APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4779
Joined: Fri Dec 04, 2009 3:27 am

APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by APOD Robot » Thu May 05, 2022 4:05 am

Image NGC 3521: Galaxy in a Bubble

Explanation: Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the northern springtime 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. This deep image also finds NGC 3521 embedded in fainter, 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 APOD This Day in APOD Next APOD >>

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1514
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by JohnD » Thu May 05, 2022 8:05 am

This pic shows especially well that a galaxy isn't a neat and tidy spiral. Many pics of other galaxies suggest a cloud of stars, relatively disorganised, around the main structure, but not as clearly as this. So the Milky Way will have a shell of stars. Do we know this, or only infer it?

John

User avatar
XgeoX
Science Officer
Posts: 212
Joined: Tue Jun 30, 2020 12:57 pm
AKA: Uncle Rico

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by XgeoX » Thu May 05, 2022 9:22 am

JohnD wrote: Thu May 05, 2022 8:05 am This pic shows especially well that a galaxy isn't a neat and tidy spiral. Many pics of other galaxies suggest a cloud of stars, relatively disorganised, around the main structure, but not as clearly as this. So the Milky Way will have a shell of stars. Do we know this, or only infer it?

John
We know it as they have been directly observed…
Milky Way Leftover Shell Stars Discovered In Galactic Halo
Like tantalizing tidbits stored in the vast recesses of one’s refrigerator, astronomers using NASA’s Hubble Space Telescope have evidence of a shell of stars left over from one of the Milky Way’s meals. In a study which will appear in an upcoming issue of the Astrophysical Journal researchers have revealed a group of stars moving sideways – a motion which points to the fact our galaxy may have consumed another during its evolution.

“Hubble’s unique capabilities are allowing astronomers to uncover clues to the galaxy’s remote past. The more distant regions of the galaxy have evolved more slowly than the inner sections. Objects in the outer regions still bear the signatures of events that happened long ago,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

As curious as this shell of stars is, they offer even more information by revealing a chance to study the mysterious hidden mass of Milky Way – dark matter. With more than a hundred billion galaxies spread over the Universe, what better place to get a closer look than right here at home? The team of astronomers led by Alis Deason of the University of California, Santa Cruz, and van der Marel studied the outer halo, a region roughly 80,000 light years from our galaxy’s center, and identified 13 stars which may have come to light at the very beginning of the Milky Way’s formation.
Image
https://www.universetoday.com/100158/m ... ctic-halo/
Star Map of the Milky Way's Outer Halo
Image
Images of the Milky Way and the Large Magellanic Cloud (LMC) are overlaid on a map of the surrounding area, our galaxy's galactic halo. Dark blue represents a low concentration of stars; lighter blues indicate increasing stellar density. The map spans from about 200,000 light-years to 325,000 light-years from the galactic center and provides the first clear view of the major features in this region.

The LMC is orbiting the Milky Way and will eventually merge with it. The high concentration in the lower half is a wake created by the LMC as it sails through the galactic halo.

In the upper half of the image, astronomers observed an apparent excess of stars compared to the southern hemisphere. This is evidence that the Large Magellanic Cloud has pulled the Milky Way disk significantly off-center. The galactic halo can be thought of as a bubble surrounding the disk. The number of stars per area is highest near the center of the bubble, and drops off moving away from the center. If the Milky Way were in the center of the halo, astronomers would see an approximately equal number of stars in both hemispheres. But because the Milky Way has been pulled away from the center, when astronomers look into the northern hemisphere, they see more of the central, highly populated area. Comparing these two views, there is an apparent excess of stars in the northern hemisphere.
https://www.jpl.nasa.gov/images/pia2457 ... outer-halo
Ancient Halo Stars Cast the Milky Way’s First Light
We inhabit a giant spiral-shaped galaxy that glows with hundreds of billions of stars, a colossus so massive that at least two dozen lesser galaxies revolve around it. But how did this enormous entity arise? Clues come from the Milky Way's oldest and wisest stars—those in the stellar halo, the galactic component that envelops the bright disk housing the sun.
Halo stars stand out because they formed before supernova explosions had scattered a large amount of heavy elements into the galaxy, so halo stars possess little iron. The brightest halo members are iron-poor globular star clusters, spectacular objects that can pack hundreds of thousands of old stars into a sphere just a few dozen light-years across.
Now the Hubble Space Telescope has found that an individual halo star is even older than these ancient star cities and is thus an ideal time capsule passed down from the Milky Way's birth. "This is a really elegant piece of work," says Gerry Gilmore, an astronomer at the University of Cambridge in England who was not affiliated with the researchers. "They've done as good a job as it is possible to do."

Despite its importance, the stellar halo constitutes just a thousandth of the Milky Way's total mass. Although the halo extends far beyond the disk, most of its stars lie closer to the galaxy's center than we do, so globular clusters abound in constellations toward the galactic center, such as Scorpius and Sagittarius.
https://www.scientificamerican.com/art ... rst-light/
Image

As Johnny Carson might say “that is some wild, weird stuff!”

Eric
Ego vigilate
Ego audire

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1514
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by JohnD » Thu May 05, 2022 9:51 am

Thank you, XgeoX!

The idea of primitive, hill-billy stars out in the boondocks is intriguing! When looking at a galaxy's portrait, I always wonder what the view would be in a planet's sky, and if there might be anyone to see it. From what you say, despite the age of halo stars, the lack of heavy elements may make life less likely.
John

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Ann » Thu May 05, 2022 9:57 am

I like this picture of stellar streams orbiting the Milky Way. I couldn't help drawing dots along the streams to make them stand out more in the picture at left. In the picture at right, you can see some of the dwarf galaxies that have "donated" the streams of stars that are orbiting our galaxy.

Stellar streams northern sky SDSS Ana Bonaca.png
Several stellar streams orbiting the Milky Way.
Image: SDSS/Ana Bonaca.
Stellar streams and their remnant dwarf galaxies SDSS Vasily Belokurov Roen Kelly.png
Stellar streams and their remnant dwarf galaxies.
Image: SDSS/Vasily Belokurov/Roen Kelly.

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

User avatar
orin stepanek
Plutopian
Posts: 7722
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by orin stepanek » Thu May 05, 2022 12:00 pm

NGC3521LRGBHaAPOD-20_1024.jpg
Kinda looks as though it is in a cloud;or bubble as the title says! 8-)
Maybe the Galaxy is still growing; what with al the fodder around it!
Beautiful; isn't it! 🤩
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

rwlott
Ensign
Posts: 32
Joined: Fri May 06, 2011 7:05 pm

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by rwlott » Thu May 05, 2022 12:27 pm

Image

Russ

p1gnone
Ensign
Posts: 11
Joined: Fri May 18, 2007 12:15 am

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by p1gnone » Thu May 05, 2022 3:31 pm

more than enveloped in a bubble there appears a distinctly red column, obliquely aimed at the galactic center to the left, ad perhaps from behind also to the right. Is this a anomaly of the imaging or active galactic center ? M82 has messy jets, and the artists conceive columnar jets always orthogonal to galactic plane. So is this a galactic feature or am I imagining too much?

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Ann » Thu May 05, 2022 3:38 pm


NGC 3521 is a fascinating galaxy, and today's APOD is very fine. Please compare the Hanson/Selby image with the one by R. Jay GaBany at right. Note how "thick" the yellow streams are, and how they seem to rise from the central part of the galaxy like "smoke". This sort of thing isn't "normal", or at least, it isn't at all common. It's not the streams themselves that are unusual, but their brightness is.

For myself, I find the streams' deep yellow-orange color remarkable, too. Streams usually originate from dwarf galaxies that have been captured by a larger galaxy and have been cannibalized by the larger bully. But dwarf galaxies, even those that consists of old stars only, aren't usually so red. That's because dwarf galaxies tend to be relatively metal-poor, and metal-poor stars are a little bluer (or more non-red) than metal-rich ones at the same spectral class and temperature.

Note in the Hanson/Selby image that one of the yellow streams seems to contain a truly red component too, as if it contained some ionized hydrogen. It would be interesting if that was the case.

To me the yellow streams rising from the center of NGC 3521 appear somewhat similar to water splashing from a pond when you have thrown a stone into it. Is it possible that something similar is going on in NGC 3521? Can the yellow stars of the streams actually be yellow stars from the bulge of NGC 3521 itself that are "splashing" from center because something has been "thrown" into it? (I can hear Chris say no. :wink: Because when a galaxy hits another galaxy the result looks like, say, the Tadpole galaxy, not like water splashing from a pond.)


I keep insisting that the shells of NGC 3521 are unusually yellow. Let's compare it with two shell galaxies in Pisces, NGC 474 and NGC 467:


In my opinion, Martin Pugh's image has a bluish cast to it, which is to say that I believe that the shells of NGC 474 are probably not as bluish as they appear to be here. On the other hand, we can say without a doubt that the shells of NGC 474 are bluer than the yellow core of NGC 474, and I'm not sure that the same thing can be said about NGC 3521. In other words, the shells of NGC 3521 appear to be the same deep yellow color as the core of this galaxy.

The shells of NGC 467 appears to be a little yellower than the shells of NGC 474, but still not as yellow as the shells of NGC 3521.

Read about NGC 474 here.

Ann
Color Commentator

Tekija

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Tekija » Thu May 05, 2022 9:28 pm

Ann: from the apod link:

”Also, notice the rarely seen Hydrogen Alpha jets emanation from this galaxy.”

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by VictorBorun » Fri May 06, 2022 9:50 am

red alpha Hydrogen jet? Yellow stellar chimney?
Let's try to fit the two images.
100% Hanson+Selby.jpg
67% Hanson+Selby.jpg
0% Hanson+Selby.jpg
You do not have the required permissions to view the files attached to this post.

Iaffaldano Giuseppe Carmine
Ensign
Posts: 54
Joined: Sun Jun 18, 2017 10:13 am
Location: TARANTO

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Iaffaldano Giuseppe Carmine » Tue May 10, 2022 6:25 am


User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Ann » Tue May 10, 2022 8:15 am

Iaffaldano Giuseppe Carmine wrote: Tue May 10, 2022 6:25 am at least you could change the title...... see my post and my picture of 03/02/2020

https://www.flickr.com/photos/17910585@ ... 167213281/

ImageNgc 3521 Galaxy - Luminance from T2 of CHILESCOPE + RGB from my previous pictures
That's a lovely picture, Iaffaldano, but I'm not sure what you mean by changing the title (of the APOD?).

Ann
Color Commentator

Iaffaldano Giuseppe Carmine
Ensign
Posts: 54
Joined: Sun Jun 18, 2017 10:13 am
Location: TARANTO

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Iaffaldano Giuseppe Carmine » Tue May 10, 2022 10:06 am

i am not practiced and able with software but if you see my post of March 2 2020 you can see that the title of my post was NGC 3521 Galaxy in a Bubble and you give me a kind appraciation; now after 2 years you give apod to a picture that Bubble doesn't show but shows the tidal stream; so if you want give apod to the Bubble give apod to me....... or change the title .....i joke..obviously

Iaffaldano Giuseppe Carmine
Ensign
Posts: 54
Joined: Sun Jun 18, 2017 10:13 am
Location: TARANTO

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Iaffaldano Giuseppe Carmine » Tue May 10, 2022 10:21 am


User avatar
johnnydeep
Captain
Posts: 1491
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by johnnydeep » Tue May 10, 2022 1:24 pm

Iaffaldano Giuseppe Carmine wrote: Tue May 10, 2022 10:06 am i am not practiced and able with software but if you see my post of March 2 2020 you can see that the title of my post was NGC 3521 Galaxy in a Bubble and you give me a kind appraciation; now after 2 years you give apod to a picture that Bubble doesn't show but shows the tidal stream; so if you want give apod to the Bubble give apod to me....... or change the title .....i joke..obviously
Well, I didn't get the joke either, but I guess it has to do with a "first use" claim to using "Galaxy in a Bubble" as a title. In any event, jokes are best indicated as such by using an emoji, or "smiley", like this one: :ssmile: That serves as a clue to the humor challenged.

Regardless of all that, your picture of NGC 3521 is indeed lovely!
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1514
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by JohnD » Tue May 10, 2022 1:58 pm

Be honoured, Iaffaldeno!

As Oscar said, "“Imitation is the sincerest form of flattery that mediocrity can pay to greatness.”

Iaffaldano Giuseppe Carmine
Ensign
Posts: 54
Joined: Sun Jun 18, 2017 10:13 am
Location: TARANTO

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Iaffaldano Giuseppe Carmine » Tue May 10, 2022 4:46 pm

My name is Iaffaldano ..... i don't know Oscar ...who is? I certainly don't imitate anyone; i think that whoever gave to this Apod this title suffers from limited vision and poor imagination or it is possible that my image stayed in his mind. Much better the title given by Hanson : Marquise in the sky https://www.hansonastronomy.com/ngc3521-1meter

User avatar
johnnydeep
Captain
Posts: 1491
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by johnnydeep » Tue May 10, 2022 7:48 pm

Iaffaldano Giuseppe Carmine wrote: Tue May 10, 2022 4:46 pm My name is Iaffaldano ..... i don't know Oscar ...who is? I certainly don't imitate anyone; i think that whoever gave to this Apod this title suffers from limited vision and poor imagination or it is possible that my image stayed in his mind. Much better the title given by Hanson : Marquise in the sky https://www.hansonastronomy.com/ngc3521-1meter
"Oscar" is Oscar Wilde, famous Irish writer and wry wit extraordinaire. For more on his quote:
https://thewordcounter.com/what-does-imitation-is-the-sincerest-form-of-flattery-mean/ wrote: <b>The Origin of the Expression</b>
The cleric and writer Charles Caleb Colton appears to be the first person to have stated the saying exactly as we know and use it today, in his 1820 work Lacon: Or, Many Things in Few Words. But the idea shared by the phrase was expressed before then. Versions of the popular saying conveying the same thought can be found in works from the 1700s, including a biography of Marcus Aurelius and a piece by the writer and politician Eustace Budgell, in which he said, “Imitation is a kind of artless flattery.” Although artless sounds negative in this context, because Budgell’s statement does seem to have inspired the phrase we use today, the adjective likely has more to do with the idea that one can imitate without even being aware they’re doing so, making the imitation a pure or sincere form of flattery.
...
The Irish poet Oscar Wilde weighed in on the debate, elaborating on the proverb and concluding, “Imitation is the sincerest form of flattery that mediocrity can pay to greatness.”

Though to some the truthfulness of the saying is in question, as a proverb, it serves to express a universal idea: that in general, imitation conveys some sense of admiration.
As for where the APOD writers came up with the title, perhaps they were inspired by the one in this page from 2019, which predates your use of the title:

"NGC3521: The Bubble Galaxy"

https://astrodrudis.com/ngc-3521-the-bubble-galaxy/

I'd post the pic itself, but it's huge, so here are just the details of it from the site (also as a pic since cut-and-paste from the site itself is verbotten!

the bubble galaxy pic details.JPG

[ PS - feeling inspired by Neufer today... ]
You do not have the required permissions to view the files attached to this post.
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."

Iaffaldano Giuseppe Carmine
Ensign
Posts: 54
Joined: Sun Jun 18, 2017 10:13 am
Location: TARANTO

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by Iaffaldano Giuseppe Carmine » Wed May 11, 2022 7:32 am

generally as an Italian I am more accustomed to the writings of Dante Alighieri and Alessandro Manzoni, but I prefer my simple paraphrases born from my humble mind to the famous phrases of other minds; if there is a bubble around this galaxy my bubble is the most beautiful ... remember that.

User avatar
johnnydeep
Captain
Posts: 1491
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: NGC 3521: Galaxy in a Bubble (2022 May 05)

Post by johnnydeep » Wed May 11, 2022 2:01 pm

Iaffaldano Giuseppe Carmine wrote: Wed May 11, 2022 7:32 am generally as an Italian I am more accustomed to the writings of Dante Alighieri and Alessandro Manzoni, but I prefer my simple paraphrases born from my humble mind to the famous phrases of other minds; if there is a bubble around this galaxy my bubble is the most beautiful ... remember that.
Well, that doesn't seem very "humble" of you! :ssmile:
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."