Starship Asterisk*

Arp 273: Battling Galaxies from Hubble

Explanation: What's happening to these spiral galaxies? Although details remain uncertain, there sure seems to be a titanic battle going on. The upper galaxy is labelled UGC 1810 by itself, but together with its collisional partners is known as Arp 273. The overall shape of the UGC 1810 -- in particular its blue outer ring -- is likely a result of wild and violent gravitational interactions. The blue color of the outer ring at the top is caused by massive stars that are blue hot and have formed only in the past few million years. The inner part of the upper galaxy -- itself an older spiral galaxy -- appears redder and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to colliding galaxies, while several far-distant galaxies are visible in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekicks over the next billion years and settle into a classic spiral form.

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Arp 273 is certainly one of the most photogenic and fascinating of interacting galaxy pairs.

Take a look at the small "maelstrom" in the blue arm at far right. Doesn't it look as if this is a small galaxy in itself, and doesn't it appear to be the very source of many of the brilliant blue star clusters in that spiral arm? Utterly fascinating, if you ask me. I would so like to know if that really is a galaxy, and if it really is the source of much of the star formation in UGC 1810!

Note the rather ugly photographic defect near a bright blue-white foreground star seen very close to the center of UGC 1810. Those two orange "rings" to the upper right of that star mar the image, in my opinion.

Otherwise it is a great image!

I have no idea what was the problem with the background starfield of the original Hubble image... Mr. Pohl might have had problems with it as he replaced it with many identical parts of the original image stamping them across the picture... Even a 1 minute check would reveal many of them, e.g. there's a small galaxy that appears at least 5 times at different places, there's a cluster of 2 galaxies and a red start which appear 3 times, there're parts which appear 7 times...

Sometimes processing...bringing out details, with Contrast or Levels in a photo, can also bring out the Artifacts, from the lens of the camera...there are less in the other photo which is a bit darker, in Ann's comparison.

Sometimes to bring out details, or brightness, the background lens defects can appear.
You can see with my M27 Dumbbell images the difference between the original "dingy" image and the processed brighter image. Contrast, Level, Colors brought out, but the stars are more overexposed.

:---[===] *

Good points and good comparison, Boomer.

Ann

Hello,
Incredible image, so much to see. I wish I could zoom in some of the features one can see. Can somebody tell me what is the sphere-like structure with two layers located below and right of the center of UGC 1810?
Thanks!!

Rather than discuss the techncal imaging details, may I ask for a discussion of Ann's other point?

Ann wrote: ↑Wed Nov 20, 2019 6:31 am Take a look at the small "maelstrom" in the blue arm at far right. Doesn't it look as if this is a small galaxy in itself, and doesn't it appear to be the very source of many of the brilliant blue star clusters in that spiral arm? Utterly fascinating, if you ask me. I would so like to know if that really is a galaxy, and if it really is the source of much of the star formation in UGC 1810!

And I would add to that the formation at about 4 o'clock on the main, UGC 1810 disc. Is it part of that galaxy, or nearer and superimposed? What is it?
JOhn

Bugui wrote: ↑Wed Nov 20, 2019 10:03 am Hello,
Incredible image, so much to see. I wish I could zoom in some of the features one can see. Can somebody tell me what is the sphere-like structure with two layers located below and right of the center of UGC 1810?
Thanks!!

You mean this one?

It's a background spiral galaxy, seen face on. It is much farther away than UGC 1810.

Thank you, Ann! It appeared to have a 'wake' through the spiral arm it is - I now know - infraimposed on.
JOhn

Ann wrote: ↑Wed Nov 20, 2019 6:31 am Arp 273 is certainly one of the most photogenic and fascinating of interacting galaxy pairs.

Take a look at the small "maelstrom" in the blue arm at far right. Doesn't it look as if this is a small galaxy in itself, and doesn't it appear to be the very source of many of the brilliant blue star clusters in that spiral arm? Utterly fascinating, if you ask me. I would so like to know if that really is a galaxy, and if it really is the source of much of the star formation in UGC 1810!

Note the rather ugly photographic defect near a bright blue-white foreground star seen very close to the center of UGC 1810. Those two orange "rings" to the upper right of that star mar the image, in my opinion.

Otherwise it is a great image!


Small galaxy in UGC 1810.png

I see these; and a lot of far away galaxies! whether some are behind or part of the main galaxy; i have no clue!

orin stepanek wrote: ↑Wed Nov 20, 2019 11:26 am

Ann wrote: ↑Wed Nov 20, 2019 6:31 am Arp 273 is certainly one of the most photogenic and fascinating of interacting galaxy pairs.

Take a look at the small "maelstrom" in the blue arm at far right. Doesn't it look as if this is a small galaxy in itself, and doesn't it appear to be the very source of many of the brilliant blue star clusters in that spiral arm? Utterly fascinating, if you ask me. I would so like to know if that really is a galaxy, and if it really is the source of much of the star formation in UGC 1810!

Note the rather ugly photographic defect near a bright blue-white foreground star seen very close to the center of UGC 1810. Those two orange "rings" to the upper right of that star mar the image, in my opinion.

Otherwise it is a great image!


Small galaxy in UGC 1810.png

I see these; and a lot of far away galaxies! whether some are behind or part of the main galaxy; i have no clue! Arp273_HubblePohl_960.jpg

Thanks, Orin, for drawing circles and ellipses around interesting features in today's APOD. I have no idea how to do that!

As to what objects are in the foreground and in the background: The stars, the bright point sources, are in the foreground, and the small extended objects are background galaxies!

Ann

Ann; there is a lot about windows Microsoft paint! I don't know your system; but maybe this would help! Good luck with it!

https://www.wikihow.com/Use-Microsoft-Paint-in-Windows

orin stepanek wrote: ↑Wed Nov 20, 2019 12:33 pm Ann; there is a lot about windows Microsoft paint! I don't know your system; but maybe this would help! Good luck with it!

https://www.wikihow.com/Use-Microsoft-Paint-in-Windows

Thanks, Orin! I'll try it... later... (alligator)

LazyAnn

Is there a supernova remnant near the bright star in the upper center of the image?

Devil Particle wrote: ↑Wed Nov 20, 2019 1:20 pm Is there a supernova remnant near the bright star in the upper center of the image?

To me that mystery object resembles a foreground planetary nebula, but comments of Ann and others and especially the comparison shot she provided makes me think that this is nothing but a photographic and/or processing error. If so I agree that it is a marred image.

It really brings out the large-scale size of the universe when we can see dozens of tiny splotches of far background galaxies, and the one we're looking at is 300 million light-years away.

By citing the subject of today's APOD as being 300 million light years distant dismisses the fact that what is being analysed is 300 million years old. Without qualifying the time difference, the validity of the visual analysis is suspect. Furthermore, with a delay extant throughout the Universe that has
only been graphically illustrated relatively recently by Hubble, why are we not acknowledging the missing time variable?
Perhaps when the Universe was deemed smaller, the Now was dominant. Today, however, events not labelled as past are misinterpreting reality and ignoring significant evolution.

DL MARTIN wrote: ↑Wed Nov 20, 2019 5:23 pm By citing the subject of today's APOD as being 300 million light years distant dismisses the fact that what is being analysed is 300 million years old. Without qualifying the time difference, the validity of the visual analysis is suspect. Furthermore, with a delay extant throughout the Universe that has
only been graphically illustrated relatively recently by Hubble, why are we not acknowledging the missing time variable?
Perhaps when the Universe was deemed smaller, the Now was dominant. Today, however, events not labelled as past are misinterpreting reality and ignoring significant evolution.

No. What is being analyzed is the galaxies at a certain point in their evolution. Now. That's all that matters. The distance is relevant only to issues such as how the wavelength has changed during the time of flight. It isn't relevant to the nature of the collision or the structure of the galaxies at all.

BDanielMayfield wrote: ↑Wed Nov 20, 2019 1:45 pm

Devil Particle wrote: ↑Wed Nov 20, 2019 1:20 pm Is there a supernova remnant near the bright star in the upper center of the image?

To me that mystery object resembles a foreground planetary nebula, but comments of Ann and others and especially the comparison shot she provided makes me think that this is nothing but a photographic and/or processing error. If so I agree that it is a marred image.

Something that I noticed when I had a chance to look at this APOD image on a larger display cinched the case that this is an artifact. If you also look at the very bright foreground star on the left edge of the galaxy you can see another (although dimmer) double ring effect.

BDanielMayfield wrote: ↑Wed Nov 20, 2019 6:43 pm Something that I noticed when I had a chance to look at this APOD image on a larger display cinched the case that this is an artifact. If you also look at the very bright foreground star on the left edge of the galaxy you can see another (although dimmer) double ring effect.

And if you draw lines through their centres, they meet towards the middle of the image. If there was a third one at the bottom of the picture, it would point up towards the meeting point. It's a multiple internal reflection artifact inside the camera lens (not the telescope itself).

TheOtherBruce wrote: ↑Wed Nov 20, 2019 7:18 pm

BDanielMayfield wrote: ↑Wed Nov 20, 2019 6:43 pm Something that I noticed when I had a chance to look at this APOD image on a larger display cinched the case that this is an artifact. If you also look at the very bright foreground star on the left edge of the galaxy you can see another (although dimmer) double ring effect.

And if you draw lines through their centres, they meet towards the middle of the image. If there was a third one at the bottom of the picture, it would point up towards the meeting point. It's a multiple internal reflection artifact inside the camera lens (not the telescope itself).

So you have (gasp) uncovered another defect with Hubble???

Ann wrote: ↑Wed Nov 20, 2019 6:31 am
Note the rather ugly photographic defect near a bright blue-white foreground star seen very close to the center of UGC 1810. Those two orange "rings" to the upper right of that star mar the image, in my opinion.

If you don't look too closely at that feature, it looks more like a boxing glove one of the galaxies is using to punch another!

Oops! It looks like I don't have the boxing glove emoji available!
B^)

Devil Particle wrote: ↑Wed Nov 20, 2019 1:20 pm Is there a supernova remnant near the bright star in the upper center of the image?

No. The orange ring structure is a photographic artefact, caused by reflections in the camera lens from the bright star.

Ann

TheZuke! wrote: ↑Wed Nov 20, 2019 9:42 pm

Ann wrote: ↑Wed Nov 20, 2019 6:31 am
Note the rather ugly photographic defect near a bright blue-white foreground star seen very close to the center of UGC 1810. Those two orange "rings" to the upper right of that star mar the image, in my opinion.

If you don't look too closely at that feature, it looks more like a boxing glove one of the galaxies is using to punch another!

Oops! It looks like I don't have the boxing glove emoji available!
B^)

This picture is kind of big, but I like it. Tussling yellow emoji - I mean galaxies - show off their blows!

Ann