Starship Asterisk*

[quote="starsurfer"][quote="Ann"]Nice! :D NGC 660 is one of the classic polar ring galaxies. Today's APOD is a very nice portrait of it!

[float=left][img2]http://tinyurl.com/h6srpqm[/img2][c][size=80]Mayall's Object, also known as Arp 148.
It is one of the truly weird polar ring galaxies.
Photo: NASA, ESA, the Hubble Heritage-ESA/
Hubble Collaboration, and A. Evans [/size][/c][/float] At left, as you can see, is a truly weird polar ring galaxy, Mayall's Object or Arp 148.

Ann[/quote]
Isn't this a collisional ring galaxy? [/quote]

You're right, starsurfer, but it looks like a polar ring galaxy, in any case.

[float=left][img]https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/NGC_2685.jpg/300px-NGC_2685.jpg[/img][c][size=85]NGC 2685,
Photo: Ken Crawford.[/size][/c][/float] Another classic polar ring galaxy is NGC 2685. Full size image is [url=https://apod.nasa.gov/apod/ap140314.html]here[/url].

Ann

This is the first I have heard of polar ring galaxies or seen a picture. I have been checking APOD pretty much daily since 2002 or so. Don't know how I missed them for so long. Quite spectacular.

[quote="starsurfer"]What I find surprising about this amazing image is the number of HII regions visible without hydrogen alpha exposures![/quote]
Why? We see HII regions all the time in RGB galaxy images, given that they are typically the dominant source of red light. It's in nebulas, where other emission lines are also strong and where there is much more reflected white light that Ha filters tend to really emphasize HII structure.

What I find surprising about this amazing image is the number of HII regions visible without hydrogen alpha exposures! Also the two galaxies near the bottom left corner are 760 million light years away!

[quote="Ann"]Nice! :D NGC 660 is one of the classic polar ring galaxies. Today's APOD is a very nice portrait of it!

[float=left][img2]http://tinyurl.com/h6srpqm[/img2][c][size=80]Mayall's Object, also known as Arp 148.
It is one of the truly weird polar ring galaxies.
Photo: NASA, ESA, the Hubble Heritage-ESA/
Hubble Collaboration, and A. Evans [/size][/c][/float] At left, as you can see, is a truly weird polar ring galaxy, Mayall's Object or Arp 148.

Ann[/quote]
Isn't this a collisional ring galaxy? Another polar ring galaxy is [url=https://www.spacetelescope.org/images/opo9916a/]NGC 4650A[/url].

Well done! The image is full of other galaxies. In the lower left, the edge-on and the blue galaxies are impressive.
Dave.

WOW IT's fantastic image!!!

[quote="Ann"]Nice! :D NGC 660 is one of the classic polar ring galaxies. Today's APOD is a very nice portrait of it!

[float=left][img2]http://tinyurl.com/h6srpqm[/img2][c][size=80]Mayall's Object, also known as Arp 148.
It is one of the truly weird polar ring galaxies.
Photo: NASA, ESA, the Hubble Heritage-ESA/
Hubble Collaboration, and A. Evans [/size][/c][/float] At left, as you can see, is a truly weird polar ring galaxy, Mayall's Object or Arp 148.

Ann[/quote]

Cool one, Ann!!!

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Nice! :D NGC 660 is one of the classic polar ring galaxies. Today's APOD is a very nice portrait of it!

[float=left][img2]http://tinyurl.com/h6srpqm[/img2][c][size=80]Mayall's Object, also known as Arp 148.
It is one of the truly weird polar ring galaxies.
Photo: NASA, ESA, the Hubble Heritage-ESA/
Hubble Collaboration, and A. Evans [/size][/c][/float] At left, as you can see, is a truly weird polar ring galaxy, Mayall's Object or Arp 148.

Ann

[url=https://apod.nasa.gov/apod/ap170217.html][img]https://apod.nasa.gov/apod/calendar/S_170217.jpg[/img] [size=150]Polar Ring Galaxy NGC 660[/size][/url]

[b] Explanation: [/b] NGC 660 is featured in [url=http://chart32.de/index.php/component/k2/item/234]this cosmic snapshot[/url]. Over 40 million light-years away and swimming within the boundaries of the [url=http://en.wikipedia.org/wiki/Pisces_(constellation)]constellation Pisces[/url], NGC 660's peculiar appearance marks it as [url=https://apod.nasa.gov/apod/ap070216.html]a polar ring galaxy[/url]. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust [url=https://arxiv.org/abs/astro-ph/0404286]orbiting in rings[/url] strongly tilted from the plane of the galactic disk. [url=http://arxiv.org/abs/astro-ph/0301391]The bizarre-looking configuration[/url] could have been caused by the chance capture of material from a passing galaxy by a disk galaxy, with the captured debris eventually strung out in a rotating ring. The violent gravitational interaction would account for the myriad pinkish star forming regions scattered along NGC 660's ring. [url=http://www.obspm.fr/polar-ring-galaxies-and-dark-matter.html?lang=en]The polar ring component[/url] can also be used to explore the shape of the galaxy's otherwise unseen dark matter halo by calculating the [url=http://chandra.harvard.edu/xray_astro/dark_matter/index.html]dark matter's[/url] gravitational influence on the rotation of the ring and disk. Broader than the disk, NGC 660's ring spans over 50,000 light-years.

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