APOD: Cas A: Optical and X ray (2013 Jan 17)

[APOD Robot]

Cas A: Optical and X ray

Explanation: The aftermath of a cosmic cataclysm, supernova remnant Cassiopeia A (Cas A) is a comfortable 11,000 light-years away. Light from the Cas A supernova, the death explosion of a massive star, first reached Earth just 330 years ago. Still expanding, the explosion's debris cloud spans about 15 light-years near the center of this composite image. The scene combines color data of the starry field and fainter filaments of material at optical energies with image data from the orbiting NuSTAR X-ray telescope. Mapped to false colors, the X-ray data in blue hues trace the fragmented outer ring of the expanding shock wave, glowing at energies up to 10,000 times the energy of the optical photons.

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[bystander]

http://asterisk.apod.com/viewtopic.php?p=190593#p190593

[starsurfer]

I love seeing multiwavelength composites of interesting things that span quite a large part of the electromagnetic spectrum! However, I think this APOD would have been better if it showed the optical and the x-ray image was a mouseover, this would make comparion easier.

[Boomer12k]

In the bubble, top left part, it looks like a HAND, spraying energy to the right.

Awesome looking.

Strange stuff we see....stranger stuff we don't see.

:---[===] *

[orin stepanek]

Reminds me of lightning at the top of the remnant!

[Ken Crawford]

I love seeing multiwavelength composites of interesting things that span quite a large part of the electromagnetic spectrum! However, I think this APOD would have been better if it showed the optical and the x-ray image was a mouseover, this would make comparion easier.

That is a good idea, thanks! I will build one for my website at least

Kindest Regards,
Ken Crawford
http://www.imagingdeepsky.com

[rr_carroll]

Has a remnant been identified for Cas A?

[bethkatz]

I love seeing multiwavelength composites of interesting things that span quite a large part of the electromagnetic spectrum! However, I think this APOD would have been better if it showed the optical and the x-ray image was a mouseover, this would make comparion easier.

That is a good idea, thanks! I will build one for my website at least

Kindest Regards,
Ken Crawford
http://www.imagingdeepsky.com

Ken, thank you for both your answer above and sharing this splendid image.

It's a "pretty" picture. But it is much more interesting if you understand what it represents. I followed the "mapped to false colors" link to learn more about what range of the spectrum each color represents. I guess the orange color is the range between "red" toward "green".

It would be cool to see an overlay of blue, green, and red. I gather the "white" is a wide range.

[Ken Crawford]

Ken, thank you for both your answer above and sharing this splendid image.

It's a "pretty" picture. But it is much more interesting if you understand what it represents. I followed the "mapped to false colors" link to learn more about what range of the spectrum each color represents. I guess the orange color is the range between "red" toward "green".

It would be cool to see an overlay of blue, green, and red. I gather the "white" is a wide range.

When I saw the NASA image posted here released the first part of January, I saw they had overlaid the NuSTAR X-ray data on top of an optical image from the DSS. I took the NuSTAR data and overlaid it on top of my deep Cas A optical image that also had RGB star colors.

Here is a description from NASA on the NuSTAR X-ray data: Blue indicates the highest energy X-ray light, where NuSTAR has made the first resolved image ever of this source. Red and green show the lower end of NuSTAR's energy range, which overlaps with NASA's high-resolution Chandra X-ray Observatory.

I had time to throw together a mouse-over image showing my composite optical + X-ray and the optical without the X-ray data here: http://www.imagingdeepsky.com/Nebulae/C ... A_Xray.htm

Thanks again for the suggestion,
Kindest Regards,

Ken Crawford
http://www.imagingdeepsky.com

[bethkatz]

...
I had time to throw together a mouse-over image showing my composite optical + X-ray and the optical without the X-ray data here: http://www.imagingdeepsky.com/Nebulae/C ... A_Xray.htm

Thanks again for the suggestion,
Kindest Regards,

Ken Crawford
http://www.imagingdeepsky.com

Thank you. That's great.

Beth Katz

[revloren]

It looks like a special effect from the 60's Star Trek!

[Boomer12k]

I like the red emission nebula and the other reddish-bluish nebula to the left and right above the bubble. They look like flowers.

:---[===] *

[neufer]

Has a remnant been identified for Cas A?

This IS the remnant.

What has yet to be identified precisely is the (progenitor) supernova itself.

[b]A false color image composited of data from three sources. [color=#FF0000]Red is infrared data from the Spitzer Space Telescope,[/color] [color=#FF8000]orange is visible data from the Hubble Space Telescope[/color], and [color=#00A0A0]blue and green are data from the Chandra X-ray Observatory. The cyan dot just off-center is the remnant of the star's core.[/color][/b]

---

<<Cassiopeia A (Cas A) is a supernova remnant in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. It is believed that first light from the stellar explosion reached Earth approximately 300 years ago but there are no historical records of any sightings of the progenitor supernova, probably due to interstellar dust absorbing optical wavelength radiation before it reached Earth (although it is possible that it was recorded as a sixth magnitude star 3 Cassiopeiae by John Flamsteed on August 16, 1680). Possible explanations lean toward the idea that the source star was unusually massive and had previously ejected much of its outer layers. These outer layers would have cloaked the star and reabsorbed much of the light released as the inner star collapsed.

Calculations working back from the currently observed expansion point to an explosion that would have become visible on Earth around 1667. Astronomer William Ashworth and others have suggested that the Astronomer Royal John Flamsteed may have inadvertently observed the supernova on August 16, 1680, when he catalogued a star near its position. Another suggestion from recent cross-disciplinary research is that the supernova was the mythical "noon day star", observed in 1630, that heralded the birth of Charles II, the future monarch of Great Britain. At any rate, no supernova in the Milky Way has been visible to the naked eye from Earth since. Observations of the exploded star through the Hubble telescope have shown that, despite the original belief that the remnants were expanding in a uniform manner, there are high velocity outlying eject knots moving with transverse velocities of 5,500−14,500 km/s with the highest speeds occurring in two nearly opposing jets. When the view of the expanding star uses colors to differentiate materials of different chemical compositions, it shows that similar materials often remain gathered together in the remnants of the explosion.

Recently, an infrared echo of the Cassiopeia A explosion was observed on nearby gas clouds using Spitzer Space Telescope. The recorded spectrum proved the supernova was of Type IIb, meaning it resulted from the internal collapse and violent explosion of a massive star, most probably a red supergiant with a helium core which had lost almost all of its hydrogen envelope. This was the first observation of the infrared echo of a supernova which explosion had not been directly observed which opens up the possibility of studying and reconstructing past astronomical events.>>

[Chris Peterson]

This IS the remnant.

What has yet to be identified is the supernova itself.

Well, since the supernova is an event of the past, it never will be "identified", will it?

I'd say this is a remant- the remnant of the material thrown off by the supernova. But a supernova leaves another remnant as well- a black hole or neutron star. I rather expect that's the remnant the question was addressing.

[Gerry]

This image appears to have a lot of motion in it to me although I know it's a static image. Does anyone else experience this? I see motion in all the images that include points of light - slowly moving back and forth, up and down.

[theinnkeeper]

hey ive seen this on star trek tos

[Chris Peterson]

This image appears to have a lot of motion in it to me although I know it's a static image. Does anyone else experience this? I see motion in all the images that include points of light - slowly moving back and forth, up and down.

There are common optical illusions that can create that effect. It can also happen because of technological issues- if you are still using a CRT, for example, or even an LCD with a VGA connection. And there are also pathologies of the eye or brain - some minor, some major. If you commonly see motion in random dot fields, I'd advise a visit to an ophthalmologist. It's probably nothing serious, but it could be.

[vern]

I guess I am stupid. Please explane to me how an object that is 11,000 light-years away can have its light arrive on earth in only 330 years?

[Chris Peterson]

I guess I am stupid. Please explane to me how an object that is 11,000 light-years away can have its light arrive on earth in only 330 years?

The light of the supernova arrived at the earth 330 years ago. When it left the object (when the supernova "really" happened) isn't scientifically relevant, so isn't mentioned. It is customary to say that a supernova happened when it was observed, because that provides a stable and consistent time base that isn't dependent on the distance to the object (which is uncertain).

[Anthony Barreiro]

I guess I am stupid. Please explane to me how an object that is 11,000 light-years away can have its light arrive on earth in only 330 years?

The light of the supernova arrived at the earth 330 years ago. When it left the object (when the supernova "really" happened) isn't scientifically relevant, so isn't mentioned. It is customary to say that a supernova happened when it was observed, because that provides a stable and consistent time base that isn't dependent on the distance to the object (which is uncertain).

Vern, I've asked the same question myself. It's not a stupid question.

Astronomical distance (for instance this star is estimated to be 11,000 light years away) and the time span over which a supernova remnant develops (in this case we are seeing the remnant 330 years after the supernova explosion) are just two different frames of reference. If it helps, you can think of the supernova explosion as having happened 11,000 + 0 years ago, and the currently observed remnant happening now, 11,000 + 330 years after the explosion. But the 11,000 light year distance figure may change as we gain more information, and anyway, 0 years and 330 years are easier figures to work with. And if you're interested in understanding how supernova remnants develop over time, the fact that we're currently observing this one at 330 years old is the number you most care about.

(Rereading this, I see it's just a longer restatement of what Chris said, but I hope it helps anyway.)

[FloridaMike]

I guess I am stupid. Please explane to me how an object that is 11,000 light-years away can have its light arrive on earth in only 330 years?

The light of the supernova arrived at the earth 330 years ago. When it left the object (when the supernova "really" happened) isn't scientifically relevant, so isn't mentioned. It is customary to say that a supernova happened when it was observed, because that provides a stable and consistent time base that isn't dependent on the distance to the object (which is uncertain).

Vern, I've asked the same question myself. It's not a stupid question.

Astronomical distance (for instance this star is estimated to be 11,000 light years away) and the time span over which a supernova remnant develops (in this case we are seeing the remnant 330 years after the supernova explosion) are just two different frames of reference. If it helps, you can think of the supernova explosion as having happened 11,000 + 0 years ago, and the currently observed remnant happening now, 11,000 + 330 years after the explosion. But the 11,000 light year distance figure may change as we gain more information, and anyway, 0 years and 330 years are easier figures to work with. And if you're interested in understanding how supernova remnants develop over time, the fact that we're currently observing this one at 330 years old is the number you most care about.

(Rereading this, I see it's just a longer restatement of what Chris said, but I hope it helps anyway.)

Yes, it is a stupid question. If you read "Light from the Cas A supernova, the death explosion of a massive star, first reached Earth just 330 years ago" is worded in a a way to attempt to stifle just this sort of piddling question. I would rather read "Cas A supernova... occurred 330 years ago" but no, the editors contort the narrative to try to achieve clarity to no avail.

[Anthony Barreiro]

Yes, it is a stupid question. ... .

I believe that since apod is an educational presentation and starship asterisk is an educational forum, any sincere question can be an opportunity for learning. Since I am only an amateur with limited knowledge and a very basic conceptual framework, I could not in good conscience disdain "stupid" questions I myself asked not so long ago. If I hadn't asked them, and if kind people had not answered, I would know even less than I do. Honestly, I hope I never become so sophisticated that I start agreeing with people when they say, "this is probably a stupid question, but ..."

[Chris Peterson]

Honestly, I hope I never become so sophisticated that I start agreeing with people when they say, "this is probably a stupid question, but ..."

I don't think that attitude is the result of "sophistication".

[neufer]

Honestly, I hope I never become so sophisticated that I start agreeing with people when they say,
"this is probably a stupid question, but ..."

I don't think that attitude is the result of "sophistication".

<<Sophistication can link with concepts such as status, privilege and superiority. In social terms, sophistication can be seen as "a form of snobbery". In Ancient Greece, sophia was the special insight of poets and prophets. This then became the wisdom of philosophers such as sophists. But their use of rhetoric to win arguments gave sophistication a derogatory quality. The English regarded sophistication as decadent and deceptive until the aristocratic sensibilities and refined elegance of Regency dandies such as Beau Brummell (1778–1840) became fashionable and admired.>>

Sophisticate, v. t. [LL. sophisticatus, p.p. of sophisticare to sophisticate.] To render worthless by admixture; to adulterate; to damage; to pervert; as, to sophisticate wine.

• "To sophisticate the understanding." - Southey.
  
  "Yet Butler professes to stick to plain facts, not to sophisticate, not to refine." - M. Arnold.
  
  "They purchase but sophisticated ware." - Dryden.

...................................................................
Sophistry, n. [OE. sophistrie, OF. sophisterie.] Fallacious reasoning; reasoning sound in appearance only.
These men have obscured and confounded the nature of things by their false principles and wretched sophistry.

• "The juggle of sophistry consists, for the most part, in using a word in one sense in the premise,
  and in another sense in the conclusion." - Coleridge.

<<Sophism in the modern definition is a specious argument used for deceiving someone. In ancient Greece, sophists were a category of teachers who specialized in using the tools of philosophy and rhetoric for the purpose of teaching arete—excellence, or virtue—predominantly to young statesmen and nobility. The practice of charging money for education and providing wisdom only to those who could pay led to the condemnations made by Socrates, through Plato in his dialogues, as well as Xenophon's Memorabilia. Through works such as these, Sophists were portrayed as "specious" or "deceptive", hence the modern meaning of the term.

The term originated from Greek σόφισμα, sophisma, from σοφίζω, sophizo "I am wise"; confer σοφιστής, sophistēs, meaning "wise-ist, one who does wisdom," and σοφός, sophós means "wise man".>>

[starsurfer]

Ken, thank you for both your answer above and sharing this splendid image.

It's a "pretty" picture. But it is much more interesting if you understand what it represents. I followed the "mapped to false colors" link to learn more about what range of the spectrum each color represents. I guess the orange color is the range between "red" toward "green".

It would be cool to see an overlay of blue, green, and red. I gather the "white" is a wide range.

When I saw the NASA image posted here released the first part of January, I saw they had overlaid the NuSTAR X-ray data on top of an optical image from the DSS. I took the NuSTAR data and overlaid it on top of my deep Cas A optical image that also had RGB star colors.

Here is a description from NASA on the NuSTAR X-ray data: Blue indicates the highest energy X-ray light, where NuSTAR has made the first resolved image ever of this source. Red and green show the lower end of NuSTAR's energy range, which overlaps with NASA's high-resolution Chandra X-ray Observatory.

I had time to throw together a mouse-over image showing my composite optical + X-ray and the optical without the X-ray data here: http://www.imagingdeepsky.com/Nebulae/C ... A_Xray.htm

Thanks again for the suggestion,
Kindest Regards,

Ken Crawford
http://www.imagingdeepsky.com

I'm very happy that I inspired you in some way and the mouseover on your website is cool! My only suggestion would be to reverse it, the base image should be optical and the x-ray should be the mouseover, then you would get a greater sense of the x-ray shockwave of the supernova propagating outwards. The way you have it currently, it almost seems like watching it go backwards!

Also I would like to say that you are one of the very few people that expertly blend Ha and OIII with RGB! I would recommend doing more Ha and OIII images of really faint things, there are too many normal LRGB images of the same things. It's so nice to see an obscure and generally unknown object imaged! What inspired you to take an image of Cassiopeia A?

It would be great if you did decide to image some more obscure supernova remnants later this year, there must be so many others out there but the well known ones like the Crab Nebula, Veil Nebula and the Vela Supernova are usually the only ones that ever seem to receive any attention. One of my favourites is Puppis A, although this is a southern object and probably inaccessible from your observatory. Quite strangely, there are pretty much no optical images of Puppis A despite being bright enough to be imaged with conventional broadband filters. The only image I'm aware of is infrared, I would love to see a HaOIIIRGB composite of it! It also happens to be located in the sky next to the Vela Supernova! Both a closeup with a large telescope and a widefield that showed both together would be very interesting!