APOD: X-ray Echoes from Circinus X-1 (2015 Aug 05)

[APOD Robot]

X-ray Echoes from Circinus X-1

Explanation: Circinus X-1 is an X-ray binary star known for its erratic variability. In the bizarre Circinus X-1 system, a dense neutron star, the collapsed remnant of a supernova explosion, orbits with a more ordinary stellar companion. Observations of the X-ray binary in months following an intense X-ray flare from the source in 2013 progressively revealed striking concentric rings - bright X-ray light echoes from four intervening clouds of interstellar dust. In this X-ray/optical composite, the swaths of Chandra Observatory X-ray image data showing partial outlines of the rings are in false colors. Remarkably, timing the X-ray echoes, along with known distances to the interstellar dust clouds, determines the formerly highly uncertain distance to Circinus X-1 itself to be 30,700 light-years.

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[Meekmoe]

Why the gap in the data?

[Ann]

It is fascinating that the X-ray echoes from Circinus X-1 made it possible to determine the distance to this X-ray binary. So what is the verdict, how bright is it at different wavelengths? I would love to know!

Click to view full size image

Source: http://phys.org/news/2013-12-blast-date ... inary.html

I found a fantastic picture of the evolution of Circinus X-1, and I can't resist posting it here. At the time of the mammoths on Earth, Circinus X-1 was just a binary star system, where one component was more massive than the other one. During the heyday of the civilization of ancient Greece, 2,500 years ago, the more massive component of Circinus X-1 exploded as a supernova. Nowadays this fascinating supernova remnant is being observed by the orbiting Chandra telescope. And a million years from now, Circinus X-1 will have faded as humanity leaves the Earth in starship Enterprise-like spaceships!

Ann

[geckzilla]

Why the gap in the data?

Chandra probably had other things to do. Takes a lot of observations to cover a relatively large part of the sky.

[henrystar]

Love to see the name "Circinus X-1" When I joined Herb Friedman's group of X-ray astronomers in 1967 there was great rivalry with Riccardo. Herb called his X-Ray sources "X-n" and Riccardo called his "XR-n". The race was won by Riccardo, and Herb didn't live long enough to share the Nobel Prize for X-ray astronomy. Oh, and yes, that is indeed an absolutely fascinating X-ray image!

[Boomer12k]

Fascinating...another form of Light Echo...AWESOME.

:---[===] *

[neufer]

[b][size=150][color=#0000FF]Circinus X-1[/color][/size][/b]

---

<<Circinus is a small faint constellation in the southern sky,
first defined in 1756 by French astronomer Nicolas Louis de Lacaille.

Its name is Latin for compass, referring to
the drafting tool used for drawing circles.>>

[bystander]

http://asterisk.apod.com/viewtopic.php?t=34903

[NGC3314]

Why the gap in the data?

Chandra's much-used ACIS instrument has 8 CCD detectors of two different kinds in adjacent arrays, one 2x2 square and one 4x1 optimized for dispersed spectra; each CCD covers a region about 8 arc minutes square. The break in the light echo in the released image composite is caused by the gap between two of these when the main X-ray target is put at the best compromise aim point. (This is mentioned briefly in the news release here). If the observers didn't know they would be looking for the echo at the time of observations planning this is what would have showed up (if they had known and waited better coverage, they could have specified offset telescope pointing or a dither pattern of continuous motion during the observations).

[BMAONE23]

The night sky would look much different to Superman or Ray Milland with their X-ray vision

[Ron-Astro Pharmacist]

I think the interstellar dust clouds turned Chandra into a kaleidoscope.

[geckzilla]

Why the gap in the data?

Chandra's much-used ACIS instrument has 8 CCD detectors of two different kinds in adjacent arrays, one 2x2 square and one 4x1 optimized for dispersed spectra; each CCD covers a region about 8 arc minutes square. The break in the light echo in the released image composite is caused by the gap between two of these when the main X-ray target is put at the best compromise aim point. (This is mentioned briefly in the news release here). If the observers didn't know they would be looking for the echo at the time of observations planning this is what would have showed up (if they had known and waited better coverage, they could have specified offset telescope pointing or a dither pattern of continuous motion during the observations).

I am very pleased that the people at Facebook are putting their noodles to work and figuring this out on their own. When I saw this image in the queue I was worried people would miss the point and just call it ugly or just remain confused instead of trying to work out why it looks like this. Maybe at some later point we can get a complete picture of it.

[BMAONE23]

I think the "Missing Info" creates a great contrast between the "Visual light Image" and the "X-Ray" component

[Mulsar]

I always assumed that a super nova was one of the most destructive forces in the universe. So the statement that the binary partner to the neutron star survived the explosion is a little confusing at least to me. I think we have seen how the force of super nova explosions can be directed in unusual ways. Is this what happened in this system with the force of the super nova being directed away from the binary partner leaving it mostly intact?

[Chris Peterson]

I always assumed that a super nova was one of the most destructive forces in the universe. So the statement that the binary partner to the neutron star survived the explosion is a little confusing at least to me. I think we have seen how the force of super nova explosions can be directed in unusual ways. Is this what happened in this system with the force of the super nova being directed away from the binary partner leaving it mostly intact?

A supernova is really only "destructive" to the star that explodes. A great deal of energy is released, but it falls off rapidly with distance (one over r squared). Planets in a system that goes supernova are likely to survive, still in orbit (although their orbits altered by the change in central mass). So there's no reason why a binary star system can't survive a supernova explosion, leaving behind the partner, now paired with a neutron star or black hole.

[puhbrox]

Wow that is simply beautiful. What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

[Chris Peterson]

Wow that is simply beautiful. What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.

A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.

[Meekmoe]

Why the gap in the data?

Thanks for the responses everyone! I hope my question didn't sound like I didn't appreciate the image. I was just curious if that data was not taken or if it was omitted and why. Chandra is one of my favorite telescopes due to the way it works with its concentric "mirrors" which only reflect because of its low glancing angles. I remember learning that they wanted to put more of the nested mirrors but couldn't because of weight restrictions. Still an amazing instrument!

[NGC3314]

I remember learning that they wanted to put more of the nested mirrors but couldn't because of weight restrictions. Still an amazing instrument!

At the field center, the mirror assembly delivers sharper images than any of the Chandra detectors can take full advantage of (tricks like subpixel reconstruction with the high-resolution imager come closest). This a legacy of one design iteration when it appeared Chandra would go to low orbit and servicing via shuttle would be possible, so they could contemplate replacing the detectors with newer ones. By the time it became clear that they would use the otherwise more-advantageous very high orbit it really went to, the mirrors had already been polished.

[puhbrox]

Wow that is simply beautiful. What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.

A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.

That is fascinating. Yea I bet it was scary! Seeing a new star appear during the day is unreal.

[neufer]

What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.

A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.

Egyptologists believe that the Great Pyramid of Giza was built as a tomb over a 10 to 20-year period concluding around 2560 BCE.

• But the first recorded supernova was by Chinese astronomers 1830 years ago
  [also in Circinus but much closer: 9,100 ly vs. 30,700 ly for Circinus X-1
  (; i.e., apparent magnitude -1.4 vs. -4)]:

[b][size=150][color=#0000FF]SN 185 (aka RCW 86)[/color][/size][/b]

---

<<SN 185 (aka RCW 86) was a supernova which appeared in the year AD 185, near the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA 14h 43m Dec −62° 30′, in Circinus. This "guest star" was observed by Chinese astronomers in the Book of Later Han, and might have been recorded in Roman literature. It remained visible in the night sky for eight months. This is believed to have been the first supernova recorded.

The gaseous shell RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes (larger than the apparent size of the full moon, which varies from 29 to 34 arc minutes). The distance to RCW 86 is estimated to be 2,800 parsecs (9,100 light-years). Recent X-ray studies show a good match for the expected age.

Differing modern interpretations of the Chinese records of the guest star have led to quite different suggestions for the astronomical mechanism behind the event, from a core-collapse supernova to a distant, slow-moving comet – with correspondingly wide-ranging estimates of its apparent visual magnitude (−8 to +4). The recent Chandra results suggest that it was most likely a Type Ia supernova (a type with consistent absolute magnitude), similar therefore to Tycho's star (which had apparent magnitude −4 at a similar distance).>>

[Guest]

"In the Constellation of Cygnus, there lurks...a mysterious invisible force."

This is not Cygnus X-1...

[geckzilla]

"In the Constellation of Cygnus, there lurks...a mysterious invisible force."

This is not Cygnus X-1...

Where do you see that at?

[neufer]

"In the Constellation of Cygnus, there lurks...a mysterious invisible force."

This is not Cygnus X-1...

Where do you see that at?

• http://tinyurl.com/oxo57ot