APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

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APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by APOD Robot » Fri Feb 12, 2021 5:11 am

Image Spiral Galaxy NGC 1350

Explanation: This gorgeous island universe lies about 85 million light-years distant in the southern constellation Fornax. Inhabited by young blue star clusters, the tightly wound spiral arms of NGC 1350 seem to join in a circle around the galaxy's large, bright nucleus, giving it the appearance of a cosmic eye. In fact, NGC 1350 is about 130,000 light-years across. That makes it as large or slightly larger than the Milky Way. For earth-based astronomers, NGC 1350 is seen on the outskirts of the Fornax cluster of galaxies, but its estimated distance suggests that it is not itself a cluster member. Of course, the bright spiky stars in the foreground of this telescopic field of view are members of our own spiral Milky Way galaxy.

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Ann » Fri Feb 12, 2021 6:31 am

Can't resist comparing the Eye Galaxy with the Black Eye Galaxy, M64. Both galaxies have prominent inner dust lanes near their nucleus, although the dust lane of M64 is much darker and more startling than the inner dust lane of NGC 1350. NGC 1350, by contrast, has a very prominent ring outside its central bulge, and not much of a disk outside this ring.

NGC 1350 and M64 are classified as non-barred spirals with tightly wound arms. They have very similar colors, with a B-V index of 0.87 for NGC 1350 and 0.84 for M64. This means that both galaxies are relatively red and relatively low in star formation.

Remarkably, I could find only one other reasonably good picture of NGC 1350 on the net, and I didn't much like that picture because I found its colors weird.

The bluish cast of the ESO image may be due to the fact that the exposure through a blue filter was twice as long as the exposures through the other filters. At the same time, the fact that a disk is visible outside the prominent ring of NGC 1350 in ESO's picture, which is not really the case in the Selby/Keller image, may be due to the fact that ESO used an infrared filter to bring out the presence of small cool stars in the disk.

Finally, it's really quite weird that this elegant galaxy is so unknown, and has been photographed so rarely. It must be the galaxy's southern position, and the "northern bias" of astronomy (due to the fact that most of the Earth's astronomers live north of the equator), that is to blame for the snubbing of NGC 1350.

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by orin stepanek » Fri Feb 12, 2021 1:16 pm

NGC1350_crop1024.jpg

Eye Galaxy! Good name for NGC1350! Spiked star makes good accent
for this photo! 8-) Has a ring within a ring; outside ring kinda slight!
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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Wadsworth » Fri Feb 12, 2021 3:08 pm

When I zoom in on the Galaxy in this image my mind sets it to motion and It starts to spin slowly.
I guess our mind knows how things are supposed to spin..

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Chris Peterson » Fri Feb 12, 2021 3:16 pm

Wadsworth wrote:
Fri Feb 12, 2021 3:08 pm
When I zoom in on the Galaxy in this image my mind sets it to motion and It starts to spin slowly.
I guess our mind knows how things are supposed to spin..
Although most spiral galaxies have arms that lag, a few have arms that lead. And quite a few we don't really know for sure, because it can be difficult to measure. This probably spins the way your mind expects... but it may not.
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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by neufer » Fri Feb 12, 2021 4:43 pm

Chris Peterson wrote:
Fri Feb 12, 2021 3:16 pm
Wadsworth wrote:
Fri Feb 12, 2021 3:08 pm

When I zoom in on the Galaxy in this image my mind sets it to motion and It starts to spin slowly.
I guess our mind knows how things are supposed to spin.
Although most spiral galaxies have arms that lag, a few have arms that lead. And quite a few we don't really know for sure, because it can be difficult to measure. This probably spins the way your mind expects... but it may not.
  • (Almost?) all barred spiral galaxies have arms that lag.
https://en.wikipedia.org/wiki/Black_Eye_Galaxy wrote: <<The Black Eye Galaxy (Messier 64, M64, or NGC 4826) is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices. A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the "Black Eye" or "Evil Eye" galaxy. M64 is well known among amateur astronomers due to its form in small telescopes and visibility across inhabited latitudes.

The morphological classification in the De Vaucouleurs system is (R)SA(rs)ab, where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'ab' says the spiral arms are fairly tightly wound. Ann et al. (2015) gave it a class of SABa, suggesting a weakly barred spiral galaxy with tightly wound arms.

The interstellar medium of Messier 64 consists of two counter-rotating disks that are approximately equal in mass. The inner disk contains the prominent dust lanes of the galaxy. The stellar population of the galaxy exhibits no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde orbit, or the continued accretion of gas clouds from the intergalactic medium.>>
https://en.wikipedia.org/wiki/NGC_4622 wrote: <<NGC 4622 is a face-on unbarred spiral galaxy with a very prominent ring structure located in the constellation Centaurus. The galaxy is a member of the Centaurus Cluster. The spiral galaxy, NGC 4622 (also called Backward galaxy), lies approx. 111 million light years away from Earth in the constellation Centaurus. NGC 4622 is an example of a galaxy with leading spiral arms. In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation. In NGC 4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation. This may be the result of a gravitational interaction between NGC 4622 and another galaxy or the result of a merger between NGC 4622 and a smaller object.

NGC 4622 also has a single inner trailing spiral arm. Although it was originally suspected that the inner spiral arm was a leading arm, the observations that established that the outer arms were leading also established that the inner arm was trailing.

These results were met with skepticism in part because they contradicted conventional wisdom with one quote being “so you’re the backward astronomers who found the backward galaxy.” The fact that a pair of arms could lead was not easy to accept. Astronomical objections centered on the fact that dust reddening and cloud silhouettes were used to determine that the outer arms lead. The galaxy disk is tilted only 19 degrees from face-on making near to far-side effects of dust hard to discern and because clumpy dust clouds might be concentrated on one side of the disk, creating misleading results.

While the presence of backward arms in a galaxy may seem like an inconvenient truth to many, two independent methods now indicate that NGC 4622's arms do indeed behave in a very unusual fashion, with the outer arms winding outward in the same direction the disk turns.>>
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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Alanh » Fri Feb 12, 2021 8:59 pm

Hi. When I look at it I have to wonder because it must be spinning somewhat and the gravity it has do these things attract material from space flying by and get bigger? When I look close at the picture I get the impression that it is spinning. Or is it so big that any spinning motion is lost because of its size. What is it that makes planets spin and galaxies spin so I would assume the whole universe is spinning in a huge circle too.

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Chris Peterson » Sat Feb 13, 2021 3:16 am

Alanh wrote:
Fri Feb 12, 2021 8:59 pm
Hi. When I look at it I have to wonder because it must be spinning somewhat and the gravity it has do these things attract material from space flying by and get bigger? When I look close at the picture I get the impression that it is spinning. Or is it so big that any spinning motion is lost because of its size. What is it that makes planets spin and galaxies spin so I would assume the whole universe is spinning in a huge circle too.
Massive objects don't tend to get more massive by accumulating stuff. The vast majority of material that might be around a galaxy will be in an open (hyperbolic) orbit. It will approach and then leave the galaxy, never to return. Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.
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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by VictorBorun » Sat Feb 13, 2021 10:53 am

Chris Peterson wrote:
Sat Feb 13, 2021 3:16 am
Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.
Can you please give more details?
How can a galaxy or a star form in the first place? How can they manage to drop the energy and the rotation momemtum?
OK, the energy can be radiated to the outer space by photons and neutrinos.
But those particles are ultra-relativistic; they carry more energy than momentum.
To lose its rotation momentum, the proto-galaxy or a proto-star cloud has to kick away some of its hadron matter, does not it?

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by VictorBorun » Sat Feb 13, 2021 11:40 am

Ann wrote:
Fri Feb 12, 2021 6:31 am
Remarkably, I could find only one other reasonably good picture of NGC 1350 on the net, and I didn't much like that picture because I found its colors weird.

The bluish cast of the ESO image may be due to the fact that the exposure through a blue filter was twice as long as the exposures through the other filters. At the same time, the fact that a disk is visible outside the prominent ring of NGC 1350 in ESO's picture, which is not really the case in the Selby/Keller image, may be due to the fact that ESO used an infrared filter to bring out the presence of small cool stars in the disk.

Finally, it's really quite weird that this elegant galaxy is so unknown, and has been photographed so rarely. It must be the galaxy's southern position, and the "northern bias" of astronomy (due to the fact that most of the Earth's astronomers live north of the equator), that is to blame for the snubbing of NGC 1350.

Ann
I think I see two planes each with a ring of its own. The inner ring looks like this.
Its ESO's pic of the NGC 1350 that I compressed horizontally.
Looking closely at the dust visibility near the central bulge we can see that ESO oriented this pic so that the observer is at 12 o'clock.
To see the outer ring I rotated the pic by 45° counter-clockwise and compressed horizontally.

Can there by elliptical rings? A Kepplerian orbit can be an ellipsis, but the gravitational core has to be off-center, at one of the two focii.
A pendulum orbit can be an ellipsis, but the gravitation source has to be distributed in a globe cloud with constant density.
A tidally deformed ring can be elliptical, but there must be another gravitation source for the tidal forces.

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by Chris Peterson » Sat Feb 13, 2021 2:06 pm

VictorBorun wrote:
Sat Feb 13, 2021 10:53 am
Chris Peterson wrote:
Sat Feb 13, 2021 3:16 am
Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.
Can you please give more details?
How can a galaxy or a star form in the first place? How can they manage to drop the energy and the rotation momemtum?
OK, the energy can be radiated to the outer space by photons and neutrinos.
But those particles are ultra-relativistic; they carry more energy than momentum.
To lose its rotation momentum, the proto-galaxy or a proto-star cloud has to kick away some of its hadron matter, does not it?
We don't know how galaxies form. But most likely they start with concentrations of gas and dark matter. Such concentrations can form because the material is dense enough to behave as a fluid, meaning that particles interact often enough that there is extensive transfer of angular momentum. This is the same thing that happens in accretion discs, from which individual stars and planetary systems form.
Chris

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Re: APOD: Spiral Galaxy NGC 1350 (2021 Feb 12)

Post by VictorBorun » Sat Feb 13, 2021 5:24 pm

Chris Peterson wrote:
Sat Feb 13, 2021 2:06 pm
VictorBorun wrote:
Sat Feb 13, 2021 10:53 am
Chris Peterson wrote:
Sat Feb 13, 2021 3:16 am
Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.
Can you please give more details?
How can a galaxy or a star form in the first place? How can they manage to drop the energy and the rotation momemtum?
OK, the energy can be radiated to the outer space by photons and neutrinos.
But those particles are ultra-relativistic; they carry more energy than momentum.
To lose its rotation momentum, the proto-galaxy or a proto-star cloud has to kick away some of its hadron matter, does not it?
We don't know how galaxies form. But most likely they start with concentrations of gas and dark matter. Such concentrations can form because the material is dense enough to behave as a fluid, meaning that particles interact often enough that there is extensive transfer of angular momentum. This is the same thing that happens in accretion discs, from which individual stars and planetary systems form.
OK, some of the momentum is transferred between different parts of the cloud and annihilated. But the total rotation momentum of a disk would stay.
Is it what's different about a star and a galaxy?
A proto-galaxy cloud collapses to a disk galaxy and remains a disk ever after. It's hard to kick away some matter for good because of the dark matter halo gravitation; so the disk keeps on rotating and can not collapse any further.
A proto-star cloud collapses to a proto-star disk and goes on to shed some rotation momentum and collapse down to a star.

They say, Look at the pair of jets from this proto-star! But the most matter kicked away must be in the plane of the proto-star disk; it's just more diffused and less dusty, hence hard to see.