APOD: NGC 247 and Friends (2018 Mar 30)

Comments and questions about the APOD on the main view screen.
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neufer
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Re: APOD: NGC 247 and Friends (2018 Mar 30)

Post by neufer » Sat Mar 31, 2018 2:09 pm

Ann wrote:
Sat Mar 31, 2018 6:03 am

... so the Burbidge's Chain galaxies are about 60,000 light-years apart. Actually, the distance between them will be a bit greater, since a parsec is a bit more than 3 light-years. Maybe the average distance between the Burbidge galaxies is 70,000 light-years. Same difference.

To put that distance in perspective, we may remember that the distance between the Milky Way and the Large Magellanic Cloud is ~160,000 light-years. And the Andromeda galaxy is about 2.5 million light-years away.

So the Burbidge's Chain galaxies live in close and neighborly proximity.
They are definitely relatively small though still interacting.

The ~70,000 light-years assumes that they are not accidentally lined up in our direction resulting in foreshortening.
Art Neuendorffer

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MarkBour
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Re: APOD: NGC 247 and Friends (2018 Mar 30)

Post by MarkBour » Mon Apr 02, 2018 2:01 am

starsurfer wrote:
Sat Mar 31, 2018 1:20 pm
Awesome image, it's so rare to see this field of view!

Some might find this paper interesting.
A bit advanced for me, but yes, I found it very interesting. Thanks!
Mark Goldfain

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Ann
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Re: APOD: NGC 247 and Friends (2018 Mar 30)

Post by Ann » Mon Apr 02, 2018 4:49 am

starsurfer wrote:
Sat Mar 31, 2018 1:20 pm
Awesome image, it's so rare to see this field of view!

Some might find this paper interesting.
Thanks, I found it very interesting! :D

What is clear from the paper is that the void is real, and that it is visible in all wavelengths from ultraviolet to infrared. It is also clear that the stars inside the void are older than the stars outside the void (there is even a sharp border), and there is a lack of Hα in the void. Voids are also found in other galaxies, but the void in NGC 247 is extremely large.

Possible causes of the void might be spiral density waves, or an interaction with a dark-matter-dominated subhalo.

Fascinating!

Ann
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Kaplaajohn

Re: APOD: NGC 247 and Friends (2018 Mar 30)

Post by Kaplaajohn » Mon Apr 02, 2018 3:18 pm

In this current picture.
is it me or at the lower left corner of this image.
To the right of a bright star.
Zoom in a lot and blown up the image.
Looks like 2 galaxies are being eaten buy a black hole?

JC

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Chris Peterson
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Re: APOD: NGC 247 and Friends (2018 Mar 30)

Post by Chris Peterson » Mon Apr 02, 2018 3:26 pm

Kaplaajohn wrote:
Mon Apr 02, 2018 3:18 pm
In this current picture.
is it me or at the lower left corner of this image.
To the right of a bright star.
Zoom in a lot and blown up the image.
Looks like 2 galaxies are being eaten buy a black hole?
Well, galaxies don't get eaten by black holes, so that can't be happening. If we're looking at the same place, it's just interacting galaxies, with a tidal tail of stars between them.
Chris

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