APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

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APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by APOD Robot » Sun Oct 16, 2022 4:05 am

Image Barred Spiral Galaxy NGC 1300

Explanation: Across the center of this spiral galaxy is a bar. And at the center of this bar is smaller spiral. And at the center of that spiral is a supermassive black hole.  This all happens in the big, beautiful, barred spiral galaxy cataloged as NGC 1300, a galaxy that lies some 70 million light-years away toward the constellation of the river Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the most detailed Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. How the giant bar formed, how it remains, and how it affects star formation remains an active topic of research.

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by VictorBorun » Sun Oct 16, 2022 6:06 am

I wonder why Wiki says nothing about the angle of observation

To my eye 1 o'clock direction is toward us, because dust lanes are more visible around that direction, backlighted by the bulge.
But is NGC 1300 circular except the bar and the sub-cores at the ends of the bar?
Are galaxy orbital velocities of stars taken to test that circularity?
NGC 1300..jpg
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Nsaarni

Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by Nsaarni » Sun Oct 16, 2022 6:26 am

what is the object on the lower left, about 7:00?
i assume its "just" another galaxy, but it looks reminiscent of the Engraved Hourglass Nebula

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by VictorBorun » Sun Oct 16, 2022 6:55 am

Nsaarni wrote: Sun Oct 16, 2022 6:26 am what is the object on the lower left, about 7:00?
i assume its "just" another galaxy, but it looks reminiscent of the Engraved Hourglass Nebula
NGC1300_HST_6637 Hourglass.jpg
NGC1300_HST_6637 Hourglass+.jpg
...
Click to view full size image 1 or image 2
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Learner

Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by Learner » Sun Oct 16, 2022 8:14 am

"At the centre is a black hole." Black holes allegedly have such strong gravity that nothing, even photons, can escape ... so how is the centre so bright?

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by VictorBorun » Sun Oct 16, 2022 8:41 am

Learner wrote: Sun Oct 16, 2022 8:14 am "At the centre is a black hole." Black holes allegedly have such strong gravity that nothing, even photons, can escape ... so how is the centre so bright?
Black holes are nasty eaters.
Much of the attracted matter never falls into a BH but forms a disk a light hour wide and a pair of jets a hundred thousand ly long.
But not in NGC 1300. Its central BH is quiet. You only can guess a quiet central BH is there if you detect high orbital velocities of stars and interstellar gas in an area of 30 or 300 ly around it.
Or you can image it with JWST. Even optically dark, a thin accretion disk behind a thick dust cloud may be bright in Mid Infra Red. It may show high velocities in MIR spectra too

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by orin stepanek » Sun Oct 16, 2022 12:45 pm

NGC1300_HST_1080.jpg
NGC1300; A beautiful galaxy! Nice! :D
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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by De58te » Sun Oct 16, 2022 1:25 pm

Something confusing again. The Wikipedia link for NGC 1300 says this, "The galaxy is about 110,000 light-years across (about the half size of the Milky Way at 200,000)." Yet several websites such as space. com say that the Milky Way's diameter is about 100,000 ly across. So what is the truth? Is the Milky Way 100,000 or 200,000 ly?

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by Chris Peterson » Sun Oct 16, 2022 1:35 pm

De58te wrote: Sun Oct 16, 2022 1:25 pm Something confusing again. The Wikipedia link for NGC 1300 says this, "The galaxy is about 110,000 light-years across (about the half size of the Milky Way at 200,000)." Yet several websites such as space. com say that the Milky Way's diameter is about 100,000 ly across. So what is the truth? Is the Milky Way 100,000 or 200,000 ly?
When talking distances or sizes in astronomy, we're usually happy if our uncertainty is only a factor of two!

Seriously, though, nobody really knows the size of our own galaxy, which ironically is the most difficult one to study in many respects, given our position inside it.
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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by XgeoX » Sun Oct 16, 2022 2:57 pm

I wonder if the Earth’s bar would be large enough to form a grand spiral inside. Probably not big enough to do so but it’s vexing we can’t get a full on view of the Milky Way!

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by Ann » Sun Oct 16, 2022 4:43 pm

NGC 1300 is interesting for several reasons. Obviously for the enormous length of its bar. But it is interesting for other reasons, too.

For one thing, the entire galaxy is really faint, apart from its nuclear region:

NGC 1300 James D Wray.png
Faint-looking NGC 1300 from "The Color Atlas of Galaxies" by James D Wray.

The picture of the faint-looking NGC 1300 is from my own copy of "The Color Atlas of Galaxies" (1988) by James D Wray. The pictures in Wray's atlas have been printed on glossy black paper, so when I took a picture of Wray's image using my cellphone, the glossiness of the page caused reflections that look a bit like broad jets or streamers. These features are not real and not a part of Wray's photograph.

Searching the web, I found another picture that showed NGC 1300 in much the same way as James D Wray, with a very bright center but otherwise faint features overall:


We do see more of the arms of NGC 1300 in the photo by Orange County Astronomers than we see in Wray's image. Actually, most spiral galaxies in Wray's atlas have much fainter arms than we are used to seeing, because Wray never amped up the brightness of spiral arms. (He didn't have the resolution to do so, obviously.) But not all galaxies in his atlas are limb-challenged as NGC 1300.

Let's look at Wray's version of NGC 986, which is another galaxy with a long bar:

NGC 986 James D Wray.png
NGC 986. Photo: James D Wray.

Wray's picture of NGC 986 is not quite comparable to his picture of NGC 1300, because he used a somewhat larger telescope for his picture of NGC 986 (a 1 meter telescope, versus a 0.7 meter telescope for NGC 1300), and also he used a longer exposure time for NGC 986.

Nevertheless, it is clear that these two galaxies are indeed different. NGC 986 is so rich in dust that it is two magnitudes brighter in far infrared light than in B light, whereas NGC 1300 is somewhat fainter in infrared light than in B light. Galaxies that are bright in far infrared light contain a lot of dust and are often rich in star formation. It is hard to judge from "prettified" images on the web, but I would be surprised if NGC 986 does not contain a lot more star formation than NGC 1300.


Another interesting thing about NGC 1300, compared with NGC 986, is that its arms appear to be "pressed down" and almost "doubled over" above its nuclear region, as if something was pushing them down there. One arm appears to be particularly "weighed down". But if the arms are hard pressed to rise much above the central bar, the core of NGC 1300 appears round and face on.


I have read somewhere that if a galaxy has a very massive black hole, then the pull of the black hole will affect the "pitch angle" of the arms so that they are not as "open", but "lower down" in relation to the core. According to Wikipedia, the central black hole of NGC 1300 may have a mass of ~7.3×107 M (with a large uncertainty). If we assume that the mass of the central black hole of NGC 1300 is indeed ~73 million solar masses, then it is more than 15 times more massive than the black hole of the Milky Way, whose mass is ~ 4 million solar masses. Perhaps the black hole of NGC 1300 is indeed pulling down its arms?

Ann
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DL MARTIN

Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by DL MARTIN » Sun Oct 16, 2022 5:10 pm

If a nebula burst forth on a far side of this galaxy, would it not take 100,000 years for it to be perceived on the opposite?

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by AVAO » Sun Oct 16, 2022 6:25 pm

Ann wrote: Sun Oct 16, 2022 4:43 pm NGC 1300 is interesting for several reasons. Obviously for the enormous length of its bar. But it is interesting for other reasons, too.
For one thing, the entire galaxy is really faint, apart from its nuclear region:
...
Searching the web, I found another picture that showed NGC 1300 in much the same way as James D Wray, with a very bright center but otherwise faint features overall:
Ann
It's all a matter of wavelength ...;-)

The first image shows the MUSE data. The golden glows mainly correspond to clouds of ionised hydrogen, oxygen and sulphur gas, marking the presence of newly born stars, while the bluish regions in the background reveal the distribution of young stars.
Image
The second image shows the MUSE image is overlaid with the radio data from ALMA (showing up in brownish-orange), revealing the cold clouds of molecular gas, stellar nurseries where new stars come to life.
Image
Credit:ESO/ALMA (ESO/NAOJ/NRAO)/PHANGS
https://www.eso.org/public/images/comparisons/eso2110b/

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by Ann » Sun Oct 16, 2022 7:06 pm

AVAO wrote: Sun Oct 16, 2022 6:25 pm
Ann wrote: Sun Oct 16, 2022 4:43 pm NGC 1300 is interesting for several reasons. Obviously for the enormous length of its bar. But it is interesting for other reasons, too.
For one thing, the entire galaxy is really faint, apart from its nuclear region:
...
Searching the web, I found another picture that showed NGC 1300 in much the same way as James D Wray, with a very bright center but otherwise faint features overall:
Ann
It's all a matter of wavelength ...;-)

The first image shows the MUSE data. The golden glows mainly correspond to clouds of ionised hydrogen, oxygen and sulphur gas, marking the presence of newly born stars, while the bluish regions in the background reveal the distribution of young stars.
Image
The second image shows the MUSE image is overlaid with the radio data from ALMA (showing up in brownish-orange), revealing the cold clouds of molecular gas, stellar nurseries where new stars come to life.
Image
Credit:ESO/ALMA (ESO/NAOJ/NRAO)/PHANGS
https://www.eso.org/public/images/comparisons/eso2110b/

Okay, good point. NGC 1300 certainly doesn't lack star formation! :D


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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by johnnydeep » Sun Oct 16, 2022 8:33 pm

DL MARTIN wrote: Sun Oct 16, 2022 5:10 pm If a nebula burst forth on a far side of this galaxy, would it not take 100,000 years for it to be perceived on the opposite?
You know the answer to that question, and the answer is "yes"!
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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by johnnydeep » Sun Oct 16, 2022 8:53 pm

Ann wrote: Sun Oct 16, 2022 4:43 pm ...
I have read somewhere that if a galaxy has a very massive black hole, then the pull of the black hole will affect the "pitch angle" of the arms so that they are not as "open", but "lower down" in relation to the core. According to Wikipedia, the central black hole of NGC 1300 may have a mass of ~7.3×107 M (with a large uncertainty). If we assume that the mass of the central black hole of NGC 1300 is indeed ~73 million solar masses, then it is more than 15 times more massive than the black hole of the Milky Way, whose mass is ~ 4 million solar masses. Perhaps the black hole of NGC 1300 is indeed pulling down its arms?

Ann
I don't know about that. I can't find a reference for the mass of NGC 1300 itself, but let's assume it is only half the low end of the MW's mass estimate (200e9 - 600e9 solar masses), and also disregard the mass of any dark matter (which could add another factor of 2 or more!), we find that at a mass of 7e7, the central BH of NGC 1300 would only be about 7e7/100e9 = 0.0007 = 0.07%, or less that one thousandth the total mass of NGC 1300. Nearby mass agglomerations would have a much greater gravitational effect on the spiral arms that the central BH. [ Note: I recall past discussions of the "pitch angle and central BH effect" stuff too, but I still can't understand it based on gravitational effects. ]
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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by VictorBorun » Sun Oct 16, 2022 10:09 pm

johnnydeep wrote: Sun Oct 16, 2022 8:53 pm
Ann wrote: Sun Oct 16, 2022 4:43 pm ...
I have read somewhere that if a galaxy has a very massive black hole, then the pull of the black hole will affect the "pitch angle" of the arms so that they are not as "open", but "lower down" in relation to the core. According to Wikipedia, the central black hole of NGC 1300 may have a mass of ~7.3×107 M (with a large uncertainty). If we assume that the mass of the central black hole of NGC 1300 is indeed ~73 million solar masses, then it is more than 15 times more massive than the black hole of the Milky Way, whose mass is ~ 4 million solar masses. Perhaps the black hole of NGC 1300 is indeed pulling down its arms?

Ann
I don't know about that. I can't find a reference for the mass of NGC 1300 itself, but let's assume it is only half the low end of the MW's mass estimate (200e9 - 600e9 solar masses), and also disregard the mass of any dark matter (which could add another factor of 2 or more!), we find that at a mass of 7e7, the central BH of NGC 1300 would only be about 7e7/100e9 = 0.0007 = 0.07%, or less that one thousandth the total mass of NGC 1300. Nearby mass agglomerations would have a much greater gravitational effect on the spiral arms that the central BH. [ Note: I recall past discussions of the "pitch angle and central BH effect" stuff too, but I still can't understand it based on gravitational effects. ]
well, I guess they mean the influence of the central BH on evolution of different fractions of the stellar population.
In low gravity the stars can cross the core in random directions, but near the central BH the gravity does matter and makes the interactions between two closely passing stars to direct the more massive star of the two mostly down to the BH and the less massive star mostly up from the BH.
Even a 100 ly small spheric region of gravity and separation can influence all the core, in time, giving a lot of stars many chances to go through that separator region. Eventually the stellar population of the core loses its 10 Suns mass giants and gets redder with its red dwarf fraction.
Or there can be a dozen of such separation regions, all close to the centre of the core and working together.

One more thing they mean can be that a few catastrophic merges of BHs and stars can blow away the interstellar gas and dust out of the core. That would stop the formation of new 10 Suns mass giants

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Re: APOD: Barred Spiral Galaxy NGC 1300 (2022 Oct 16)

Post by johnnydeep » Mon Oct 17, 2022 4:14 pm

VictorBorun wrote: Sun Oct 16, 2022 10:09 pm
johnnydeep wrote: Sun Oct 16, 2022 8:53 pm
Ann wrote: Sun Oct 16, 2022 4:43 pm ...
I have read somewhere that if a galaxy has a very massive black hole, then the pull of the black hole will affect the "pitch angle" of the arms so that they are not as "open", but "lower down" in relation to the core. According to Wikipedia, the central black hole of NGC 1300 may have a mass of ~7.3×107 M (with a large uncertainty). If we assume that the mass of the central black hole of NGC 1300 is indeed ~73 million solar masses, then it is more than 15 times more massive than the black hole of the Milky Way, whose mass is ~ 4 million solar masses. Perhaps the black hole of NGC 1300 is indeed pulling down its arms?

Ann
I don't know about that. I can't find a reference for the mass of NGC 1300 itself, but let's assume it is only half the low end of the MW's mass estimate (200e9 - 600e9 solar masses), and also disregard the mass of any dark matter (which could add another factor of 2 or more!), we find that at a mass of 7e7, the central BH of NGC 1300 would only be about 7e7/100e9 = 0.0007 = 0.07%, or less that one thousandth the total mass of NGC 1300. Nearby mass agglomerations would have a much greater gravitational effect on the spiral arms that the central BH. [ Note: I recall past discussions of the "pitch angle and central BH effect" stuff too, but I still can't understand it based on gravitational effects. ]
well, I guess they mean the influence of the central BH on evolution of different fractions of the stellar population.
In low gravity the stars can cross the core in random directions, but near the central BH the gravity does matter and makes the interactions between two closely passing stars to direct the more massive star of the two mostly down to the BH and the less massive star mostly up from the BH.
Even a 100 ly small spheric region of gravity and separation can influence all the core, in time, giving a lot of stars many chances to go through that separator region. Eventually the stellar population of the core loses its 10 Suns mass giants and gets redder with its red dwarf fraction.
Or there can be a dozen of such separation regions, all close to the centre of the core and working together.

One more thing they mean can be that a few catastrophic merges of BHs and stars can blow away the interstellar gas and dust out of the core. That would stop the formation of new 10 Suns mass giants
There must be simulations out there I suppose...
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