APOD: Infrared Portrait of the Large Cloud... (2012 Jan 15)

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Expand view Topic review: APOD: Infrared Portrait of the Large Cloud... (2012 Jan 15)

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Beyond » Sat Jan 21, 2012 4:36 pm

Tilt wrote:Catcher's mitt, southpaw.
If you're below the equator, would it be called -northpaw- :?:

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Tilt » Sat Jan 21, 2012 3:01 pm

Catcher's mitt, southpaw.

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by DavidLeodis » Mon Jan 16, 2012 6:31 pm

Thanks to Chris for his post that came in while I was typing my response to Ann's post. I must both type and think what I am going to type faster! :)

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by DavidLeodis » Mon Jan 16, 2012 6:27 pm

Ann wrote:
DavidLeodis wrote:In the explanation it states "this galaxy's well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center". From that I asume therefore that the Tarantula Nebula is the bright area running about between 8 and 9 o'clock, but if so it does cover a very extensive area of the LMC. Is the Tarantula Nebula where I think it is :?: I would appreciate some verification or not. Thanks.
I'd say the Tarantula Nebula is at nine o'clock.

Take a look at this former Astronomy Picture of the Day, which shows a somewhat cropped version of the Large Magellanic Cloud. You can see the Tarantula Nebula at ten o'clock. But there are also several bright pink emission nebulae "below" the Tarantula Nebula. Undoubtedly these emission nebulae also contain a good deal of dust. These dusty nebulae "below" the Tarantula Nebula are what you are seeing at eight o'clock in the infrared image of the LMC on January 15, 2012.

Ann
Thanks Ann. That is appreciated. :)

I can now make out what is likely to be the Tarantula Nebula at where you say. The it "stands out, easily seen here as the brightest region to the left of center" in the APOD explanation (my bold type) is to me at least confusing. :?

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Chris Peterson » Mon Jan 16, 2012 6:24 pm

DavidLeodis wrote:In the explanation it states "this galaxy's well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center". From that I asume therefore that the Tarantula Nebula is the bright area running about between 8 and 9 o'clock, but if so it does cover a very extensive area of the LMC. Is the Tarantula Nebula where I think it is :?: I would appreciate some verification or not. Thanks.
Click to view full size image 1 or image 2
Here are the IR and visible images scaled and aligned, which should help in locating paired structures. Mouse over the visible image to see the IR.

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Ann » Mon Jan 16, 2012 4:54 pm

DavidLeodis wrote:In the explanation it states "this galaxy's well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center". From that I asume therefore that the Tarantula Nebula is the bright area running about between 8 and 9 o'clock, but if so it does cover a very extensive area of the LMC. Is the Tarantula Nebula where I think it is :?: I would appreciate some verification or not. Thanks.
I'd say the Tarantula Nebula is at nine o'clock.

Take a look at this former Astronomy Picture of the Day, which shows a somewhat cropped version of the Large Magellanic Cloud. You can see the Tarantula Nebula at ten o'clock. But there are also several bright pink emission nebulae "below" the Tarantula Nebula. Undoubtedly these emission nebulae also contain a good deal of dust. These dusty nebulae "below" the Tarantula Nebula are what you are seeing at eight o'clock in the infrared image of the LMC on January 15, 2012.

Ann

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by DavidLeodis » Mon Jan 16, 2012 1:32 pm

In the explanation it states "this galaxy's well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center". From that I asume therefore that the Tarantula Nebula is the bright area running about between 8 and 9 o'clock, but if so it does cover a very extensive area of the LMC. Is the Tarantula Nebula where I think it is :?: I would appreciate some verification or not. Thanks.

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by islader2 » Mon Jan 16, 2012 2:49 am

@ ANN {without an "e"} Good guess==again==Ann. Conjectural query: Since the LMC and the SMC are connected by a prominent
bridge that even forms "bridge" stars and both bodies are enclosed in a hydrogen cloud (=and maybe dark matter) could that conjecture impinge on your resolve about the celestial position==angular or flat on to us==about what I would perceive as a single entity, videlicem: the Magellan cloud unit? Thanx. :?:
'



]

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Ann » Mon Jan 16, 2012 2:11 am

PiTHON wrote:
Ann wrote:The Large Magellanic Cloud is a face-on (and therefore round-looking) galaxy.
Appearances can be deceiving. From wikipedia (which has the bracketed references if you're interested): "More recently, this inclined geometry for field stars in the LMC has been confirmed via observations of Cepheids,[14] core helium-burning red clump stars[15] and the tip of the red giant branch.[16] All three of these papers find an inclination of ~35°, where a face-on galaxy has an inclination of 0°."

http://en.wikipedia.org/wiki/Large_Magellanic_Cloud
Interesting. You have to wonder how intrinsically oval the Large Magellanic Cloud must be, if it looks round when it is inclined by 35 degrees.

Ann

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by TNT » Sun Jan 15, 2012 11:23 pm

It looks like Scooby-Doo with flight gear on. :mrgreen:

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Boomer12k » Sun Jan 15, 2012 8:59 pm

Does anybody else see the head of Scoobie Doo in the lower right side? Looks like a neck and head sticking from the outer edge to the inside....

At first I thought I was looking at an explosion. Very interesting. Should have an optical picture of the same size to compare it to.

:---[====] *

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by PiTHON » Sun Jan 15, 2012 5:49 pm

Ann wrote:The Large Magellanic Cloud is a face-on (and therefore round-looking) galaxy.
Appearances can be deceiving. From wikipedia (which has the bracketed references if you're interested): "More recently, this inclined geometry for field stars in the LMC has been confirmed via observations of Cepheids,[14] core helium-burning red clump stars[15] and the tip of the red giant branch.[16] All three of these papers find an inclination of ~35°, where a face-on galaxy has an inclination of 0°."

http://en.wikipedia.org/wiki/Large_Magellanic_Cloud

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Chris Peterson » Sun Jan 15, 2012 3:46 pm

epitalon wrote:Has anyone ever submitted the idea that the Magellanic clouds are emitted from our galaxy ?
What about the idea that spiral galaxies are like garden sprinklers ?
Their bulge or "kernel" would rotate at a fix speed, holding together all of its matter and stars by some force other than gravitation....
And from a pair of jets, the kernel would spit some matter out .
that matter would become loose and its movement would be then governed by gravitation force.
Not very scientific but likely from the visual aspect of galaxies....
Eliptic galaxies would be simply galaxies at rest : maybe rotating but not spitting matter ?
In the absence of an ejection mechanism, there is no reason to believe that the Magellanic Clouds came from our galaxy. And even supposing an unknown mechanism, they are made up of a very different mix of material, and their orbits don't support the idea just looking at the dynamics.

Like the other Local Group galaxies, they appear to have formed by the same processes, and at about the same time, as the Milky Way.

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by epitalon » Sun Jan 15, 2012 1:49 pm

Has anyone ever submitted the idea that the Magellanic clouds are emitted from our galaxy ?
What about the idea that spiral galaxies are like garden sprinklers ?
Their bulge or "kernel" would rotate at a fix speed, holding together all of its matter and stars by some force other than gravitation....
And from a pair of jets, the kernel would spit some matter out .
that matter would become loose and its movement would be then governed by gravitation force.
Not very scientific but likely from the visual aspect of galaxies....
Eliptic galaxies would be simply galaxies at rest : maybe rotating but not spitting matter ?

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Case » Sun Jan 15, 2012 1:36 pm

Bruce333 wrote:"160,000 light-years distant, 30,000 light-years across" doesn't match "180,000 light-years distant, 15,000 light-years across"
It depends on whose research you follow. NED finds 334 (!) distances in literature for the LMC. The lowest is 133,727 ly (0.041 Mpc); the biggest number is 231,576 ly (0.071 Mpc). Statistically NED finds a mean of 163,082 ly (0.050 Mpc) with a standard deviation of 13,047 ly (0.004 Mpc).
Also the width across is not so easy to to pinpoint, as the the 'edges' are fuzzy. (How wide is the 'cloud' in the image below?)
Image
I agree that 30,000 is a long way off from 15,000, though. :)

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by orin stepanek » Sun Jan 15, 2012 1:35 pm

The amount of dust clouds that the infrared picture showed in the LMC was kind of surprising to me. :!: 8-)

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Bruce333 » Sun Jan 15, 2012 11:14 am

Has the LMC suddenly gotten closer and expanded in size?

This:
A mere 160,000 light-years distant, the Large Cloud of Magellan is about 30,000 light-years across.
doesn't match this from a previous APOD:
A mere 180,000 light-years distant....The Large Magellanic Cloud is about 15,000 light-years across.
http://apod.nasa.gov/apod/ap110426.html

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Byork » Sun Jan 15, 2012 10:21 am

i thought todays apod image resembled an egg that was overcooked in a microwave oven..scientific but not very tasty

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Ann » Sun Jan 15, 2012 7:30 am

What I like best about today's APOD is that it underscores the fact that the Large Magellanic Cloud is a face-on galaxy. I disagree with claims that it is any sort of spiral galaxy. Where are the spiral arms?

The Large Magellanic Cloud is a face-on (and therefore round-looking) galaxy. It is a barred galaxy. It has no bulge and no central brightening. Does it have a central black hole? That would seem unlikely.

Since the LMC has a bar but no bulge, this means that bars don't need bulges or central black holes in order to form.

The Large Magellanic Cloud has what appears to be a huge "halo" of stars, most of which are probably old and faint. These stars are old because they were formed long ago and have had plenty of time to spread outwards. It is easy to forget that the LMC has been around as a galaxy for billions of years. According to Sidney van den Bergh's book "The Galaxies of the Local Group", the bar structure of the LMC is 6-7 billion years old, and the oldest globulars in this galaxy are more than 12 billion years old. Admittedly the figures may be somewhat exaggerated, since Sidney van den Bergh is writing his book from the assumption that the universe is more than 15 billion years old. Current understanding says that the universe is less than 14 billion years old, around 13.7 billion years old.

Ann

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Ann » Sun Jan 15, 2012 6:52 am

Hmmm, I was wrong. Since it said yesterday that tomorrow's (today's) APOD would show "a bar and a wing", I expected the Small Magellanic Cloud.
Image
This image shows the Small Magellanic Cloud. The oblong structure on the right, pointing down and to the right, is the bar. The more or less horizontal structure extending to the left of it is the wing. I expected to be shown something like this today.




Ann

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Chris Peterson » Sun Jan 15, 2012 5:49 am

Images like this (especially when compared with the linked visual wavelength image) show why IR imaging is becoming the dominant methodology. There is vastly more information present in the IR image than in any combination of data collected at shorter wavelengths.

Outside of stars, most of the Universe is filled with cool dust. Understanding its distribution and characteristics is key to understanding the Universe itself- and all of this material is largely invisible at wavelengths shorter than IR.

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by bystander » Sun Jan 15, 2012 5:22 am

http://asterisk.apod.com/viewtopic.php?f=31&t=26441

Re: APOD: Infrared Portrait of the Large Cloud... (2012 Jan

by Beyond » Sun Jan 15, 2012 5:19 am

When the image of the cloud first popped up, i thought to myself, that looks very much like a toasted marshmallow. Not very scientific.... but very tasty :!:

APOD: Infrared Portrait of the Large Cloud... (2012 Jan 15)

by APOD Robot » Sun Jan 15, 2012 5:08 am

Image Infrared Portrait of the Large Magellanic Cloud

Explanation: Cosmic dust clouds ripple across this infrared portrait of our Milky Way's satellite galaxy, the Large Magellanic Cloud. In fact, the remarkable composite image from the Herschel Space Observatory and the Spitzer Space Telescope show that dust clouds fill this neighboring dwarf galaxy, much like dust along the plane of the Milky Way itself. The dust temperatures tend to trace star forming activity. Spitzer data in blue hues indicate warm dust heated by young stars. Herschel's instruments contributed the image data shown in red and green, revealing dust emission from cooler and intermediate regions where star formation is just beginning or has stopped. Dominated by dust emission, the Large Magellanic Cloud's infrared appearance is different from views in optical images. But this galaxy's well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center. A mere 160,000 light-years distant, the Large Cloud of Magellan is about 30,000 light-years across.

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