Starship Asterisk*

The Tadpole Galaxy from Hubble

Explanation: Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation of the Dragon (Draco). Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail's star clusters forming smaller satellites of the large spiral galaxy.

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Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA

Click to view full size image

Let's compare the image posted by Victor with the APOD:


A reflexion here: If the Tadpole galaxy got so messed up when it collided with two really quite small satellite galaxies, then what will happen when the Milky Way collides with the Large Magellanic Cloud (and the Small Cloud presumably following afterwards)?

Sci News wrote:

The Large Magellanic Cloud, a dwarf galaxy located approximately 163,000 light-years away, is on a collision course with the Milky Way with which it will merge in about 2.4 billion years, according to new research. This catastrophic event could wake up our Galaxy’s dormant supermassive black hole, which would begin devouring surrounding gas and increase in size by up to 8 times; the Milky Way’s stellar halo will undergo an equally impressive transformation, becoming 5 times more massive; the merger will also gravitationally eject central disk stars into the halo.

Ann

Ann wrote: ↑Mon Jul 15, 2024 5:47 am

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA

Click to view full size image

[...]

A reflexion here: If the Tadpole galaxy got so messed up when it collided with two really quite small satellite galaxies, then what will happen when the Milky Way collides with the Large Magellanic Cloud (and the Small Cloud presumably following afterwards)?

The Milky Way Galaxy and the Large and Small Magellanic Clouds. Image credit: Nina McCurdy / Nick Risinger / NASA.

---

Sci News wrote:

The Large Magellanic Cloud, a dwarf galaxy located approximately 163,000 light-years away, is on a collision course with the Milky Way with which it will merge in about 2.4 billion years, according to new research. This catastrophic event could wake up our Galaxy’s dormant supermassive black hole, which would begin devouring surrounding gas and increase in size by up to 8 times; the Milky Way’s stellar halo will undergo an equally impressive transformation, becoming 5 times more massive; the merger will also gravitationally eject central disk stars into the halo.

Ann

ThanX Ann

Your question is exciting, although I don't know whether anyone will be interested in it in ... generations of humanity.

Regarding the "scientific" paper cited by Victor, I would treat it with caution. According to my analysis and assessment, apart from a series of assumptions, there are no facts or data-based analysis results in it that would support the assumptions. On the contrary, the assumptions are based on a so-called ROTASE model mechanism, which was developed or invented by one of the authors himself and which is based in particular on a large unknown:

"This model assumes that the central black hole of the galaxy emits anti-gravitational or non-gravitational matter in two opposite directions. The emitted matter is called X-matter because the properties of the emitted matter are completely unknown (the "X" stands for "unknown")."

That means that in my opinion the paper written by two PhDs is hypothetical to support a hypothesis (hypothetical model) of another paper.
But okay. This is my personal opinion. The paper was peer-reviewed by 7 people.


Paper: https://www.researchgate.net/publicatio ... ic_Merging
Peer-Review: https://www.sdiarticle5.com/review-history/85417

AVAO wrote: ↑Mon Jul 15, 2024 6:47 am

Ann wrote: ↑Mon Jul 15, 2024 5:47 am

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA

Click to view full size image

[...]

A reflexion here: If the Tadpole galaxy got so messed up when it collided with two really quite small satellite galaxies, then what will happen when the Milky Way collides with the Large Magellanic Cloud (and the Small Cloud presumably following afterwards)?

The Milky Way Galaxy and the Large and Small Magellanic Clouds. Image credit: Nina McCurdy / Nick Risinger / NASA.

---

Sci News wrote:

The Large Magellanic Cloud, a dwarf galaxy located approximately 163,000 light-years away, is on a collision course with the Milky Way with which it will merge in about 2.4 billion years, according to new research. This catastrophic event could wake up our Galaxy’s dormant supermassive black hole, which would begin devouring surrounding gas and increase in size by up to 8 times; the Milky Way’s stellar halo will undergo an equally impressive transformation, becoming 5 times more massive; the merger will also gravitationally eject central disk stars into the halo.

Ann

ThanX Ann

Your question is exciting, although I don't know whether anyone will be interested in it in ... generations of humanity.

Regarding the "scientific" paper cited by Victor, I would treat it with caution. According to my analysis and assessment, apart from a series of assumptions, there are no facts or data-based analysis results in it that would support the assumptions. On the contrary, the assumptions are based on a so-called ROTASE model mechanism, which was developed or invented by one of the authors himself and which is based in particular on a large unknown:

"This model assumes that the central black hole of the galaxy emits anti-gravitational or non-gravitational matter in two opposite directions. The emitted matter is called X-matter because the properties of the emitted matter are completely unknown (the "X" stands for "unknown")."


That means that in my opinion the paper written by two PhDs is hypothetical to support a hypothesis (hypothetical model) of another paper.
But okay. This is my personal opinion. The paper was peer-reviewed by 7 people.


Paper: https://www.researchgate.net/publicatio ... ic_Merging
Peer-Review: https://www.sdiarticle5.com/review-history/85417

Wowzers!!! Thanks for the warning, Jac!

Ann

Ann wrote: ↑Mon Jul 15, 2024 9:36 am Wowzers!!! Thanks for the warning, Jac!

Ann

I like the galaxy
... even if it is not mirrored, like the original images in the hubble legacy archive ...

Original data: NASA/ESA jac berne (flickr)

Small cause, big effect! I’d be curious to see a simulation of how these modest intruders could produce such a dramatic distorsion. If I did not know of the intruders I would have thought that a large galaxy outside the frame was the cause. In Arp 273 a similarly small intruder (if that's indeed what it is) on top right triggers star formation but that’s mostly all it does apparently, while the major arm distorsions seem to come only from the large galaxy below.
p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

Got it, thanks!

AVAO wrote: ↑Mon Jul 15, 2024 6:47 am "This model assumes that the central black hole of the galaxy emits anti-gravitational or non-gravitational matter in two opposite directions. The emitted matter is called X-matter because the properties of the emitted matter are completely unknown (the "X" stands for "unknown")."

my bad. I googled a picture with the intruder(s) marked, and cut it from the paper I didn't bothered to read. I might have seen "X" letters but mistaken them for X-ray mentioning

Christian G. wrote: ↑Mon Jul 15, 2024 1:19 pm

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

Got it, thanks!

Well. I think the author of today's APOD rotated the original NASA images/data so that the small galaxy in the bottom right is clearly visible in the image. That's why the north orientation of the original NASA images is no longer preserved. What he probably didn't know is that these are displayed mirror-inverted in a FITS viewer ...

AVAO wrote: ↑Mon Jul 15, 2024 2:02 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:19 pm

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

Got it, thanks!

Well. I think the author of today's APOD rotated the original NASA images/data so that the small galaxy in the bottom right is clearly visible in the image. That's why the north orientation of the original NASA images is no longer preserved. What he probably didn't know is that these are displayed mirror-inverted in a FITS viewer ...

Right. The rotation is no big deal. The mirroring is slightly unfortunate.

Why doesn't APOD include the relative size/measurements of ANY and EVERY image, as viewed from earth? (Arc, degrees, or apparent at arms length) I can't help to think this is an important aspect of any astronomical image appreciation. Thanks.

Obquote: [cue klaxon] "Intruder Alert! Intruder Alert!" -Star Trek.
Obquote 2: "What you see is what you get!" -Geraldine, played by Flip Wilson.

Are the spikes from stars within the Milky Way?

Psnarf wrote: ↑Mon Jul 15, 2024 5:48 pm Obquote: [cue klaxon] "Intruder Alert! Intruder Alert!" -Star Trek.
Obquote 2: "What you see is what you get!" -Geraldine, played by Flip Wilson.

Are the spikes from stars within the Milky Way?

Every star in the image (and even every galaxy) has diffraction spikes. But only the brightest point sources produce spikes that rise above the background noise to become visible. So almost certainly we're only seeing them on nearby stars. Ones in the Milky Way.

I have to talk about the color of this APOD, because I am, after all, the Color Commentator. And the color of this APOD both delights and bothers me.


When I first saw a picture of the Tadpole Galaxy, it looked like the picture at right. The colors were pale. In the APOD, almost all of the Tadpole Galaxy except the very center is so blue that it could have been made of untold quintillions of Nemophila menziesii, Baby blue eyes!

Okay, I'll confess: Hiroki Kondo's image of an entire field of Baby blue eyes in bloom is one of the most achingly lovely and beautiful pictures that I have ever seen. But do things ever get that blue out in space? My answer is that it is at least okay to show the Pleiades as that amazingly blue:


So, yes, all the bright stars of the Pleiades are blue, and the nebulosity surrounding them is certainly blue. But a whole galaxy?
A galaxy that, at best, is made up of stars of all spectral classes, and which could be made of late-type yellow and red stars almost exclusively?


Let's look at some different types of stellar populations. Let's look at ancient and metal-poor populations, and old and metal-rich, and intermediately aged and metal-rich:


Let's look at a galaxy with a very interesting post-starburst population:



Please click on the picture of NGC 5394 to see the full size of it. Like all at least reasonably big and star-rich galaxies, NGC 5394 has a yellow center made up of predominantly K-type and M-type stars. NGC 5394 also has two elongated arms, which are blue. One of the arms contains very few and small clusters, which suggests that the stars here are typically class A (like Sirius and Vega) rather than spectral class O and B (like the brilliant blue stars in Orion). The other arm contains a few red emission nebulas, which shows that this arm contains some hot bright stars of spectral classes O and B.

But the most interesting thing about NGC 5394 is its brilliantly white stellar "arc" to the upper right of the yellow center. You could argue that this arc is overexposed and that it really contains hot stars of spectral classes O and B, but that does not seem to be the case. NGC 5494 is not very bright in ultraviolet light, which it would be if the stellar arc was made of hot stars. No, this is clearly a still brilliantly bright and densely populated post-starburst area, where the dominant stars are probably spectral classes F and G.

Please note that the stellar arc is smooth. There are no clusters visible here. That in itself suggests that there are no or very few blue stars here, because young blue stars at least of spectral classes O and B are typically found in clusters.

My point? There are few clusters seen in the Tadpole Galaxy. Yes, there are some clusters there, but large parts of the Tadpole Galaxy look smooth. And not only are they smooth, but also bright. High surface brightness, smooth populations of stars are practically never blue. We should not expect such parts of the Tadpole Galaxy to be blue.

And that was my long-winded way of saying that I think that today's APOD is very beautiful in all its blue glory, but I don't find it entirely realistic!

Ann

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA
The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies.png

Intruders? They look to me more like two of the "massive blue clusters" ignited by the now long gone true intruder that created the Tadpole's tail.

What would an image of the Tadpole by the Webb telescope look like?

johnnydeep wrote: ↑Mon Jul 15, 2024 9:18 pm

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA
The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies.png

Intruders? They look to me more like two of the "massive blue clusters" ignited by the now long gone intruder that created the Tadpole's tail.

I agree that "Intruder 2" looks just like a massive cluster that formed as a consequence of "Intruder 1's" intrusion into the Tadpole Galaxy.

I read somewhere that rich open cluster NGC 6231 may have formed as a consequence of globular cluster NGC 6397's passage through the Milky Way's disk. Don't know if this is an accepted theory at all - probably not - but I like the idea.

Ann

Ann wrote: ↑Tue Jul 16, 2024 4:18 am

johnnydeep wrote: ↑Mon Jul 15, 2024 9:18 pm

VictorBorun wrote: ↑Mon Jul 15, 2024 5:05 am Fig. 1. The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies as a local galactic
cluster. The image is credited to: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin
(STScI), G. Hartig (STScI), the ACS Science Team, and ESA
The image of the Tadpole galaxy UGC 10214 with labeled 3 galaxies.png

Intruders? They look to me more like two of the "massive blue clusters" ignited by the now long gone intruder that created the Tadpole's tail.

I agree that "Intruder 2" looks just like a massive cluster that formed as a consequence of "Intruder 1's" intrusion into the Tadpole Galaxy.

I read somewhere that rich open cluster NGC 6231 may have formed as a consequence of globular cluster NGC 6397's passage through the Milky Way's disk. Don't know if this is an accepted theory at all - probably not - but I like the idea.

Globular cluster passed through the Milky Way's disk... (Credit: NASA/ESA and the Hubble Heritage Team (AURA/STScI))

---

...and spawned rich open cluster NGC 6231? (Credit: Casey Good)

---

Ann

The paper that Victor linked to seems to think that both "1" and "2" are intruders. I suppose there are good reasons, but to me, both still look like massive cluster spawned by some now gone true intruder, though granted, "1" is quite large! But I guess I must be wrong.

johnnydeep wrote: ↑Tue Jul 16, 2024 5:43 pm

Ann wrote: ↑Tue Jul 16, 2024 4:18 am

johnnydeep wrote: ↑Mon Jul 15, 2024 9:18 pm

Intruders? They look to me more like two of the "massive blue clusters" ignited by the now long gone intruder that created the Tadpole's tail.

I agree that "Intruder 2" looks just like a massive cluster that formed as a consequence of "Intruder 1's" intrusion into the Tadpole Galaxy.

I read somewhere that rich open cluster NGC 6231 may have formed as a consequence of globular cluster NGC 6397's passage through the Milky Way's disk. Don't know if this is an accepted theory at all - probably not - but I like the idea.

Globular cluster passed through the Milky Way's disk... (Credit: NASA/ESA and the Hubble Heritage Team (AURA/STScI))

---

...and spawned rich open cluster NGC 6231? (Credit: Casey Good)

---

Ann

The paper that Victor linked to seems to think that both "1" and "2" are intruders. I suppose there are good reasons, but to me, both still look like massive cluster spawned by some now gone true intruder, though granted, "1" is quite large! But I guess I must be wrong.

I don't think you "must" be wrong at all! I don't think that there is enough evidence to say what really happened to make the Tadpole Galaxy into what it is.

The way I understand it, judging from the paper than Victor linked to, the authors of that paper aren't quite sure that they are right, either.

Ann

Ann wrote: ↑Tue Jul 16, 2024 6:07 pm

johnnydeep wrote: ↑Tue Jul 16, 2024 5:43 pm

Ann wrote: ↑Tue Jul 16, 2024 4:18 am

I agree that "Intruder 2" looks just like a massive cluster that formed as a consequence of "Intruder 1's" intrusion into the Tadpole Galaxy.

I read somewhere that rich open cluster NGC 6231 may have formed as a consequence of globular cluster NGC 6397's passage through the Milky Way's disk. Don't know if this is an accepted theory at all - probably not - but I like the idea.

Globular cluster passed through the Milky Way's disk... (Credit: NASA/ESA and the Hubble Heritage Team (AURA/STScI))

---

...and spawned rich open cluster NGC 6231? (Credit: Casey Good)

---

Ann

The paper that Victor linked to seems to think that both "1" and "2" are intruders. I suppose there are good reasons, but to me, both still look like massive cluster spawned by some now gone true intruder, though granted, "1" is quite large! But I guess I must be wrong.

I don't think you "must" be wrong at all! I don't think that there is enough evidence to say what really happened to make the Tadpole Galaxy into what it is.

The way I understand it, judging from the paper than Victor linked to, the authors of that paper aren't quite sure that they are right, either.

Ann

Thanks. I only skimmed the paper.

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

What do you mean by east counterclockwise from north? Can you give me an example with a picture?

beryllium732 wrote: ↑Wed Jul 17, 2024 1:14 am

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

What do you mean by east counterclockwise from north? Can you give me an example with a picture?

North is the direction that declination increases in (when north of the celestial equator). East is the direction that RA increases. East is counterclockwise of north, or -90 degrees from north.
_

beryllium732 wrote: ↑Wed Jul 17, 2024 1:14 am

Chris Peterson wrote: ↑Mon Jul 15, 2024 1:16 pm

Christian G. wrote: ↑Mon Jul 15, 2024 1:03 pm p.s. great close-up image AVAO! (but do you mean by "mirrored" that this is not the actual state of the galaxy but an optical effect? I'm not sure I understand)

Astronomical images, by convention, should be presented with east counterclockwise from north. (And ideally with north up, but this convention is often ignored in order to match the geometry of the object to that of the camera, or sometimes for purely aesthetic ends.) This is what we see when we look at the sky, and what telescopes with an even number of reflective surfaces produce. Images presented with with east clockwise from north (as with today's APOD) are considered mirrored (and harder to work with).

What do you mean by east counterclockwise from north? Can you give me an example with a picture?

This is how I learnt it: In astronomical images, north should be up and east to the left.

Ann