APOD: Jets from Unusual Galaxy Centaurus A (2021 Jan 17)

[APOD Robot]

Jets from Unusual Galaxy Centaurus A

Explanation: The jets emanating from Centaurus A are over a million light years long. These jets of streaming plasma, expelled by a giant black hole in the center of this spiral galaxy, light up this composite image of Cen A. Exactly how the central black hole expels infalling matter remains unknown. After clearing the galaxy, however, the jets inflate large radio bubbles that likely glow for millions of years. If energized by a passing gas cloud, the radio bubbles can even light up again after billions of years. X-ray light is depicted in the featured composite image in blue, while microwave light is colored orange. The base of the jet in radio light shows details of the innermost light year of the central jet.

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[Ann]

APOD Robot wrote:

These jets of streaming plasma, expelled by a giant black hole in the center of this spiral galaxy, light up this composite image of Cen A.

Wikipedia wrote:

There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type (lenticular galaxy or a giant elliptical galaxy)...

I'd say that Cen A is a large (but not overwhelmingly large) elliptical (or possibly lenticular) galaxy that has collided with, and is in the process of ingesting, a smaller spiral galaxy.

Centaurus A in optical light. Photo: ESO.

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PerA_optical_registered.jpg

Perseus A in optical light. Photo: R. Jay GaBany.

More or less the same thing that has happened to Centaurus A, the collision with a small spiral galaxy and the tremendous outbursts and jets following this galactic meal, has happened to another giant elliptical galaxy, Perseus A. But the ingestion and shredding of the intruding spiral galaxy has gone farther in Perseus A than in Centaurus A.

An accumulation of 270 hours of Chandra observations of the central regions of the Perseus galaxy cluster reveals evidence of the turmoil that has wracked the cluster for hundreds of millions of years. The dark blue filaments in the center are likely due to a galaxy that has been torn apart and is falling into NGC 1275, a.k.a. Perseus A, the giant galaxy that lies at the center of the cluster. Photo: NASA/CXC/IoA/A.Fabian et al.

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Wikipedia wrote:

In 2003 a team of astronomers led by Dr. Andrew Fabian at Cambridge University discovered one of the deepest notes ever detected, after 53 hours of Chandra observations. No human will actually hear the note, because its time period between oscillations is 9.6 million years, which is 57 octaves below the keys in the middle of a piano. The sound waves appear to be generated by the inflation of bubbles of relativistic plasma by the central active galactic nucleus in NGC 1275. The bubbles are visible as ripples in the X-ray band since the X-ray brightness of the intracluster medium that fills the cluster is strongly dependent on the density of the plasma.

Just maybe this is what is happening (or what is going to happen in the future) to Centaurus A, although almost certainly on a smaller scale.

Astronomers found that Hanny's Voorwerp is the only visible part of a 300,000-light-year-long gaseous streamer stretching around galaxy IC 2497. The greenish Voorwerp is visible because a searchlight beam of light from the galaxy's core illuminated it. This beam came from a quasar, a bright, energetic object that is powered by a black hole. An encounter with another galaxy may have fed the black hole and pulled the gaseous streamer from IC 2497.

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And for good measure, let's look at this series of Hubble images of how galaxy collisions may feed gas into a large galaxy's central black hole, turning it (at least temporarily) into a quasar that is emitting brilliant light, and probably also jets.

Ann

[orin stepanek]

Nasty looking image! I don't think it would be a good place to live!
It looks as though the whole galaxy is in chaos!! Beautiful though; isn't it?

CenAjets_EsoNasa_960.jpg

[neufer]

<<The Perseus cluster (Abell 426) is a cluster of galaxies in the constellation Perseus. It has a recession speed of 5,366 km/s and a diameter of 863′. It is one of the most massive objects in the known universe, containing thousands of galaxies immersed in a vast cloud of multimillion-degree gas.>>

Teacher says, every time Abell 426 rings an angel gets his wings:
https://en.wikipedia.org/wiki/Angel#/me ... sko_01.JPG

Chandra observations of the central regions of the Perseus galaxy cluster reveals evidence of the turmoil that has wracked the cluster for hundreds of millions of years. The dark blue filaments in the center are likely due to a galaxy that has been torn apart and is falling into NGC 1275, a.k.a. Perseus A, the giant galaxy that lies at the center of the cluster. Photo: NASA/CXC/IoA/A.Fabian et al.

---

In 2003 a team of astronomers led by Dr. Andrew Fabian at Cambridge University discovered one of the deepest notes ever detected, after 53 hours of Chandra observations. No human will actually hear the note, because its time period between oscillations is 9.6 million years, which is 57 octaves below the keys in the middle of a piano. The sound waves appear to be generated by the inflation of bubbles of relativistic plasma by the central active galactic nucleus in NGC 1275. The bubbles are visible as ripples in the X-ray band since the X-ray brightness of the intracluster medium that fills the cluster is strongly dependent on the density of the plasma.

Just maybe this is what is happening (or what is going to happen in the future) to Centaurus A, although almost certainly on a smaller scale.

[johnnydeep]

Nasty looking image! I don't think it would be a good place to live!
It looks as though the whole galaxy is in chaos!! Beautiful though; isn't it?

It's not at all clear to me how deadly this black hole activity and consequent plasma jets and x-ray emission and bubbles of radio emitting gas would be to potential life. Certainly radio waves aren't deadly, right? I think it looks a lot worse than it really is. Surely there are plenty of star systems in Centaurus A with planets that are just as hospitable to life as mother Earth?

[Ann]

Teacher says, every time Abell 426 rings an angel gets his wings:
https://en.wikipedia.org/wiki/Angel#/me ... sko_01.JPG

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Every time a an angel does its job on the Earth and therefore wins its wings, a bell rings. Even if his name is Clarence.

So don't ask for whom the bell tolls; it tolls for Clarence. Or someone like him.

Even if it tolls 57 octaves below the keys in the middle of a piano.

Ann

[orin stepanek]

Nasty looking image! I don't think it would be a good place to live!
It looks as though the whole galaxy is in chaos!! Beautiful though; isn't it?

It's not at all clear to me how deadly this black hole activity and consequent plasma jets and x-ray emission and bubbles of radio emitting gas would be to potential life. Certainly radio waves aren't deadly, right. I think it looks a lot worse than it really is. Surely there are plenty of star systems with planets that just as hospitable to life as mother Earth?

Ya; I see it looks a lot like your Avatar! That is a pretty good sized jet though!

[neufer]

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Click to play embedded YouTube video.

Teacher says, every time Abell 426 rings an angel gets his wings:

https://en.wikipedia.org/wiki/Angel#/me ... sko_01.JPG

Every time a an angel does its job on the Earth
and therefore wins its wings, a bell rings.

Even if his name is Clarence.

So don't ask for whom the bell tolls; it tolls for Clarence.

Even if it tolls 57 octaves below the keys in the middle of a piano.

Ann, an Angel fledging every 9.6 million years is not very useful.

Better a Clown pratfalling every time the Zu-zu rag plays.

(Are those Zuzu's petals emanating from Centaurus A )

<<Zu Zu Ginger Snaps were round drop cookies produced beginning in 1901 by National Biscuit Company (NBC) – later changed to Nabisco – until the early 1980s. The snaps were "a spicy combination of ginger and sugar-cane molasses" and came in a distinctive yellow box with reddish type.

The mascot was the Zu Zu Clown. The Clown became central to an advertising campaign which included ads, signs, free clown costumes for children and two sizes of clown dolls.

In the movie It´s A Wonderful Life by Frank Capra, one of George Bailey's daughters is named Zu Zu after these cookies. Near the end of the film, when her dad rushes up the stairs and Zuzu greets him, he replies "Zuzu, my little ginger snap!"

Title: Zu-zu rag
Composer/Lyricist: by Max E. Fishler ; [arr. by Hector MacCarthy].
Publication: New York : John Franklin, c1916.
Description: 5 p. of music ; 35 cm.
Collection: Rag

[VictorBorun]

Jets from Unusual Galaxy Centaurus A

It's easy to guess disk's plane angle to our line of sight.
But what about the pair of jets?
The visible one must be toward us. But exactly how toward-us it is?

There is a faint false-red radio sphere of obvious size.
It's tempting to guess that the plumes at the end of the jets are inscribed in that shere. But what can we know?

[Ann]

Jets from Unusual Galaxy Centaurus A

It's easy to guess disk's plane angle to our line of sight.
But what about the pair of jets?
The visible one must be toward us. But exactly how toward-us it is?

There is a faint false-red radio sphere of obvious size.
It's tempting to guess that the plumes at the end of the jets are inscribed in that shere. But what can we know?

I recommend the Wikipedia page on Centaurus A. There is a lot of useful information there.

You are indeed right that the red lobe that is seen to contain a jet is the one that is closest to us. The jet and the lobe are not directed straight at us, however. If they were, we wouldn't see a jet at all, just a very bright central light source.

Ann

[VictorBorun]

The jet and the lobe are not directed straight at us, however. If they were, we wouldn't see a jet at all, just a very bright central light source.
Ann

For M87 the angle between our line of site and the axis of the jet and the counterjet: 17±3°.
(using apparent component speeds in the jet, 0.21±0.04, and the counterjet, 0.14±0.02$, along with an intensity ratio, 9.5±1.5
https://iopscience.iop.org/article/10.3 ... 357/aaafcc).
17°is a small angle I would never have guessed. But that's what they calculate for the counterjet to be almost invisible.

It seems Centaurus A's jets are almost in the plane of the dust gas disk. Does it show that the black hole originates from another galaxy?

[Ann]

The jet and the lobe are not directed straight at us, however. If they were, we wouldn't see a jet at all, just a very bright central light source.
Ann

For M87 the angle between our line of site and the axis of the jet and the counterjet: 17±3°.
(using apparent component speeds in the jet, 0.21±0.04, and the counterjet, 0.14±0.02$, along with an intensity ratio, 9.5±1.5
https://iopscience.iop.org/article/10.3 ... 357/aaafcc).
17°is a small angle I would never have guessed. But that's what they calculate for the counterjet to be almost invisible.

It seems Centaurus A's jets are almost in the plane of the dust gas disk. Does it show that the black hole originates from another galaxy?

This is how I understand it. Centaurus A consists of two colliding galaxies, one larger elliptical galaxy and one smaller spiral galaxy which is being incorporated into the larger elliptical. (Or, okay, we may describe Cen A as one galaxy, but it definitely has two components.)

I'd say that the large elliptical galaxy definitely has a central black hole, and it had that black hole before the galaxy collided with the spiral. The collision has undoubtedly sent a large amount of gas into the black hole of the elliptical galaxy, and this copious sudden gas influx is what has made the black hole of the elliptical galaxy act up and spew out jets.

An interesting question is whether or not the spiral galaxy has a sizable black hole of its own. It may have one, but it also may not. Small local spiral galaxy M33 doesn't have a central black hole, at least not one that can be described as "supermassive" in any way.

But if the spiral galaxy that is colliding with the elliptical galaxy in what is Centaurus A does have a supermassive black hole, it would be interesting to see what would happen if the black holes were to collide. I guess that chances are slim that that would happen, provided the small spiral galaxy has a supermassive central black hole in the first place.

Ann

[johnnydeep]

Jets from Unusual Galaxy Centaurus A

It's easy to guess disk's plane angle to our line of sight.
But what about the pair of jets?
The visible one must be toward us. But exactly how toward-us it is?

There is a faint false-red radio sphere of obvious size.
It's tempting to guess that the plumes at the end of the jets are inscribed in that shere. But what can we know?

Based solely on its crisp edges, that "faint red sphere" in your pic has got to be an imaging artifact. It almost seems like it simply marks the edge of the detector.

[johnnydeep]

The jet and the lobe are not directed straight at us, however. If they were, we wouldn't see a jet at all, just a very bright central light source.
Ann

For M87 the angle between our line of site and the axis of the jet and the counterjet: 17±3°.
(using apparent component speeds in the jet, 0.21±0.04, and the counterjet, 0.14±0.02$, along with an intensity ratio, 9.5±1.5
https://iopscience.iop.org/article/10.3 ... 357/aaafcc).
17°is a small angle I would never have guessed. But that's what they calculate for the counterjet to be almost invisible.

It seems Centaurus A's jets are almost in the plane of the dust gas disk. Does it show that the black hole originates from another galaxy?

Huh? To me it looks like the jets are almost perpendicular to the plane of the dust disk (actually, more like 45 degrees from perpendicular!). Is that what you mean or am I missing your point entirely?

[neufer]

Click to play embedded YouTube video.

NGC 5128 was discovered by James Dunlop in 1826

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[VictorBorun]

To me it looks like the jets are like 45 degrees from perpendicular!

1) The jet and the counterjet line can't lie in the plane of the picture because the counterjet seems much paler than the jet and so must be flowing away from us.
2) The dust gas disk galaxy can't lie in the plane of the picture because the dusty band looks not like a ring but rather like a narrow strip.

I think the core of dust gas disk is behind the dusty rim and somewhat lower and to the right,
and the jet is flowing mostly toward us and somewhat up and to the left.
And that makes its near-core part almost lie in the plane of the disk and only the outer 9/10 of that jet we can see coming from behind the dust gas disk.

Its orange plume is an arc mostly along our line of sight and seems the size of the dust gas disk while the real size of the plume is 10 times larger.

[VictorBorun]

An interesting question is whether or not the spiral galaxy has a sizable black hole of its own. It may have one, but it also may not. Small local spiral galaxy M33 doesn't have a central black hole, at least not one that can be described as "supermassive" in any way.

But if the spiral galaxy that is colliding with the elliptical galaxy in what is Centaurus A does have a supermassive black hole, it would be interesting to see what would happen if the black holes were to collide. I guess that chances are slim that that would happen, provided the small spiral galaxy has a supermassive central black hole in the first place.

If they are to merge tomorrow minus the delay then we are not ready to listen to the low frequency gravitation waves.
The large BHs would not spiral down fast enough

[VictorBorun]

Click to view full size image

NGC 5128 was discovered by James Dunlop in 1826

James Dunlop & and his rubber tire galaxy

[Ann]

Click to view full size image

NGC 5128 was discovered by James Dunlop in 1826

James Dunlop & and his rubber tire galaxy

I like that composite image, Victor!

Ann