APOD: Virgo Cluster Galaxies (2020 Oct 10)

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APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by APOD Robot » Sat Oct 10, 2020 4:05 am

Image Virgo Cluster Galaxies

Explanation: Galaxies of the Virgo Cluster are scattered across this deep telescopic field of view. The cosmic scene spans about three Full Moons, captured in dark skies near Jalisco, Mexico, planet Earth. About 50 million light-years distant, the Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Prominent here are Virgo's bright elliptical galaxies from the Messier catalog, M87 at the top left, and M84 and M86 seen (bottom to top) below and right of center. M84 and M86 are recognized as part of Markarian's Chain, a visually striking line-up of galaxies vertically on the right side of this frame. Near the middle of the chain lies an intriguing interacting pair of galaxies, NGC 4438 and NGC 4435, known to some as Markarian's Eyes. Of course giant elliptical galaxy M87 dominates the Virgo cluster. It's the home of a super massive black hole, the first black hole ever imaged by planet Earth's Event Horizon Telescope.

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by shaileshs » Sat Oct 10, 2020 5:10 am

I'm wondering about this statement - "Of course giant elliptical galaxy M87 dominates the Virgo cluster". To me, M86 seems larger than M87. No ? Both seem to be of similar brightness and at almost same distance.. I didn't search a lot to see size, I'm just going to by my eyes. Although M87 might be more interesting (with supergiant blackhole w/ jets coming out in both directions etc,), just for size comparison, to me, M86 seems larger than M87.

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sat Oct 10, 2020 6:23 am

shaileshs wrote:
Sat Oct 10, 2020 5:10 am
I'm wondering about this statement - "Of course giant elliptical galaxy M87 dominates the Virgo cluster". To me, M86 seems larger than M87. No ? Both seem to be of similar brightness and at almost same distance.. I didn't search a lot to see size, I'm just going to by my eyes. Although M87 might be more interesting (with supergiant blackhole w/ jets coming out in both directions etc,), just for size comparison, to me, M86 seems larger than M87.
M86 can look (and be) visually larger than M87 if M87 is more compressed. But M87 may still be considerably more massive than M86, even if its optical size is slightly smaller.

According to Wikipedia, M87 has 12,000 globular clusters, compared with 3,800 for M86.
Wikipedia wrote about M87:

M87 is one of the most massive galaxies in the local Universe. Its diameter is estimated at 240,000 light-years, which is slightly larger than that of the Milky Way. As an elliptical galaxy, the galaxy is a spheroid rather than a flattened disc, accounting for the substantially larger mass of M87. Within a radius of 32 kiloparsecs (100,000 light-years), the mass is (2.4±0.6)×1012 times the mass of the Sun, which is double the mass of the Milky Way galaxy. As with other galaxies, only a fraction of this mass is in the form of stars: M87 has an estimated mass to luminosity ratio of 6.3 ± 0.8; that is, only about one part in six of the galaxy's mass is in the form of stars that radiate energy. This ratio varies from 5 to 30, approximately in proportion to r1.7 in the region of 9–40 kiloparsecs (29,000–130,000 light-years) from the core. The total mass of M87 may be 200 times that of the Milky Way.
Also according to Wikipedia, M87 may contain a trillion stars, whereas the number of stars in M86 is "only" >400 billion.

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sat Oct 10, 2020 11:04 am

I don't know why I can't do Youtube anymore. :(

Anyway, this little snippet of a video was posted by Dr. Becky. This is what she wrote:
Dr Becky wrote:

To wrap up our celebrations of #WorldSpaceWeek here’s a 3D recreation of the real positions and images of galaxies in the Universe as seen by the Sloan Digital Sky Survey (SDSS). Each point you see is a galaxy of over a billion stars somewhere in our Universe. SDSS observed over 1 million galaxies and yet this is still only a tiny fraction of the total number of galaxies in the universe. Many galaxies are part of huge clusters, or groups, with huge empty voids between them. The movie starts by flying right through a large nearby cluster of galaxies and later circles the back around about 2 billion light-years from Earth (to see the full movie, head to my Twitter @drbecky_ or Instagram @drbecky_s). By analysing the positions and movements of galaxies in the Universe, we can work out what forces govern their movement and we find once again more evidence in favour of unseen dark matter and dark energy.
To those of you who've got Facebook or Instagram, go find Dr Becky's Facebook or Instagram to find the full movie. I really, really like the little snippet that we saw here! Is the nearby galaxy cluster that Dr. Becky talks about the Virgo Cluster? Who knows?

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by orin stepanek » Sat Oct 10, 2020 11:09 am

markarian_FernandoPena1024.jpg

A beautiful APOD; as per usual!🤩 APOD dose such a nice job with their selections! Even has a little blue there for you Ann! have to look at the bigger picture to see! :roll:
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by neufer » Sat Oct 10, 2020 12:09 pm

APOD Robot wrote:
Sat Oct 10, 2020 4:05 am
Image Virgo Cluster Galaxies

Explanation: M84 and M86 are recognized as part of Markarian's Chain, a visually striking line-up of galaxies vertically on the right side of this frame. Near the middle of the chain lies an intriguing interacting pair of galaxies, NGC 4438 and NGC 4435, known to some as Markarian's Eyes. Of course giant elliptical galaxy M87 dominates the Virgo cluster. It's the home of a super massive black hole, the first black hole ever imaged by planet Earth's Event Horizon Telescope.
https://en.wikipedia.org/wiki/Eyes_Galaxies wrote:
<<In the 2014 film Interstellar, "NGC 4438" along with specific observation data can be seen in Murphy Cooper (Jessica Chastain)'s notepad during the film's climactic sequence. As the presence of a supermassive black hole in the AGC of NGC 4438 is one of two leading theories, the galaxy is potentially that accessed by the wormhole in the film.>>
Near the middle of Markarian's Chain lies an intriguing interacting pair of galaxies, NGC 4435 & NGC 4438: Markarian's Eyes.
Art Neuendorffer

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by johnnydeep » Sat Oct 10, 2020 5:48 pm

APOD Robot wrote:
Sat Oct 10, 2020 4:05 am
Image Virgo Cluster Galaxies

Explanation: Galaxies of the Virgo Cluster are scattered across this deep telescopic field of view. The cosmic scene spans about three Full Moons, captured in dark skies near Jalisco, Mexico, planet Earth. About 50 million light-years distant, the Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Prominent here are Virgo's bright elliptical galaxies from the Messier catalog, M87 at the top left, and M84 and M86 seen (bottom to top) below and right of center. M84 and M86 are recognized as part of Markarian's Chain, a visually striking line-up of galaxies vertically on the right side of this frame. Near the middle of the chain lies an intriguing interacting pair of galaxies, NGC 4438 and NGC 4435, known to some as Markarian's Eyes. Of course giant elliptical galaxy M87 dominates the Virgo cluster. It's the home of a super massive black hole, the first black hole ever imaged by planet Earth's Event Horizon Telescope.
The Virgo Cluster is "one of my favorite things"! How appropriate that APOD picked it on my birthday! This photo is so nice it could pass for a Hubble pic - hard to believe it was taken from the surface of earth.
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by johnnydeep » Sat Oct 10, 2020 5:56 pm

Ann wrote:
Sat Oct 10, 2020 11:04 am
I don't know why I can't do Youtube anymore. :(

Anyway, this little snippet of a video was posted by Dr. Becky. This is what she wrote:
Dr Becky wrote:

To wrap up our celebrations of #WorldSpaceWeek here’s a 3D recreation of the real positions and images of galaxies in the Universe as seen by the Sloan Digital Sky Survey (SDSS). Each point you see is a galaxy of over a billion stars somewhere in our Universe. SDSS observed over 1 million galaxies and yet this is still only a tiny fraction of the total number of galaxies in the universe. Many galaxies are part of huge clusters, or groups, with huge empty voids between them. The movie starts by flying right through a large nearby cluster of galaxies and later circles the back around about 2 billion light-years from Earth (to see the full movie, head to my Twitter @drbecky_ or Instagram @drbecky_s). By analysing the positions and movements of galaxies in the Universe, we can work out what forces govern their movement and we find once again more evidence in favour of unseen dark matter and dark energy.
To those of you who've got Facebook or Instagram, go find Dr Becky's Facebook or Instagram to find the full movie. I really, really like the little snippet that we saw here! Is the nearby galaxy cluster that Dr. Becky talks about the Virgo Cluster? Who knows?

Ann
Dr. Becky is great! I believe that YouTube link you posted is actually an animated gif, not a video. And I've found that even YouTube videos have to have a specific format to be recognized as such by this forum. For example, this works - "https://www.youtube.com/watch?v=ppIk7h0XHBE":
Click to play embedded YouTube video.
But this doesn't - "https://youtu.be/ppIk7h0XHBE"

[youtube]https://youtu.be/ppIk7h0XHBE[/youtube]
"To Boldly Go......Beyond The Fields We Know."

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sat Oct 10, 2020 6:48 pm

johnnydeep wrote:
Sat Oct 10, 2020 5:56 pm
Ann wrote:
Sat Oct 10, 2020 11:04 am
I don't know why I can't do Youtube anymore. :(

Anyway, this little snippet of a video was posted by Dr. Becky. This is what she wrote:
Dr Becky wrote:

To wrap up our celebrations of #WorldSpaceWeek here’s a 3D recreation of the real positions and images of galaxies in the Universe as seen by the Sloan Digital Sky Survey (SDSS). Each point you see is a galaxy of over a billion stars somewhere in our Universe. SDSS observed over 1 million galaxies and yet this is still only a tiny fraction of the total number of galaxies in the universe. Many galaxies are part of huge clusters, or groups, with huge empty voids between them. The movie starts by flying right through a large nearby cluster of galaxies and later circles the back around about 2 billion light-years from Earth (to see the full movie, head to my Twitter @drbecky_ or Instagram @drbecky_s). By analysing the positions and movements of galaxies in the Universe, we can work out what forces govern their movement and we find once again more evidence in favour of unseen dark matter and dark energy.
To those of you who've got Facebook or Instagram, go find Dr Becky's Facebook or Instagram to find the full movie. I really, really like the little snippet that we saw here! Is the nearby galaxy cluster that Dr. Becky talks about the Virgo Cluster? Who knows?

Ann
Dr. Becky is great! I believe that YouTube link you posted is actually an animated gif, not a video. And I've found that even YouTube videos have to have a specific format to be recognized as such by this forum. For example, this works - "https://www.youtube.com/watch?v=ppIk7h0XHBE":
Click to play embedded YouTube video.
But this doesn't - "https://youtu.be/ppIk7h0XHBE"

[youtube]https://youtu.be/ppIk7h0XHBE[/youtube]
Thanks for the tips on posting Youtube videos, Johnny, and thanks for that great video with Dr Becky!

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by NCTom » Sat Oct 10, 2020 11:03 pm

I can see why the Virgo is such a favorite shot. There are two especially pretty barred spirals to the left of lower center adding to an already beautiful composition. Happy Birthday, Johnny.

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by johnnydeep » Sun Oct 11, 2020 12:17 am

NCTom wrote:
Sat Oct 10, 2020 11:03 pm
I can see why the Virgo is such a favorite shot. There are two especially pretty barred spirals to the left of lower center adding to an already beautiful composition. Happy Birthday, Johnny.
I think you must mean these two? (from a higher res pic I found elsewhere*, here zoomed in and rotated) (Oh, and thanks!)
[(*) the original larger image is http://www.sun.org/uploads/images/Virgocluster.jpg]
99832F3A-25B8-4C1A-B690-54D8AAA20789.jpeg
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sun Oct 11, 2020 6:09 am

johnnydeep wrote:
Sun Oct 11, 2020 12:17 am
NCTom wrote:
Sat Oct 10, 2020 11:03 pm
I can see why the Virgo is such a favorite shot. There are two especially pretty barred spirals to the left of lower center adding to an already beautiful composition. Happy Birthday, Johnny.
I think you must mean these two? (from a higher res pic I found elsewhere*, here zoomed in and rotated) (Oh, and thanks!)
[(*) the original larger image is http://www.sun.org/uploads/images/Virgocluster.jpg]

99832F3A-25B8-4C1A-B690-54D8AAA20789.jpeg
Johnny, is it your birthday? Or was yesterday your birthday? In any case, congratulations!


















As for those barred galaxies in the Virgo cluster, here they are. The one on the left is NGC 4440 and the one on the right is NGC 4413.

Both pictures were taken with the same telescope and through the same filters, so we can really see some interesting differences between them. NGC 4440 is all yellow, and, as far as we can tell, totally devoid of any young stars or star formation.

NGC 4440 was once a galaxy very similar to NGC 1365. It had a strong bar (and it still does), and two long majestic spiral arms, and it still does. But when it was young and full of hot massive stars, it looked more wild and unkempt.

Note the bar-end enhancements in NGC 4440. Strongly barred galaxies often display an increased amount of star formation where the bar meets the arms. You can see a hint of increased star formation at the ends of the bar of NGC 1365, too.

Now all the bling and flashes and irregularities of NGC 4440 are gone, because all the massive young stars have died, and instead we can see the combined effect of billions of small old red stars making up the underlying highly symmetrical structure of the galaxy.




NGC 4413 is more like NGC 4725, in that its arms are pretty weak, and instead it is dominated by a star-forming ring. Actually though, the ring in NGC 4413 is made up of the two major arms, which overlap to seemingly form a ring.

Note the colors of NGC 4413. The outer arms are yellow and very fuzzy, so that they look more like a halo than two arms. But the inner parts of the arms, while also mostly yellow, are dotted with little knots of cyan. In SDSS photos, blue means young stars and green means red emission nebulas. The fact that the knots here are cyan suggests to me that not only do we see some young stars in NGC 4413, but we also see small amounts of ongoing star formation.

There is a big bright knot of cyan in the bar, "above" what must be the nucleus. That can only mean that a big cluster of bright blue stars have recently formed in the bar, and this cluster is still associated with some emission nebulosity.


Finally, take a look at this Hubble image of barred spiral galaxy NGC 1073. Look carefully, and you'll see that there is a bright region of bluish star formation in the bar, to the right of the nucleus.

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sun Oct 11, 2020 11:16 am

I'll try posting the amazing galaxy motion snippet as a picture instead of a video!


A 3D recreation of the real positions and images of galaxies in
the Universe as seen by the Sloan Digital Sky Survey (SDSS).
https://yt3.ggpht.com/GqqWmSoUg9UI04EBo ... 800-nd-rwa
Don't know about you, but I love it! 😃

Ann
Last edited by bystander on Sun Oct 11, 2020 1:58 pm, edited 1 time in total.
Reason: Please, no hot links to images > 500KB.
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by johnnydeep » Sun Oct 11, 2020 3:28 pm

Ann wrote:
Sun Oct 11, 2020 11:16 am
I'll try posting the amazing galaxy motion snippet as a picture instead of a video!


A 3D recreation of the real positions and images of galaxies in
the Universe as seen by the Sloan Digital Sky Survey (SDSS).
https://yt3.ggpht.com/GqqWmSoUg9UI04EBo ... 800-nd-rwa
Don't know about you, but I love it! 😃

Ann
Me too! I also found it as a true YouTube video here - https://www.youtube.com/watch?v=08LBltePDZw - for which embedding in a post still works. It's actually from 2012, so I wonder if there is newer data from the SDSS that would make a more "complete" video (though this is still pretty good as is :ssmile:)?
Click to play embedded YouTube video.
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by johnnydeep » Sun Oct 11, 2020 3:38 pm

Ann wrote:
Sun Oct 11, 2020 6:09 am
johnnydeep wrote:
Sun Oct 11, 2020 12:17 am
NCTom wrote:
Sat Oct 10, 2020 11:03 pm
I can see why the Virgo is such a favorite shot. There are two especially pretty barred spirals to the left of lower center adding to an already beautiful composition. Happy Birthday, Johnny.
I think you must mean these two? (from a higher res pic I found elsewhere*, here zoomed in and rotated) (Oh, and thanks!)
[(*) the original larger image is http://www.sun.org/uploads/images/Virgocluster.jpg]

99832F3A-25B8-4C1A-B690-54D8AAA20789.jpeg
Johnny, is it your birthday? Or was yesterday your birthday? In any case, congratulations!

<snip>

Ann
Yes, 10/10 is my B-day. And thanks for the extra "presents" about the other galaxies! (PS - your link to NGC 4725 was broken somehow - something about a permission issue)
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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by Ann » Sun Oct 11, 2020 3:39 pm

johnnydeep wrote:
Sun Oct 11, 2020 3:28 pm
Ann wrote:
Sun Oct 11, 2020 11:16 am
I'll try posting the amazing galaxy motion snippet as a picture instead of a video!


A 3D recreation of the real positions and images of galaxies in
the Universe as seen by the Sloan Digital Sky Survey (SDSS).
https://yt3.ggpht.com/GqqWmSoUg9UI04EBo ... 800-nd-rwa
Don't know about you, but I love it! 😃

Ann
Me too! I also found it as a true YouTube video here - https://www.youtube.com/watch?v=08LBltePDZw - for which embedding in a post still works. It's actually from 2012, so I wonder if there is newer data from the SDSS that would make a more "complete" video (though this is still pretty good as is :ssmile:)?
Click to play embedded YouTube video.
Thanks, Johnny, I love it! :D

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Re: APOD: Virgo Cluster Galaxies (2020 Oct 10)

Post by NCTom » Sun Oct 11, 2020 6:06 pm

Thanks for all the great stuff on the barred galaxies, people. You are a blessing.