APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

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APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by APOD Robot » Thu May 02, 2024 4:06 am

Image M100: A Grand Design Spiral Galaxy

Explanation: Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. The large galaxy of over 100 billion stars has well-defined spiral arms, similar to our own Milky Way. One of the brightest members of the Virgo Cluster of galaxies, M100, also known as NGC 4321 is 56 million light-years distant toward the well-groomed constellation Coma Berenices. In this telescopic image, the face-on grand design spiral shares a nearly 1 degree wide field-of-view with slightly less conspicuous edge-on spiral NGC 4312 (at upper right). The 21 hour long equivalent exposure from a dark sky site near Flagstaff, Arizona, planet Earth, reveals M100's bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Measurements of variable stars in M100 have played an important role in determining the size and age of the Universe.

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by DJE44 » Thu May 02, 2024 4:53 am

Thank you very much. Extremely honored again. 🙏🏼

I am blessed with Bortle 2 skies in Northern Arizona.

-Drew

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Thu May 02, 2024 5:01 am

DJE44 wrote: Thu May 02, 2024 4:53 am Thank you very much. Extremely honored again. 🙏🏼

I am blessed with Bortle 2 skies in Northern Arizona.

-Drew

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Absolutely superb image, Drew! :D :thumb_up: :clap:

I'll try to comment on it (and on galaxy M100 in general) later today, but I have no time now.

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by DJE44 » Thu May 02, 2024 5:50 am

Thank you Ann!

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Christian G. » Thu May 02, 2024 11:47 am

DJE44 wrote: Thu May 02, 2024 4:53 am I am blessed with Bortle 2 skies in Northern Arizona.
And we're blessed with the fruits of your hard work! Beautiful image...

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Rauf » Thu May 02, 2024 11:52 am

DJE44 wrote: Thu May 02, 2024 4:53 am Thank you very much. Extremely honored again. 🙏🏼

I am blessed with Bortle 2 skies in Northern Arizona.

-Drew

https://www.astrobin.com/users/DrewJEvans/
https://NAZObservatory.com
Excellent work!
Can I ask how many hours did you spend creating this picture in total?

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by johnnydeep » Thu May 02, 2024 1:26 pm

Rauf wrote: Thu May 02, 2024 11:52 am
DJE44 wrote: Thu May 02, 2024 4:53 am Thank you very much. Extremely honored again. 🙏🏼

I am blessed with Bortle 2 skies in Northern Arizona.

-Drew

https://www.astrobin.com/users/DrewJEvans/
https://NAZObservatory.com
Excellent work!
Can I ask how many hours did you spend creating this picture in total?
The link to the author's Astrobin page has this info:
Dates:
March 8, 2024
April 1 - 4, 2024
April 10, 2024
April 15 - 16, 2024

Frames:
Antlia ALP-T Dual Band 5nm 2": 51×300″(4h 15′)
Astronomik L-3 Luminance UV/IR Block 2": 200×300″(16h 40′)
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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Guest » Thu May 02, 2024 3:30 pm

Rauf wrote: Thu May 02, 2024 11:52 am Excellent work!
Can I ask how many hours did you spend creating this picture in total?
Thank you! 21 hours to be precise.

https://www.astrobin.com/hzakye/

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Guest » Thu May 02, 2024 3:31 pm

Christian G. wrote: Thu May 02, 2024 11:47 am And we're blessed with the fruits of your hard work! Beautiful image...
🙏🏼 much appreciated

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Rauf » Thu May 02, 2024 4:21 pm

Guest wrote: Thu May 02, 2024 3:30 pm
Rauf wrote: Thu May 02, 2024 11:52 am Excellent work!
Can I ask how many hours did you spend creating this picture in total?
Thank you! 21 hours to be precise.

https://www.astrobin.com/hzakye/
I see! But how many hours did the processing take? It can't be 21 hours for the entire effort, right?

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by DJE44 » Thu May 02, 2024 4:32 pm

Rauf wrote: Thu May 02, 2024 4:21 pm
Guest wrote: Thu May 02, 2024 3:30 pm
Rauf wrote: Thu May 02, 2024 11:52 am Excellent work!
Can I ask how many hours did you spend creating this picture in total?
Thank you! 21 hours to be precise.

https://www.astrobin.com/hzakye/
I see! But how many hours did the processing take? It can't be 21 hours for the entire effort, right?
Data acquisition was 21 hours. Processing was done in APP and Pixinsight, not much over an hour.

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Rauf » Thu May 02, 2024 4:33 pm

DJE44 wrote: Thu May 02, 2024 4:32 pm
Rauf wrote: Thu May 02, 2024 4:21 pm
Guest wrote: Thu May 02, 2024 3:30 pm

Thank you! 21 hours to be precise.

https://www.astrobin.com/hzakye/
I see! But how many hours did the processing take? It can't be 21 hours for the entire effort, right?
Data acquisition was 21 hours. Processing was done in APP and Pixinsight, not much over an hour.
Wow. I thought it takes longer than that! Thanks for answering :ssmile:

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by johnnydeep » Thu May 02, 2024 4:39 pm

Sadly, this "One of the brightest members of the Virgo Cluster of galaxies, M100, also known as NGC 4321" is not even shown at the Virgo Cluster APOD link:

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by smitty » Thu May 02, 2024 5:00 pm

Am I correct in thinking that M100 is not a "barred" galaxy? And if so, do we understand why some galaxies are barred and others are not?

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Thu May 02, 2024 6:32 pm

Okay, I'm finally ready to talk about today's splendid APOD, and I don't really know where to start. Let's start with an annotated version of the APOD!

APOD 2 May 2024 annotated.png
Majestic grand design galaxy M100 and friends.
Credit: Drew Evans.

M100 is surrounded by a lot of friends, or satellite galaxies. The two most important are NGC 4322 and NGC 4328. They are, in some ways, to M100 what the Magellanic Clouds are to the Milky Way:


If you ask me, NGC 4322 and NGC 4328 probably help shape the beautiful spiral arms of M100, and the Magellanic Clouds are possibly doing the same thing for our own galaxy. Of course, a huge difference is that the Magellanic Clouds are blue and pink from fresh star formation👶, whereas NGC 4322 and NGC 4328 are tired and yellow from geriatric stars only. 👴 NGC 4322 and NGC 4328 may have orbited M100 for a long time and thus lost their gas and their ability to form new stars, whereas the Magellanic Clouds have only recently been captured by the Milky Way, and they - or at least the LMC - is going to collide with our galaxy!!! Yikes!!!
💥 :shock:

Sci News wrote:

The Large Magellanic Cloud, a dwarf galaxy located approximately 163,000 light-years away, is on a collision course with the Milky Way with which it will merge in about 2.4 billion years, according to new research. This catastrophic event could wake up our Galaxy’s dormant supermassive black hole, which would begin devouring surrounding gas and increase in size by up to 8 times; the Milky Way’s stellar halo will undergo an equally impressive transformation, becoming 5 times more massive; the merger will also gravitationally eject central disk stars into the halo.
😮 😲


I don't know what plans NGC 4322 has for M100, but it is sitting inside the outer halo of M100, looking innocent 👼🏻 and nucleated! (That is, it has a nucleus.)


So let's talk about M100 itself, shall we?

M100 Drew Evans.png

The core of M100 is brilliant from a great starburst:


The inner disk of M100 is yellow from old stars, but its two majestic arms are blue. The inner arms shine from a mixture of blue star clusters and pink emission nebulas. But the spiral structure continues even after the blue arms end, now as broad spiral arms made of old, yellowish-beige stars. I guess you could say that the halo of M100 is spiral-shaped! 🙂

And did you know that a really titanic supernova exploded in M100 in 1979, SN 1979C? 💥 It is so important that it has its own Wikipedia entry:

Wikipedia wrote:

The Type II supernova was discovered April 19, 1979 by Gus Johnson, a school teacher and amateur astronomer...

The star that resulted in this supernova was estimated to be in the range of 20 solar masses...

On November 15, 2010 NASA announced that evidence of a black hole had been detected as a remnant of the supernova explosion. Scientists led by Dr. Dan Patnaude from the Center for Astrophysics | Harvard & Smithsonian in Cambridge, MA evaluated data gathered between 1995 and 2007 from several space based observatories. NASA's Chandra X-ray Observatory, the Swift Gamma-Ray Burst Mission, as well as the European Space Agency's XMM-Newton, and Germany's ROSAT all participated in the examination.

Okay, so it could be that the remnant is not a black hole but "only" a pulsar wind nebula from a rapidly spinning pulsar, similar to the Crab Nebula.

Whatever! This supernova was bright, by far the brightest that has been observed in M100. But so very little is known about it, because no one - and I mean no one - photographed it back in 1979! No one except James D Wray, who casually snapped a picture of it as he was photographing M100 for his atlas of galaxies!

SN 1979C in M100 James D Wray.jpg
The only picture ever of SN 1979C
from James D Wray's atlas!

Finally, M100 is a galaxy rich in star formation, yet it is a member of the large and rich Virgo Cluster. This would not be possible unless M100 was located on the outskirts of the Virgo Cluster - and it is!

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Thu May 02, 2024 6:55 pm

johnnydeep wrote: Thu May 02, 2024 4:39 pm Sadly, this "One of the brightest members of the Virgo Cluster of galaxies, M100, also known as NGC 4321" is not even shown at the Virgo Cluster APOD link:


That's because M100 is located too far away from the center of the Virgo cluster.


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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Thu May 02, 2024 7:17 pm

smitty wrote: Thu May 02, 2024 5:00 pm Am I correct in thinking that M100 is not a "barred" galaxy? And if so, do we understand why some galaxies are barred and others are not?

Wikipedia called M100 an intermediate spiral galaxy:
Wikipedia wrote:

Messier 100 (also known as NGC 4321 or the Mirror Galaxy) is a grand design intermediate spiral galaxy in the southern part of the mildly northern Coma Berenices.
"Intermediate" in this case means that the galaxy is midway between barred and unbarred galaxies. Take a look at this picture of the central part of M100:


Note the two long, dark dust lanes winding their way from the very nucleus of M100 all the way out to the spiral arms. Such dust lanes are typical of barred galaxies. But the inner bulge of M100 is not elongated, as we would expect from a barred galaxy, and at least one of the spiral arms appears to begin almost at the nucleus.


Let's look at a truly barred galaxy, M61:


As to why some galaxies are barred and others are unbarred, sorry, you will have to ask someone else about that!

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by smitty » Thu May 02, 2024 7:22 pm

Ann, thank you! Appreciate your explanatory details!

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Thu May 02, 2024 7:46 pm

smitty wrote: Thu May 02, 2024 7:22 pm Ann, thank you! Appreciate your explanatory details!
You're welcome! :D

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by johnnydeep » Thu May 02, 2024 9:09 pm

Ann wrote:Let's look at a truly barred galaxy, M61:
Wikipedia thinks M61 is an intermediate barred spiral:
https://en.wikipedia.org/wiki/Messier_61 wrote:Messier 61 (also known as M61, NGC 4303, or the Swelling Spiral Galaxy) is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet.[5] Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.[6]
Also, where's the bar in M61? Is it that ovoid gray dust shape? I'm not really seeing any bar!
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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Fri May 03, 2024 5:18 am

johnnydeep wrote: Thu May 02, 2024 9:09 pm
Ann wrote:Let's look at a truly barred galaxy, M61:
Wikipedia thinks M61 is an intermediate barred spiral:
https://en.wikipedia.org/wiki/Messier_61 wrote:Messier 61 (also known as M61, NGC 4303, or the Swelling Spiral Galaxy) is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet.[5] Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.[6]
Also, where's the bar in M61? Is it that ovoid gray dust shape? I'm not really seeing any bar!

I don't necessarily always trust Wikipedia. I can see the bar in M61.

Let's look at some bars:

Bar in M61 ESA Hubble Gendler.png
Bars in NGC 1365 Bernard Miller.png
Bar in NGC 1300 NASA ESA Hubble Kevin Gill.png

Ann
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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by johnnydeep » Fri May 03, 2024 11:46 am

Ann wrote: Fri May 03, 2024 5:18 am
johnnydeep wrote: Thu May 02, 2024 9:09 pm
Ann wrote:Let's look at a truly barred galaxy, M61:
Wikipedia thinks M61 is an intermediate barred spiral:
https://en.wikipedia.org/wiki/Messier_61 wrote:Messier 61 (also known as M61, NGC 4303, or the Swelling Spiral Galaxy) is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet.[5] Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.[6]
Also, where's the bar in M61? Is it that ovoid gray dust shape? I'm not really seeing any bar!

I don't necessarily always trust Wikipedia. I can see the bar in M61.

Let's look at some bars:

Bar in M61 ESA Hubble Gendler.png
Bars in NGC 1365 Bernard Miller.png
Bar in NGC 1300 NASA ESA Hubble Kevin Gill.png

Ann
Still not much of a definitive bar in M61 at all compared to your other examples. And I'm not convinced of the "inner" bar in NGC 1365 either!

"A bar is in the eye of the beholder" it seems.
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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Ann » Fri May 03, 2024 1:23 pm

johnnydeep wrote: Fri May 03, 2024 11:46 am

Still not much of a definitive bar in M61 at all compared to your other examples. And I'm not convinced of the "inner" bar in NGC 1365 either!

"A bar is in the eye of the beholder" it seems.

I just told you that I don't necessarily always trust Wikipedia, but now I'm going to quote Wikipedia anyway to back up my claim that there are two bars in NGC 1365:

Wikipedia wrote:

NGC 1365 is a large barred spiral galaxy in the Fornax cluster. Within the larger long bar stretching across the center of the galaxy appears to be a smaller bar that comprises the core, with an apparent size of about 50″ × 40″.[3] This second bar is more prominent in infrared images of the central region of the galaxy, and likely arises from a combination of dynamical instabilities of stellar orbits in the region, along with gravity, density waves, and the overall rotation of the disc. The inner bar structure likely rotates as a whole more rapidly than the larger long bar, creating the diagonal shape seen in images.

And I can see the bars of NGC 1365. :wink:

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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by johnnydeep » Fri May 03, 2024 2:17 pm

Ann wrote: Fri May 03, 2024 1:23 pm
johnnydeep wrote: Fri May 03, 2024 11:46 am

Still not much of a definitive bar in M61 at all compared to your other examples. And I'm not convinced of the "inner" bar in NGC 1365 either!

"A bar is in the eye of the beholder" it seems.

I just told you that I don't necessarily always trust Wikipedia, but now I'm going to quote Wikipedia anyway to back up my claim that there are two bars in NGC 1365:

Wikipedia wrote:

NGC 1365 is a large barred spiral galaxy in the Fornax cluster. Within the larger long bar stretching across the center of the galaxy appears to be a smaller bar that comprises the core, with an apparent size of about 50″ × 40″.[3] This second bar is more prominent in infrared images of the central region of the galaxy, and likely arises from a combination of dynamical instabilities of stellar orbits in the region, along with gravity, density waves, and the overall rotation of the disc. The inner bar structure likely rotates as a whole more rapidly than the larger long bar, creating the diagonal shape seen in images.

And I can see the bars of NGC 1365. :wink:

Ann
Is there even a definition of a "bar" based on something other than mere appearance? Is it simply dust/gas that is apparently concentrated more or less predominantly along a line through the galaxy core?
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Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

Post by Chris Peterson » Fri May 03, 2024 2:22 pm

johnnydeep wrote: Fri May 03, 2024 2:17 pm
Ann wrote: Fri May 03, 2024 1:23 pm
johnnydeep wrote: Fri May 03, 2024 11:46 am

Still not much of a definitive bar in M61 at all compared to your other examples. And I'm not convinced of the "inner" bar in NGC 1365 either!

"A bar is in the eye of the beholder" it seems.

I just told you that I don't necessarily always trust Wikipedia, but now I'm going to quote Wikipedia anyway to back up my claim that there are two bars in NGC 1365:

Wikipedia wrote:

NGC 1365 is a large barred spiral galaxy in the Fornax cluster. Within the larger long bar stretching across the center of the galaxy appears to be a smaller bar that comprises the core, with an apparent size of about 50″ × 40″.[3] This second bar is more prominent in infrared images of the central region of the galaxy, and likely arises from a combination of dynamical instabilities of stellar orbits in the region, along with gravity, density waves, and the overall rotation of the disc. The inner bar structure likely rotates as a whole more rapidly than the larger long bar, creating the diagonal shape seen in images.

And I can see the bars of NGC 1365. :wink:

Ann
Is there even a definition of a "bar" based on something other than mere appearance? Is it simply dust/gas that is apparently concentrated more or less predominantly along a line through the galaxy core?
I think it's purely a subjective, visual definition. In a sense, we might argue there is no such thing as a barred or unbarred spiral, merely a continuum between very strong and very weak central resonance structures... states that spiral galaxies appear to oscillate between over billions of years.
Chris

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