Neutron star's echoes give astronomers a new measuring stick

Neutron star's echoes give astronomers a new measuring stick
Circinus X-1 is a bizarre and sometimes frenetic source of X-rays in our galaxy. Residing in the plane of the Milky Way, where it cannot be observed by optical telescopes because of obscuring clouds of interstellar dust, Circinus X-1 is the glowing husk of a binary star system that exploded in a supernova event just 2,500 years ago. It consists of a very dense neutron star locked in the orbital embrace of a companion star. The system is called an X-ray binary because it flashes in X-rays as material from the companion star is sucked onto the dense neutron star. Credit: NASA/Chandra X-ray Observatory

In late 2013, when the neutron star at the heart of one of our galaxy's oddest supernovae gave off a massive burst of X-rays, the resulting echoes—created when the X-rays bounced off clouds of dust in interstellar space—yielded a surprising new measuring stick for astronomers.

Circinus X-1 is a freak of the Milky Way. Located in the plane of the galaxy, Circinus X-1 is the glowing husk of a that exploded a mere 2,500 years ago. The system consists of a nebula and a neutron star, the incredibly dense collapsed core of the exploded star, still in the orbital embrace of its companion star.

The system is called an X-ray binary because it emits X-rays as material from the companion star spirals onto the much denser neutron star and is heated to very high temperatures.

"In late 2013, the neutron star underwent an enormous outburst for about two months, during which it became one of the brightest sources in the X-ray sky," explains University of Wisconsin-Madison astronomy Professor Sebastian Heinz. "Then it turned dark again."

The flicker of X-rays from the odd binary system was monitored by a detector aboard the International Space Station. Heinz and his colleagues quickly mounted a series of follow-up observations with the space-based Chandra and XMM-Newton telescopes to discover four bright rings of X-rays, like ripples in a cosmic pond, all around the neutron star at the heart of Circinus X-1.

Their observations were reported June 23 in The Astrophysical Journal.

The rings are light echoes from Circinus X-1's X-ray burst. Each of the four rings, says Heinz, indicates a dense cloud of dust between us and the supernova remnant. When X-rays encounter grains of dust in interstellar space they can be deflected, and if the dust clouds are dense they can scatter a noticeable fraction of the X-rays away from their original trajectory, putting them on a triangular path.

That phenomenon, Heinz and his colleagues recognized, could give astronomers an opportunity to use the geometry of the rings and a between deflected and undeflected X-rays to calculate the distance to Circinus X-1, a measurement previously unobtainable because the supernova is hidden in the dust that permeates the plane of our galaxy.

"We can use the geometry of the rings and the time delay to do X-ray tomography," Heinz explains. "Because the X-rays have traveled on a triangular path rather than a straight path, they take longer to get to us than the ones that were not scattered."

Combining those measurements with observations of the dust clouds by Australia's Mopra radio telescope, Heinz and his colleagues were able to determine which dust clouds were responsible for each of the four light echoes.

"Using this identification, we can determine the distance to the source accurately for the first time," according to the UW-Madison astronomer. "Distance measurements in astronomy are difficult, especially to sources like Circinus X-1, which are hidden in the plane of the galaxy behind a thick layer of dust—which makes it basically impossible to observe them with optical telescopes.

"In this case, we used the dust that otherwise gets in the way to pioneer a new method of estimating distances to X-ray sources," Heinz says.

Now astronomers know that Circinus X-1, one of the Milky Way's most bizarre objects, is 30,700 light-years from Earth.


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A blast from its past dates the youngest neutron-star binary

More information: arxiv.org/abs/1506.06142
Journal information: Astrophysical Journal

Citation: Neutron star's echoes give astronomers a new measuring stick (2015, June 23) retrieved 20 June 2019 from https://phys.org/news/2015-06-neutron-star-echoes-astronomers.html
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Jun 23, 2015
The star exploded 2,500 years ago but the distance to the star is 30,700 light years ago. Is their any discrepancy in these two numbers?

Not knocking the great math the astronomers used, just the difference in the two numbers.

Jun 23, 2015
OOPS sorry, tenstats The star exploded 2,500 years ago but the distance to the star is 30,700 light years ago. Is their any discrepancy in these two numbers?

Not knocking the great math the astronomers used, just the difference in the two numbers.

Read more at: http://phys.org/n...html#jCp

Jun 23, 2015
@NoTennisNow - there's no discrepancy in the astronomy.

If you want to be picky, it exploded 33,200 years ago and it is 30,700 years distance so we see it as it was 2500 years after exploding.

But astronomers often date something like a supernova using the reference frame of when its light reaches the earth rather than when the light was emitted. Before we knew how far away Circinus X-1 was, we knew that its light reached earth 2500 years ago, but we didn't know how long ago it 'actually' exploded. And distance measurements get refined - if the distance turns out to be 30,000 light years, the '2500 years ago' will still be valid but the '33,200 years ago' won't be.

Even if the exact distance were known, when measuring its size or its interaction with its surroundings it is simpler to use the reference frame of light arriving rather than having to constantly subtract 30,700 years because what we can measure is also delayed by the same 30,700 years.

Jun 24, 2015
Based off the picture my simple brain was hoping for gravity waves but the actual answer expands my horizons even further. This is so cool. "Tomography" is on my Wikipedia list for today!

Jun 25, 2015
OK. But the text states "Circinus X-1 is a freak of the Milky Way. Located in the plane of the galaxy, Circinus X-1 is the glowing husk of a binary star system that exploded a mere 2,500 years ago."

I just have problems with "we knew".

Putting this aside, are the astronomers viewing the remnants of the explosions?


Jun 25, 2015
@Ren82:
I know well the claims and theories of official cosmology
"Official cosmology" is a strawman of your own creation; it does not exist
There is almost nothing certain in this science with few exceptions
Likewise, this "certainty" you seek does not exist, in the fields of astronomy, astrophyics, and cosmology. Indeed, given its inductive nature, no such certainly exists in science. Period.
You talk about models and hypotheses. What says electromagnetic wave coming from cosmic space?
Models and hypotheses (m&h, and theories and data) is all there is. "electromagnetic wave coming from cosmic space" is also just m&h; data is bits from detectors ... You will forever seek in vain; science - not even lab chemistry - does not deal with "prove" or "proof" (that's the realm of mathematics).

Time to leave 'lies to children' behind?

Thank you, JT, for succinctly showing Ren his error...

Jun 25, 2015
@NoTennisNow:

To be precise it should state "Circinus X-1 is a freak of the Milky Way. Located in the plane of the galaxy, Circinus X-1 is the glowing husk of a binary star system that exploded so recently that light from the explosion reached us a mere 2,500 years ago."

But that is much wordier, and since the convention for distant things where the only effects we detect propegate at the speed of light is to use the reference frame of when those effects are detectable at earth, astronomers usually use the shorter version.

As the age, for many recent supernovae in our galaxy we can compare pictures from dozens or even a hundred years ago and measure the radial expansion and determine quite accurately how long ago the diameter (as it appeared from earth) would have been zero.

However in the case of Circinus X-1 we only recently obtained detailed images, so the age (even as seen from earth) is not as well known.


Jun 26, 2015
@JeanTate

Is it difficult for you to be clear and concise? I asked whether there is evidence for the existence of neutron stars as is defined by official cosmology which stands behind the metaphysical theory of the big bang and which is taught in universities. Yes or no? The same question for the fictional black holes.

@Jeantate,
Ren will never believe provided evidence. His MO is to find vague ways of questioning it and consider that as proof that evidence is faulty. He WANTS it to be inexplicable "magic"... His motivation for this is his inability to actually comprehend the available data...
He will not accept ANY other explanation other than the one he has arrived at...

Jun 29, 2015
@WG .. Your attacking the man ( Ren82 ). That's often my failing. You, my autistic bourbon sipper, I understood were more likely to be open to alternative views.

Are you concerned that by sitting on the fence, you might get shot by a peace keeping force? Peer pressure perhaps?

* Offers WG a comfy chair and a double Wild Turkey *

Think.


Jun 29, 2015
@WG .. Your attacking the man ( Ren82 ). That's often my failing. You, my autistic bourbon sipper, I understood were more likely to be open to alternative views.

* Offers WG a comfy chair and a double Wild Turkey *

It was an observation, BH. If I were to provide empirical evidence that a god existed, he would not believe it. He considers anything unknowable to be the dominion of a higher being, therefore wishing any thing outside of our immediate needs to be "unknowable". It is not an alternative view. Rather, self imposed blinders...

Jun 30, 2015

Cocks are ticking with slightly different rates


Ren where's your mate Stimpy? Haven't you got some twisted adventure to be going on?

Jun 30, 2015
Cocks are ticking with slightly different rates because we can not produce exactly the same clocks and repeat the same conditions in which working these clocks.

If it were like this then we would see a random distribution when we take one clock higher than the other. But we don't. We always see the clock that is higher ticking faster.

Clocks are checked against one another while on the ground (to make sure that they run at the same speed). The 'ticking' is based on count of very stable (quantized) natural processes.
https://en.wikipe...ic_clock

We are not talking mechanical clockwork, here.

GPS system always gives errors within a few meters, and apparently none of these corrections can not ensure better accuracy.

There are errors because not everything is accounted for in the GPS model.
https://en.wikipe...urveying

Jun 30, 2015
If such kind of experiments gave convincing evidence for the validity of GR, researchers will not make attempt with four gyroscope positioned in space around the Earth.

Your arguments are inconsistent. There is no such thing as a 'final' theory.

We have to occasionally test our assumptions. That's good scientific practice. The aim is to test it from as many angles as we can think of. Always with the HOPE that we find something wrong with it - because that is the tiny piece we need in order to make better physical theories.
Currently GR has withstood all tests thrown at it. Which means it's a very, very good theory (or we're just too dumb to think of more telling tests).

Which is nice (we can trust stuff we build upon it-like GPS), but also vexing (we have no new leads where to look for a better theory).

Jun 30, 2015
@WG

It was an observation .. Ok fair enough though unnecessary. His views are well known, some agree some don't. Why force?

Out of my comfort zone, quite some years ago enjoying company, I joined in a few art classes. One of the cognitive changes that stuck was that the idea of 'I know what I like' does Not define a good artwork. The use of technique and intent to convey emotion and much more requires appreciation.

Sometimes I wonder if the same depth of 'knowing' what the artist is 'conveying' applies to those 'outside' the 'mainstream' of scientific endeavour.

Don't know if I have a point.

* tops up the bourbon and offers pretzels *

Jun 30, 2015
@WG
It was an observation .. Ok fair enough though unnecessary. His views are well known, some agree some don't. Why force?

Was just pointing out to Jean the nature of his annoying MO.

Out of my comfort zone, quite some years ago enjoying company, I joined in a few art classes. One of the cognitive changes that stuck was that the idea of 'I know what I like' does Not define a good artwork. The use of technique and intent to convey emotion and much more requires appreciation.

Some art requires no emotional engagement, just aesthetic acknowledgement...

Don't know if I have a point.

Was relative to you for whatever reason.

* tops up the bourbon and offers pretzels *

accepts...:-)


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