Page 1 of 1

APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 4:05 am
by APOD Robot
Image NGC 3521: Galaxy in a Bubble

Explanation: Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65. It's hard to overlook in this colorful cosmic portrait, though. Spanning some 50,000 light-years the galaxy sports characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past.

<< Previous APODDiscuss Any APOD Next APOD >>
[/b]

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 4:48 am
by Boomer12k
AAAAARRRRRGGGGHHHHHH, Matey, there be TREASURE THERE.....X MARKS THE SPOT!!!!


:--------======== *

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 6:08 am
by nstahl
Another beautiful image, another great APOD.

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 7:49 am
by Ann
This is another wonderful galaxy portrait by master astrophotographer R. Jay GaBany. Congratulations to David Martinez-Delgado, too, for your collaboration.

The bright yellow swirling star clouds above the bulge of NGC 3521 are interesting. While I have never seen them more clearly than in this picture, other images have also revealed at least traces of them, and their very yellow color has usually been brought out as well. So there can be no doubt that these star clouds are real, nor the fact that they must be composed of old metal-rich stars.

That in itself is interesting. APOD robot wrote:
The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past.
Image
Yes, that seems quite probable. On the other hand, the very yellow color of the stars above the bulge of NGC 3521 is confusing here. If this galaxy has swallowed a member of the menagerie of dwarf lenticular galaxies, which are composed of old metal-poor stars, the star clouds that resulted from swallowing one of these galaxies ought to be fairly neutral-colored. A prime example of the appearance of old metal-poor stars would be the stars of Omega Centauri, the brightest globular cluster of the Milky Way, which may well be the nucleus of a dwarf galaxy that has been incorporated into the Milky Way.


Stars of Omega Centauri, photographed by the Hubble Space Telescope.

Check out this image of Omega Centauri and its surroundings, where the globular cluster looks quite blue.


Image

The star clouds above the bulge of NGC 3521 might possibly result from the swallowing of a small metal-rich galaxy composed entirely of old stars. A prime example might be M32, the small, compact, very yellow companion galaxy of M31. This is an image of M32 and "friends", including "bully" M31, taken by the Canada-France-Hawaii Telescope.






Ann

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 8:55 am
by Case
Ann wrote:The bright yellow swirling star clouds above the bulge of NGC 3521 are interesting. While I have never seen them more clearly than in this picture, other images have also revealed at least traces of them
This image brings out the tidal debris so much, that it made me wonder why so much matter hasn't made more (visual) distortion the main galaxy; the spiral arms look quite regular and tidy. One speculation of mine is that perhaps the bubble is made of part satellite galaxies and part of NGC 3521 itself. Like much of the distortion is "up-down" with regard to the disc, while leaving the structure of the spiral arms intact. Does that seem plausible?

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 9:13 am
by Ann
Case wrote:
Ann wrote:The bright yellow swirling star clouds above the bulge of NGC 3521 are interesting. While I have never seen them more clearly than in this picture, other images have also revealed at least traces of them
This image brings out the tidal debris so much, that it made me wonder why so much matter hasn't made more (visual) distortion the main galaxy; the spiral arms look quite regular and tidy. One speculation of mine is that perhaps the bubble is made of part satellite galaxies and part of NGC 3521 itself. Like much of the distortion is "up-down" with regard to the disc, while leaving the structure of the spiral arms intact. Does that seem plausible?
You mean, has something odd been going on in or near the nucleus of NGC 3521? I was wondering about that myself. But NGC 3521 can't have a very active nucleus, because then astronomer would be well aware of that fact, and I'm sure that the caption of today's APOD would tell us so, too.

Ann

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 9:28 am
by 500pesos
Another fantastic image today; truly we're being spoiled by APOD ;)

I don't know if it's me but the NGC's 3521 spiral arms don't look distorted.
As for the yellowish colour of the bulge in the middle, if it is remnants from former lenticular galaxies absorbed by NGC 3521, it seems right to me. Most lenticular galaxies I've seen are yellowish, because there is no new star formation going on and the age of most of the galaxy's stars is advanced (hence the yellow-orangey colour).

Of course, something more exciting could be going on there ... (treasure, etc.)
Are there images of NGC 3521 in other wavelengths than visual light?

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 9:39 am
by pedro melo
I wonder how would the night sky appear to some one living in a planet surrounding a star in the tidal debris above NGC 3521 plane?
Instead of a edge on view like the one we have of the milkyway, would it be a full galaxy view?

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 10:07 am
by owlice
nstahl wrote:Another beautiful image, another great APOD.
Yes!!

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 10:26 am
by bystander
Ann wrote:The bright yellow swirling star clouds above the bulge of NGC 3521 are interesting. While I have never seen them more clearly than in this picture, other images have also revealed at least traces of them
Case wrote:This image brings out the tidal debris so much, that it made me wonder why so much matter hasn't made more (visual) distortion the main galaxy; the spiral arms look quite regular and tidy. One speculation of mine is that perhaps the bubble is made of part satellite galaxies and part of NGC 3521 itself. Like much of the distortion is "up-down" with regard to the disc, while leaving the structure of the spiral arms intact. Does that seem plausible?
Ann wrote:You mean, has something odd been going on in or near the nucleus of NGC 3521? I was about that myself. But NGC 3521 can't have a very active nucleus, because then astronomer would be well aware of that fact, and I'm sure that the caption of today's APOD would tell us so, too.
It might be something like this new study on the origin of the Milky Way's spiral.

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 11:54 am
by orin stepanek
This beautiful galaxy seems to have more than it's share of dust. It ought to be busy making stars for eons to come. 8-)

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 11:58 am
by neufer
orin stepanek wrote:
This beautiful galaxy seems to have more than it's share of dust.
It ought to be busy making stars for eons to come. 8-)
<<Schmutz (Shmoots): a Yiddish word for dirt, or mud or some such stuff.

If you just ate a cream doughnut you might have some schmutz on your shirt where the cream fell out.>>[/quote]

Colors

Posted: Thu Sep 15, 2011 1:18 pm
by Geoffrey
A quick comment, it would be nice if the APOD picture captions mentioned what the colors are, and whether they are stetched, particular since many images are out of the visual spectrum and the colors are assigned. This image looks to me like stretched true color?

Re: Colors

Posted: Thu Sep 15, 2011 1:38 pm
by Chris Peterson
Geoffrey wrote:A quick comment, it would be nice if the APOD picture captions mentioned what the colors are, and whether they are stetched, particular since many images are out of the visual spectrum and the colors are assigned. This image looks to me like stretched true color?
APOD captions generally only give the imaging details when they are particularly relevant. The caption almost always includes a link to the original image, where that information can be obtained. In this case the image is LRGB, which means it is "true" color, although that term is pretty ill defined. All astronomical images are contrast stretched, or we'd see practically nothing in them.

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 1:40 pm
by Chris Peterson
pedro melo wrote:I wonder how would the night sky appear to some one living in a planet surrounding a star in the tidal debris above NGC 3521 plane?
Instead of a edge on view like the one we have of the milkyway, would it be a full galaxy view?
Yes, but that full galaxy view would basically look like the Milky Way, just spread out over the sky instead of in a band. That might make it less apparent and impressive than the Milky Way- just a slightly structured background glow across the entire sky.

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Sep 15, 2011 11:33 pm
by saturn2
This is a beautiful bubble in the space.
Distance from Earth to NGC 3521 35 million light- years.
I think that NGC 3521 is a galaxy very compact and very bright.

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Sat Sep 17, 2011 12:24 am
by NoelC
Not all viewers may be seeing the dim bubble-like structures around these galaxies, because not all monitors respond equally to darker pixels.

Here's a slightly lightened version to help people more easily see into the dark...
Lighter version of the APOD
Lighter version of the APOD
-Noel

Re: APOD: NGC 3521: Galaxy in a Bubble (2011 Sep 15)

Posted: Thu Jan 26, 2012 5:53 pm
by bystander
The Formation and Evolution of Galaxies
Cosmotography | R. Jay GaBany

NGC 3521, The Bubble Galaxy
Cosmotography | R. Jay GaBany

Stellar Tidal Streams in Spiral Galaxies of the Local Volume: A Pilot Survey with Modest Aperture Telescopes - David Martínez-Delgado et al