APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4409
Joined: Fri Dec 04, 2009 3:27 am

APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by APOD Robot » Tue Sep 07, 2021 4:06 am

Image NGC 520: Colliding Galaxies from Hubble

Explanation: Is this one galaxy or two? The jumble of stars, gas, and dust that is NGC 520 is now thought to incorporate the remains of two separate disk galaxies. A defining component of NGC 520 -- as seen in great detail in the featured image from the Hubble Space Telescope -- is its band of intricately interlaced dust running vertically down the spine of the colliding galaxies. A similar looking collision might be expected in a few billion years when our disk Milky Way Galaxy to collides with our large-disk galactic neighbor Andromeda (M31). The collision that defines NGC 520 started about 300 million years ago. Also known as Arp 157, NGC 520 lies about 100 million light years distant, spans about 100 thousand light years, and can be seen with a small telescope toward the constellation of the Fish (Pisces). Although the speeds of stars in NGC 520 are fast, the distances are so vast that the battling pair will surely not change its shape noticeably during our lifetimes.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
Ann
4725 Å
Posts: 11524
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Ann » Tue Sep 07, 2021 10:14 am

This is what Wikipedia wrote about NGC 520:


1) It is as bright in the infrared and radio bands as the Antennae Galaxies.

2) Simulations indicate this object consists of two galactic disks that began interacting about 300 million years ago.

3) In the X-ray band, the interacting galaxies appear around half as luminous as expected.

4) Analysis of the gas and molecular features suggests the secondary merger component is gas poor.

5) A large galactic wind is evident, being driven by the starburst activity.


A comparison between NGC 520 and NGC4038/NGC 4039 (the Antennae Galaxies) makes it immediately obvious that the Antennae galaxies are chock full of "clumps" of star clusters and nebulas, whereas such clumps are all but absent in NGC 520. In other words, the Antennae Galaxies are presently undergoing a starburst, whereas no signs of a starburst can easily be seen in NGC 520.

An aside here: By far most of the starburst of the Antennae Galaxies is taking place in just one of the colliding galaxies, NGC 4038 (the galaxy at top in the image). The other galaxy, NGC 4039, contributes little to the starburst.

As for NGC 520, much of its star formation ability may already be spent. Wikipedia said that one of the colliding components of NGC 520 was gas-poor, and presumably much of the gas in the other component has been used up. What we see is a rich population of bluish but moderate stars of spectral classes A and F, and only a few small clusters of hotter and more massive stars.

Yes, but Wikipedia spoke of a starburst in NGC 520! Where is that starburst located? There is only one answer: In one of the two nuclei.

The best-known example of a nuclear starburst is in nearby galaxy M82. Much like NGC 520, M82 displays virtually no signs at all of star formation in its disk. But its nucleus is a raging furnace of star formation and a furious galactic wind blowing from its nucleus.

There is apparently a nuclear starburst in one of the nuclei of NGC 520, too.

Ann
Color Commentator

User avatar
orin stepanek
Plutopian
Posts: 6821
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by orin stepanek » Tue Sep 07, 2021 12:17 pm

NGC520_HubbleOstling_960.jpg
Boy; these two really crashed! What a mess! :shock: Probably won't be
much left after the event :mrgreen:
.jpg
Oh; isn't he cute!
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

VictorBorun
Science Officer
Posts: 313
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by VictorBorun » Tue Sep 07, 2021 3:03 pm

You do not have the required permissions to view the files attached to this post.

VictorBorun
Science Officer
Posts: 313
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by VictorBorun » Tue Sep 07, 2021 3:23 pm

I think I can see a disk galaxy edge-on in the foreground, with a tail, and an elliptical galaxy in the background, with a tail
NGC 520 4.png
You do not have the required permissions to view the files attached to this post.

User avatar
Ann
4725 Å
Posts: 11524
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Ann » Tue Sep 07, 2021 4:26 pm

VictorBorun wrote:
Tue Sep 07, 2021 3:23 pm
I think I can see a disk galaxy edge-on in the foreground, with a tail, and an elliptical galaxy in the background, with a tail
Very interesting to see where you put the nuclei of the two galaxies, Victor! The starburst nucleus must be the one where you put your yellow cross. No way there is a starburst where the green cross is!

Ann
Color Commentator

VictorBorun
Science Officer
Posts: 313
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by VictorBorun » Tue Sep 07, 2021 5:03 pm

Ann wrote:
Tue Sep 07, 2021 4:26 pm
The starburst nucleus must be the one where you put your yellow cross.
Ann
I wonder if tails are tails. Might they be curving arm extentions that the two galaxies are reaching each other with?
Or if an elliptical galaxy can't have an arm extention — a curving protuberance?
I mean curving in planes we see edge-on, so we can't in fact see the curving

User avatar
Fred the Cat
Theoretic Apothekitty
Posts: 706
Joined: Mon Feb 22, 2016 4:09 pm
AKA: Ron
Location: Eagle, Idaho

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Fred the Cat » Tue Sep 07, 2021 5:37 pm

Pinpointing the source of high energy particles has been a mystery. Galaxy collisions seem like a possible source.:?: Cosmic rays zip into our world with mind-boggling energy. What two galactic collisions may create, imagine what three produce?

The study goes on but byproducts of these interactions stimulate my neurons. :thumb_up:
Freddy's Felicity "Only ascertain as a cat box survivor"

User avatar
Chris Peterson
Abominable Snowman
Posts: 16142
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Chris Peterson » Tue Sep 07, 2021 6:39 pm

Fred the Cat wrote:
Tue Sep 07, 2021 5:37 pm
Pinpointing the source of high energy particles has been a mystery. Galaxy collisions seem like a possible source.:?: Cosmic rays zip into our world with mind-boggling energy. What two galactic collisions may create, imagine what three produce?

The study goes on but byproducts of these interactions stimulate my neurons. :thumb_up:
Galaxy collisions are very low energy events. SMB mergers, however...
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


User avatar
neufer
Vacationer at Tralfamadore
Posts: 18362
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by neufer » Tue Sep 07, 2021 9:30 pm

APOD Robot wrote:
Tue Sep 07, 2021 4:06 am

Explanation: Also known as Arp 157, NGC 520 lies about 100 million light years distant, spans about 100 thousand light years, and can be seen with a small telescope toward the constellation of the Fish (Pisces). Although the speeds of stars in NGC 520 are fast, the distances are so vast that the battling pair will surely not change its shape noticeably during our lifetimes.
And here fantastic fishes duskly float,
Using the calm for waters, while their fires
Throb out quick rhythms along the shallow air.


— Elizabeth Barrett Browning, A Drama of Exile
Art Neuendorffer

VictorBorun
Science Officer
Posts: 313
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by VictorBorun » Tue Sep 07, 2021 9:58 pm

here is another pic from the same article overlayed with the posted pic.
Had to rotate this one 2.5° clockwise; it was not precisely matching the first pic.
NGC 520 5.png
You do not have the required permissions to view the files attached to this post.

VictorBorun
Science Officer
Posts: 313
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by VictorBorun » Tue Sep 07, 2021 10:13 pm

johnnydeep wrote:
Tue Sep 07, 2021 8:05 pm
This looks familiar...
A chromosome has a little bridge between ⟩ and ⟨ making a figure like ⟩⟨
Now NGC 520 has an X-ray visible plasma wind from the core of the foreground disk galaxy toward the middle of the long protuberance reaching out of the background elliptic galaxy. Can count as a brigde…

User avatar
Fred the Cat
Theoretic Apothekitty
Posts: 706
Joined: Mon Feb 22, 2016 4:09 pm
AKA: Ron
Location: Eagle, Idaho

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Fred the Cat » Wed Sep 08, 2021 1:20 am

You do not have the required permissions to view the files attached to this post.
Freddy's Felicity "Only ascertain as a cat box survivor"

User avatar
Fred the Cat
Theoretic Apothekitty
Posts: 706
Joined: Mon Feb 22, 2016 4:09 pm
AKA: Ron
Location: Eagle, Idaho

Re: APOD: NGC 520: Colliding Galaxies from Hubble (2021 Sep 07)

Post by Fred the Cat » Thu Sep 09, 2021 4:44 pm

Chris Peterson wrote:
Tue Sep 07, 2021 6:39 pm
Fred the Cat wrote:
Tue Sep 07, 2021 5:37 pm
Pinpointing the source of high energy particles has been a mystery. Galaxy collisions seem like a possible source. Cosmic rays zip into our world with mind-boggling energy. What two galactic collisions may create, imagine what three produce?

The study goes on but byproducts of these interactions stimulate my neurons. :thumb_up:
Galaxy collisions are very low energy events. SMB mergers, however...
Seems we get new news every day about the unexpected. :ssmile: I have to admire those who comb through data to find things to look for in the universe. :clap:
Freddy's Felicity "Only ascertain as a cat box survivor"