions or billions of years, the universe continues to expand, lengthening the traveling waves as it does.

(I added the emphasis). I have not heard red-shift explained this way before. It does not sound at all like the explanations I have heard before, namely that we see red-shift because (at the time of emission), the light source was moving relative to the velocity we have (when receiving the light wave).

What is this new heresy?

It is not a heresy at all. It has been known since the early 1930s that the universe is expanding. The farther away a luminous object is, the more its light is stretched on its way to us by the expansion of the universe. All really distant objects are redshifted due to the expansion of the universe. Nearby objects such as the Andromeda galaxy and even some galaxies in the Virgo Cluster can be blueshifted due to the fact that some of them are moving in our direction, and their own proper motion is enough to overcome the expansion of the nearby universe. Their net motion is in our direction, and the blueshift of these nearby galaxies is a Doppler shift.

But distant galaxies are always redshifted. Take a look at this picture of a distant cluster of galaxies, Abell 2744. Don't some of the galaxies in this cluster have a proper motion in our direction? Yes indeed, some of them do. Isn't their light blueshifted, then? No, because the galaxies are so far away that the expansion of the universe is carrying all these galaxies away from us, even those whose proper motion is in our direction. And therefore the light from all these galaxies is stretched by the expansion of the universe so that it becomes redshifted.

Ann

Boomer12k wrote:

Tara_Li wrote:Here's the thing - there's *ALMOST* nothing there, but ... not quite.

Look at the "before" inset. There's a somewhat diffuse glow, strongest on the left, with something of a waist before it brightens back up just a bit (mostly reddish). There's also a somewhat more compact source in the upper left, reasonably bright.

Now, in the "after" inset, there's a brighter glow against the left edge, with almost no sign of that brighter reddish area near the bottom. And that compact source is much more muted. My guess: a molecular cloud of some kind, moving in from the right. Further characterization is left as an exercise for the professional astronomer.

So, it's not quite a dog that doesn't bark, as one that's muffled a bit.

I take astrophotography pictures. Even frames 1 second or less apart can be varied. Earth's Atmospheric conditions can distort things, and cause variations in the image....I KNOW...this is a SPACE TELESCOPE....no atmosphere...but I think there is probably just some camera, and light variations that can cause differences between images....especially DAYS, or Months apart....
I would say...the POST image....has better focus for example...

Just my take on it....

:---[===] *

Fair enough. However, I would expect any imaging of a distant galaxy, even with the Chandra, would need a fair bit of exposure time to complete, and I would also expect the x-ray analog of the optics would be too fixed to be able to adjust focus. After all, for all intents and purposes, the objects are "at infinity". In addition, I would expect that the whole system, which has been running for quite some time, has been very thoroughly characterized and any predictable variations adjusted for.

seen this before elsewhere but not with as good as this explanation. Just when you think you have something figured out, here is another curve ball the Great Poobah must be having a gas with the puny humans.

MarkBour wrote:I have not heard red-shift explained this way before. It does not sound at all like the explanations I have heard before, namely that we see red-shift because (at the time of emission), the light source was moving relative to the velocity we have (when receiving the light wave).

Their are different mechanisms that can cause redshift. You're describing Doppler redshift. That is different from cosmological redshift, where space expands while the photon is traveling, and from gravitational redshift, where the wavelength of a photon increases as it climbs out of a gravitational well. Each of these is very similar with respect to observation, but described by somewhat different theory and math.

Chris Peterson wrote:

MarkBour wrote:I have not heard red-shift explained this way before. It does not sound at all like the explanations I have heard before, namely that we see red-shift because (at the time of emission), the light source was moving relative to the velocity we have (when receiving the light wave).

Their are different mechanisms that can cause redshift. You're describing Doppler redshift. That is different from cosmological redshift, where space expands while the photon is traveling, and from gravitational redshift, where the wavelength of a photon increases as it climbs out of a gravitational well. Each of these is very similar with respect to observation, but described by somewhat different theory and math.

My understanding was that all three arose from General Relativity, and were essentially the same underlying phenomena appearing in different manners. I'm just surprised quantum theory doesn't throw in its own red shift source. (Or does it? Do photons lose energy through interactions with the background vacuum fluctuations?)

Tara_Li wrote:My understanding was that all three arose from General Relativity, and were essentially the same underlying phenomena appearing in different manners. I'm just surprised quantum theory doesn't throw in its own red shift source. (Or does it? Do photons lose energy through interactions with the background vacuum fluctuations?)

The Doppler Effect is generally considered a classical phenomenon (which applies to other kinds of waves, like sound). The classical description only applies when v is much less than c. A full analysis requires the use of special relativity. Of course, most classical phenomena are only fully described using relativity.

Chris Peterson wrote:

Tara_Li wrote:My understanding was that all three arose from General Relativity, and were essentially the same underlying phenomena appearing in different manners. I'm just surprised quantum theory doesn't throw in its own red shift source. (Or does it? Do photons lose energy through interactions with the background vacuum fluctuations?)

The Doppler Effect is generally considered a classical phenomenon (which applies to other kinds of waves, like sound). The classical description only applies when v is much less than c. A full analysis requires the use of special relativity. Of course, most classical phenomena are only fully described using relativity.

And lately, the problem is whether you can describe it with both relativity and quantum theory.