APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

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APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by APOD Robot » Tue Jul 23, 2019 4:07 am

Image M82: Galaxy with a Supergalactic Wind

Explanation: Why is the Cigar Galaxy billowing red smoke? M82, as this starburst galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas and dust, however. Evidence indicates that this gas and dust is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind. The dust particles are thought to originate in M82's interstellar medium and are actually similar in size to particles in cigar smoke. The featured photographic mosaic highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas and dust. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, and can be seen in visible light with a small telescope towards the constellation of the Great Bear (Ursa Major).

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by Ann » Tue Jul 23, 2019 7:34 am

A comparison between the original Hubble image and processing, and the processing of the Hubble data made by Daniel Nobre:

NASA, ESA and the Hubble Heritage Team (STScI/AURA).
Acknowledgement: J. Gallagher and P. Puxley.
M82. NASA, ESA, Hubble;
Processing & Copyright: Daniel Nobre





















The difference between the two versions of the picture is that the "body" of M82 is darker blue in Daniel Nobre's picture, and, more importantly, Daniel Nobre's picture appears to show us sites of recent star formation and massive clusters. Note the bright yellowish patch in Nobre's picture, which clearly suggests the presence of massive young clusters, and the bright blue patches to the left of the massive red outflows. These light blue patches again suggests that massive young clusters are present.

However, I believe that M82 is almost completely devoid of star formation except in the center, where a brilliant starburst is taking place. As the APOD caption said, it is this starburst that is fuelling the massive gaseous outflows from the center of M82.

To show you why I don't think that M82 has any star formation to speak of outside of its center, take a look at the GALEX image below of M82. Blue colors in GALEX images mean the presence of far ultraviolet light; yellow colors mean near ultraviolet light usually generated by intermediate-temperature stars of spectral classes F, G and K.

Take a look at M82 and note the all-yellow color of the "body" of the galaxy. The red outflows from the galaxy look blue in the GALEX image, because ultraviolet light is also present in the outflows. Admittedly the three light blue blobs to the left of the outflows that stand out so clearly in Daniel Nobre's image can also be seen in the GALEX picture, now as three (or four) yellow blobs. They might be young clusters, so reddened by dust that they look like old stars in the GALEX image. Just as likely though, they might be "Baade's Windows", regions of the disk of M82 where there is comparatively little dust, and where the (old) stellar population shows up better.

M82 GALEX.png

My point is that I think that the violent outflows of gas from the center of M82, driven by the extreme star formation in the center of that galaxy, is depleting the galaxy of gas and preventing future star formation.

One more note: The caption of the APOD said that the outflows of M82 are over 10.000 light-years long. But if the outflows are 10,000 light-years long, and they appear to be almost as long as the galaxy itself, then I have to wonder how small M82 really is.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by Boomer12k » Tue Jul 23, 2019 8:31 am

Evidently it has had a lot of gas disrupted maybe from brushes with M81...there does not seem to be much gas INSIDE M82...or it would show up in the image as it was specifically photographed.

Not disputing the gas being pushed out...

It is like the, other-wise, DUST LANES are being ripped off M82...

If you look deep, you can see that M82 appears to be spiral...disrupted in places...but a near edge-on...but it is hidden behind all that dust and gas...

It would be interesting to see one of those MAGNETIC images of M82 and how much, if any, magnetic fields influence this.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by Ann » Tue Jul 23, 2019 8:49 am

There is a lot of dust in M82. Last time I checked, M82 was 5 magnitudes brighter in infrared than in blue light. That's a lot!

I get the impression that the surface brightness of M82 is quite high, too. Of course, we see the galaxy edge on, and most edge-on galaxies look bright.

And Boomer, like you said, M82 is actually a spiral galaxy. Apparently the spiral arms of M82 can be seen in infrared light. I have read about it, but I'm too lazy to google it now.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by orin stepanek » Tue Jul 23, 2019 10:51 am

to me; it looks like the dust is it's own entity and not a true part of M82! :shock:
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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by De58te » Tue Jul 23, 2019 11:42 am

Ann wrote:
Tue Jul 23, 2019 7:34 am


One more note: The caption of the APOD said that the outflows of M82 are over 10.000 light-years long. But if the outflows are 10,000 light-years long, and they appear to be almost as long as the galaxy itself, then I have to wonder how small M82 really is.

Ann
Wikipedia said about ~37,000 ly in diameter. Which kinda makes sense if a filament is 10,000 ly long then the combined top and bottom filaments are ~ 20,000 light years long, and if you hold your fingers over it on the computer screen and compare to the length of the galaxy it is about 2/3rds. To me the outflows don't look as long as the galaxy.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by TheOtherBruce » Tue Jul 23, 2019 3:42 pm

An interesting "illumination" effect here. It looks as if the red outflow is being lit up by the bright galactic core, but the plumes of gas and dust are wider than the light cones shining out to galactic north and south, leaving some of the red stuff lit only by the dimmer spiral arms. I wonder if this is a genuine effect, or is something else going on here? That core must be very bright.

I was also intrigued by the mention of a near pass with M81. Any guesstimates how long ago this might have been? I found a wider photo of the whole group they're a part of, and the two galaxies are separated by several diameters.
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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by neufer » Tue Jul 23, 2019 4:00 pm

TheOtherBruce wrote:
Tue Jul 23, 2019 3:42 pm

I was also intrigued by the mention of a near pass with M81. Any guesstimates how long ago this might have been? I found a wider photo of the whole group they're a part of, and the two galaxies are separated by several diameters.
https://en.wikipedia.org/wiki/Messier_82#Starbursts wrote:
<<M82 has undergone at least one tidal encounter with M81 resulting in a large amount of gas being funneled into the galaxy's core over the last 200 Myr. The most recent such encounter is thought to have happened around 2–5×108 years ago and resulted in a concentrated starburst together with a corresponding marked peak in the cluster age distribution. This starburst ran for up to ~50 Myr at a rate of ~10 M per year. Two subsequent starbursts followed, the last (~4–6 Myr ago) of which may have formed the core clusters, both super star clusters (SSCs) and their lighter counterparts.

Stars in M82's disk seem to have been formed in a burst 500 million years ago, leaving its disk littered with hundreds of clusters with properties similar to globular clusters (but younger), and stopped 100 million years ago with no star formation taking place in this galaxy outside the central starburst and, at low levels since 1 billion years ago, on its halo. A suggestion to explain those features is that M82 was previously a low surface brightness galaxy where star formation was triggered due to interactions with its giant neighbor.

Ignoring any difference in their respective distances from the Earth, the centers of M81 and M82 are visually separated by about 130,000 light-years. The actual separation is 300+300−200 kly.>>
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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by starsurfer » Tue Jul 23, 2019 4:06 pm

Click to play embedded YouTube video.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by Cousin Ricky » Tue Jul 23, 2019 4:33 pm

APOD Robot wrote:
Tue Jul 23, 2019 4:07 am
The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, ...
Presumably, the brightest galaxy other than the Milky Way.

In which frequency ranges? Near IF? Far IF? All infrared all-sky images I’ve see are in galactic coordinates using the Mollweide or similar projection. Looking at an all-sky map in galactic coordinates, M82 is towards the upper left, yet I don’t see any bright spots in that area on any infrared all-sky images I can find.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by Ann » Tue Jul 23, 2019 5:14 pm

Cousin Ricky wrote:
Tue Jul 23, 2019 4:33 pm
APOD Robot wrote:
Tue Jul 23, 2019 4:07 am
The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, ...
Presumably, the brightest galaxy other than the Milky Way.

In which frequency ranges? Near IF? Far IF? All infrared all-sky images I’ve see are in galactic coordinates using the Mollweide or similar projection. Looking at an all-sky map in galactic coordinates, M82 is towards the upper left, yet I don’t see any bright spots in that area on any infrared all-sky images I can find.
All I can say about it is that M82 is very infrared, and that it has a high surface brightness. I like to compare the B magnitude of a galaxy with its infrared magnitude. For spiral galaxies, the B magnitude and the infrared magnitude are often similar, at least in the catalogues I'm using.

If a galaxy is brighter in the infrared than in blue light, that typically means that this galaxy is very dusty, but it often also means that the galaxy is undergoing a lot of star formation. If the galaxy is much fainter in infrared than in blue light, that usually means that little star formation is taking place.

Check out the B and far infrared magnitudes of a couple of well-known galaxies:
'
M31: B = 4.3. Far infrared = 5.7. M31 is more than a magnitude fainter in far infrared than in blue light.

M33: B = 6.3. Far infrared = 6.3. M33 is about equally bright in blue and in infrared light.

M81: B = 7.8. Far infrared = 8.6. M81 is fainter in far infrared than in blue light.

M82: B = 9.2. Far infrared: 5.6. M82 is 3.8 magnitudes brighter in far infrared than in blue light.

M82 is also brighter in far infrared light than any other galaxy in the Earth's skies, brighter than Andromeda. Note that we don't know the infrared brightness of our own galaxy, or at least I don't think we do.

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Re: APOD: M82: Galaxy with a Supergalactic Wind (2019 Jul 23)

Post by neufer » Tue Jul 23, 2019 7:02 pm

https://en.wikipedia.org/wiki/Pig-Pen wrote:

<<"Pig-Pen" is a character in the comic strip Peanuts by Charles M. Schulz. Whilst amiable, he is a young boy who is, except on rare occasions, extremely dirty and attracts a permanent cloud of dust. In the character's first appearance on July 13, 1954, in a strip directly parodying the first chapter of Lord of the Flies, he declares, "I haven't got a name ... people just call me things ... real insulting things." If he does have a real name, it is never mentioned.

"Pig-Pen" is known for his perpetually filthy overalls and the cloud of dirt and dust that follows him wherever he goes. When he takes a deep breath (to sing, for example), the dust rises briefly around him. He sometimes refers to the cloud that surrounds him with pride as "the dust of ancient civilizations". He cannot seem to rid himself of the dust for more than the very briefest of periods — indeed, in spite of his best efforts, it appears that he cannot stay clean. He is referred to in an early strip as the only person who can get dirty while walking in a snowstorm. Nevertheless, on rare occasions he has briefly appeared clean, and hence unrecognizable. Once this was in order to impress Violet, of whom he was a bit fond. On another occasion (September 6, 1954), he managed to keep one side of his body clean and presented this clean side to Patty, causing her to believe that he was completely clean.

Once, after bathing and dressing in clean clothes, "Pig-Pen" stepped outside his house, and instantaneously became dirty and disheveled, whereupon he declared to Charlie Brown, "You know what I am? I'm a dust magnet!" On another occasion, "Pig-Pen" decided it was important to have clean hands, but after failing to wash them, realized that he had "reached a point of no return."

Charlie Brown: Don't think of it as dust. Just think of it as the dirt and dust of far-off lands blowing over here and settling on "Pig-Pen!" It staggers the imagination! He may be carrying the soil that was trod upon by Solomon or Nebuchadnezzar or Genghis Khan!>>
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