APOD: Light from Cygnus A (2015 Jan 24)

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APOD: Light from Cygnus A (2015 Jan 24)

Post by APOD Robot » Sat Jan 24, 2015 5:05 am

Image Light from Cygnus A

Explanation: Celebrating astronomy in this International Year of Light, the detailed image reveals spectacular active galaxy Cygnus A in light across the electromagnetic spectrum. Incorporating X-ray data (blue) from the orbiting Chandra Observatory, Cygnus A is seen to be a prodigious source of high energy x-rays. But it is actually more famous at the low energy end of the electromagnetic spectrum. One of the brightest celestial sources visible to radio telescopes, at 600 million light-years distant Cygnus A is the closest powerful radio galaxy. Radio emission (red) extends to either side along the same axis for nearly 300,000 light-years powered by jets of relativistic particles emanating from the galaxy's central supermassive black hole. Hot spots likely mark the ends of the jets impacting surrounding cool, dense material. Confined to yellow hues, optical wavelength data of the galaxy from Hubble and the surrounding field in the Digital Sky Survey complete a remarkable multiwavelength view.

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Ann » Sat Jan 24, 2015 5:17 am

Wow! There isn't a lot of the galaxy that can be seen in optical light compared with the X-rays and radio jets that it pumps out!

Can this galaxy be thought of as a monster version of M87? For example, is it thought to be more massive than M87? Does it have a bigger central black hole? And is it an elliptical galaxy like M87? (Yes... I guess it is. I don't think that galaxies with such incredibly active supermassive black holes can be anything but elliptical, at least not for any length of time.)

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by geckzilla » Sat Jan 24, 2015 5:20 am

The Chandra people are getting very good at bringing the whole electromagnetic spectrum into public awareness. There really isn't a better website to go see pictures of and learn to understand radio and x-ray light and how it comprises some very interesting structures in the Universe which can tell us a lot about how it works. I've been enjoying LIGHT: Beyond the Bulb quite a bit, as well.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by ta152h0 » Sat Jan 24, 2015 5:28 am

Just beautiful. Thank You !
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by bystander » Sat Jan 24, 2015 6:02 am

There are more images in Chandra's celebration of the International Year of Light:
http://asterisk.apod.com/viewtopic.php?t=34378
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Boomer12k » Sat Jan 24, 2015 9:02 am

It took me a while to find The Galaxy fore all the none visible stuff...just the tiny central light area... I had to go look at an image of the visible galaxy to get the perspective.....Awesome....it extends sooooo far.....

Active like a volcano...but in two dirctions....2 dimensionally speaking, of course...

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Boomer12k » Sat Jan 24, 2015 9:05 am

I look up at the night sky and ask.....what DON'T I see????

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Boomer12k » Sat Jan 24, 2015 9:29 am

The red ends, and hot spots, remind me of upper atmosphere "sprites"...you know for lightning....

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Cousin Ricky » Sat Jan 24, 2015 1:01 pm

APOD Robot wrote:One of the brightest celestial sources visible to radio telescopes, at 600 million light-years distant Cygnus A is the closest powerful radio galaxy.
Centaurus A is much closer than 600 million light years, and its radio jets are longer than 300,000 light years. Is Centaurus A not considered a “powerful” radio galaxy?

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Speculator » Sat Jan 24, 2015 4:31 pm

The galaxy appears to be travelling at a tremendous rate of speed through a medium of some sort .. that medium possibly Dark Matter.

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by rstevenson » Sat Jan 24, 2015 5:07 pm

Speculator wrote:The galaxy appears to be travelling at a tremendous rate of speed through a medium of some sort .. that medium possibly Dark Matter.
Cygnus A is travelling through space fairly fast relative to the other galaxies in its local cluster, but not at what I'd call a tremendous rate.

Dark Matter is not a medium, and the dark matter that is near Cygnus A could more properly be described as part of Cygnus A, just as dark matter in and around the Milky Way is part of the Milky Way.

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Guest » Sat Jan 24, 2015 5:48 pm

Composite of at least two optical images, as the dirctions of the flare spikes on the right side don't match those on the left.

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Chris Peterson » Sat Jan 24, 2015 5:54 pm

Cousin Ricky wrote:Centaurus A is much closer than 600 million light years, and its radio jets are longer than 300,000 light years. Is Centaurus A not considered a “powerful” radio galaxy?
Centaurus A is a low power radio galaxy (and isn't always called a radio galaxy at all). Its radio output is much less than that of Cygnus A.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by geckzilla » Sat Jan 24, 2015 6:38 pm

Guest wrote:Composite of at least two optical images, as the dirctions of the flare spikes on the right side don't match those on the left.
Hubble archive shows it was imaged several times using the WFPC2 and at no point did any single image cover the whole area. So it makes sense.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Chris Peterson » Sat Jan 24, 2015 6:46 pm

geckzilla wrote:
Guest wrote:Composite of at least two optical images, as the dirctions of the flare spikes on the right side don't match those on the left.
Hubble archive shows it was imaged several times using the WFPC2 and at no point did any single image cover the whole area. So it makes sense.
The references also say DSS data was used for the visible light components. That's actually photographic data! Not sure how it was used, but it offers more opportunities for different orientation of diffraction spikes.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by geckzilla » Sat Jan 24, 2015 7:01 pm

Chris Peterson wrote:
geckzilla wrote:
Guest wrote:Composite of at least two optical images, as the dirctions of the flare spikes on the right side don't match those on the left.
Hubble archive shows it was imaged several times using the WFPC2 and at no point did any single image cover the whole area. So it makes sense.
The references also say DSS data was used for the visible light components. That's actually photographic data! Not sure how it was used, but it offers more opportunities for different orientation of diffraction spikes.
I think that DSS reference may be a mistake in the text. I'm going to ask someone who should know. I've seen enough DSS data combined with Hubble data to know the difference when I see the two and all I see here are Hubble diffraction patterns.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Chris Peterson » Sat Jan 24, 2015 7:12 pm

geckzilla wrote:I think that DSS reference may be a mistake in the text. I'm going to ask someone who should know. I've seen enough DSS data combined with Hubble data to know the difference when I see the two and all I see here are Hubble diffraction patterns.
I wouldn't be surprised. My impression from a casual inspection of the image is that all the optical data came from the same camera (but not the same image). But it's possible there could be a little hole in some corner that got patched out of the DSS dataset, and is so minor as to be largely unnoticeable.
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by geckzilla » Sat Jan 24, 2015 7:17 pm

Chris Peterson wrote:
geckzilla wrote:I think that DSS reference may be a mistake in the text. I'm going to ask someone who should know. I've seen enough DSS data combined with Hubble data to know the difference when I see the two and all I see here are Hubble diffraction patterns.
I wouldn't be surprised. My impression from a casual inspection of the image is that all the optical data came from the same camera (but not the same image). But it's possible there could be a little hole in some corner that got patched out of the DSS dataset, and is so minor as to be largely unnoticeable.
I asked Joe DePasquale and he told me the black holes in the corners used to have some blurry DSS data included but then it was removed since it didn't improve the image. The text wasn't updated to reflect that (yet).
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by Speculator » Thu Jan 29, 2015 5:52 pm

rstevenson wrote:
Speculator wrote:The galaxy appears to be travelling at a tremendous rate of speed through a medium of some sort .. that medium possibly Dark Matter.
Cygnus A is travelling through space fairly fast relative to the other galaxies in its local cluster, but not at what I'd call a tremendous rate.

Dark Matter is not a medium, and the dark matter that is near Cygnus A could more properly be described as part of Cygnus A, just as dark matter in and around the Milky Way is part of the Milky Way.

Rob
Dark matter is not a medium, Rob? And yet it is said to make up 90% or whatever of the universe? Or perhaps you are sticking to one definition of the word 'Medium?'
Also, you seem to know an awful lot about Dark Matter considering it is not a proven anything just a possible theory of something.

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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by geckzilla » Thu Jan 29, 2015 5:58 pm

Speculator wrote:Dark matter is not a medium, Rob? And yet it is said to make up 90% or whatever of the universe? Or perhaps you are sticking to one definition of the word 'Medium?'
Also, you seem to know an awful lot about Dark Matter considering it is not a proven anything just a possible theory of something.
All we have are unproven possible theories of things. Everything is "just a theory" and to put the word "just" in front of is indicative of your ignorance about what a theory is. Are we going down this road?
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Re: APOD: Light from Cygnus A (2015 Jan 24)

Post by rstevenson » Thu Jan 29, 2015 6:04 pm

Speculator wrote:
rstevenson wrote:
Speculator wrote:The galaxy appears to be travelling at a tremendous rate of speed through a medium of some sort .. that medium possibly Dark Matter.
Cygnus A is travelling through space fairly fast relative to the other galaxies in its local cluster, but not at what I'd call a tremendous rate.

Dark Matter is not a medium, and the dark matter that is near Cygnus A could more properly be described as part of Cygnus A, just as dark matter in and around the Milky Way is part of the Milky Way.

Rob
Dark matter is not a medium, Rob? And yet it is said to make up 90% or whatever of the universe? Or perhaps you are sticking to one definition of the word 'Medium?'
Also, you seem to know an awful lot about Dark Matter considering it is not a proven anything just a possible theory of something.
When you talk about things moving through a medium, but what you describe as the medium -- in your case dark matter -- is actually part of what is moving, then yes, I think it's fair to say dark matter is not the medium you're talking about. (I should have said "the", not "a" medium in the first place. I would have made myself clearer.)

Dark matter is rather mysterious, true. But it is well supported by observations, so it has to be dealt with as a real thing -- unless, that is, you wish to subscribe to one of the alternate theories of gravitation, which are themselves a great deal less well supported than dark matter. In other words, if you incline to skepticism, be consistently skeptical.

Rob