APOD: Infrared Portrait of the Large Cloud... (2013 Mar 23)

[APOD Robot]

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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[bystander]

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

[Boomer12k]

Too....much....information....head.....going to.....explode!!!!!

What an intriguing picture. I see so many shapes. Monsters and the like, but the most interesting is the Anime Cat Pirate Lady!!!! Where the Tarantula Nebula is. The brightest area is her body, above that is her head, wearing a hat. In her left hand, is a dagger, or pistol. She is holding it up. Her right arm reaches down and pets her cat. All as she sits on a toad stool...absolutely fascinating!!!

:---[===] *

[Ann]

Boomer12k, I never look at astroimages that way! But I like it. I can barely spot your Anime Cat Lady Pirate, but I think I can really see a cat at nine o'clock in this image. Its head is outstretched to the left and held sideways. We can see its eyes and some white above its eyes, and I think I can spot its ears, too. And at about five o'clock I can see a big, dark wolf. I can see its open jaws, two large, misshapen ears, and one, perhaps two, glowing white eyes!

What I really see when I look at a picture like this, however, is how round the Large Magellanic Cloud really is. In visual light, it is so easy to focus on the prominent bar of the LMC and of course on the magnificent Tarantula Nebula. Spiral and irregular galaxies easily look like bright non-spherical structures with a lot of emptiness between the bright parts:

But the empty parts are not empty, just not very luminous. Today's APOD brings out all the non-luminous dust that permeates the large conglomerate of dark and baryonic matter that is the Large Magellanic Cloud. The bright and brilliant stars and nebulae are really just like foam on a large, deep sea.

One thing we can't see in today's APOD is the prominent bar of the LMC. Galactic bars are typically made up of old or at least intermediate stars, and there is usually little dust in the bar. A typical feature of barred galaxies, however, is an enhanced rate of star formation at or near the ends of the bar. The incredible star cluster R136 and the fantastic Tarantula Nebula are perfect examples of enhanced star formation near one end of a galactic bar, and the Tarantula Nebula region does indeed show up well in the infrared picture. Gas and dust are being funneled to the end of the bar, where it accumulates, leading to enhanced star formation. This dust shows up well in infrared images. But the star formation in itself also creates dust, making regions of star formation very dusty and easy to spot in infrared images.

Ann

[MargaritaMc]

I was about to ask what the small blue dots were, but - following the links in the Apod text - I found the answer!
http://www.spitzer.caltech.edu/images/4 ... pace-Cloud

The colors in this image indicate temperatures in the dust that permeates the Cloud. Colder regions show where star formation is at its earliest stages or is shut off, while warm expanses point to new stars heating surrounding dust. The coolest areas and objects appear in red, corresponding to infrared light taken up by Herschel's Spectral and Photometric Imaging Receiver at 250 microns, or millionths of a meter. Herschel's Photodetector Array Camera and Spectrometer fills out the mid-temperature bands, shown here in green, at 100 and 160 microns. The warmest spots appear in blue, courtesy of 24- and 70-micron data from Spitzer.

By the way, I can't see any cats, pirates, or whatever! To me it is a huge and beautiful chrysanthemum.
Margarita

[Lordcat Darkstar]

Is that a dust bunny at the lower right? Better run rabbit or the anime cat will get you.

[Bionic]

A bar like structure is evident in the Herschel image. However, this appears to be a very dynamic structure similar to a wind swept cloud of gas and dust. Bar structure in galaxies are probably the result of density differentials in galaxy disk; dust and gas encountering high density clouds slow down and eventually fall into the galactic core region producing the elongated bar structure. Once in the vicinity of the galactic core the particles respond to new equilibriae, thereby producing a bright inner spiral similar to the kind found in M100.
The mechanics of bar structure in galaxies was obvious even before Hubble Space Telescope deployment. Hubble images only verified what was self evident.
It is unfortunate that the Herschel Space Telescope is a use-and-throw-away facility. Recycling of hardware and precious materials is as much a part of scientific study as it is of daily townsfolk routine. The abandonment of scientific instruments after use is absolutely abhorable and summons an ancient theme concering the environment --> use only that which you can recycle.

[irenebaron]

Excellent infrared image. Does anyone know of an analysis illustrating the direction and speed of the particles in this small galaxy?

[Chris Peterson]

It is unfortunate that the Herschel Space Telescope is a use-and-throw-away facility. Recycling of hardware and precious materials is as much a part of scientific study as it is of daily townsfolk routine. The abandonment of scientific instruments after use is absolutely abhorable and summons an ancient theme concering the environment --> use only that which you can recycle.

Recycling makes little sense when the cost of that recycling exceeds the cost of using new materials by several orders of magnitude.

We have only to look at the HST, which was designed to be repaired. That poor decision reduced the utility of the telescope by requiring it to be in a less than ideal orbit, as well as by sucking up in repair costs the money that could have been used to build two or three additional telescopes.

The cost that would have been incurred in making the Herschel Observatory repairable, recyclable, or extendable would have prevented the mission from ever being launched in the first place.

[neufer]

It is unfortunate that the Herschel Space Telescope is a use-and-throw-away facility. Recycling of hardware and precious materials is as much a part of scientific study as it is of daily townsfolk routine. The abandonment of scientific instruments after use is absolutely abhorable and summons an ancient theme concering the environment --> use only that which you can recycle.

Recycling makes little sense when the cost of that recycling exceeds the cost of using new materials by several orders of magnitude. We have only to look at the HST, which was designed to be repaired. That poor decision reduced the utility of the telescope by requiring it to be in a less than ideal orbit, as well as by sucking up in repair costs the money that could have been used to build two or three additional telescopes.

The cost that would have been incurred in making the Herschel Observatory repairable, recyclable, or extendable would have prevented the mission from ever being launched in the first place.

All spacecraft wear out and/or become obsolete; however, the Herschel Space Observatory
basically just ran out of it's 2,000-litre 3-4 year supply of liquid helium 4 coolant.

Hopefully its replacement [and Planck's replacement which required helium 3 (one tank) and helium 4 (three tanks) at pressures of up to 295 bar for detector temperatures of 0.1K] might allow for some sort of automated refueling procedure.

<<The Herschel Space Observatory is a European Space Agency space observatory sensitive to the far infrared and submillimetre wavebands (55-672 µm). It is the largest infrared space telescope ever launched, carrying a single mirror of 3.5 metres in diameter. Herschel is in its final months, it is hoped its coolant will last until March 2013. The observatory was carried into orbit in May 2009, reaching the second Lagrangian point (L2) of the Earth-Sun system, 1,500,000 kilometres from the Earth, about two months later. Herschel is named after Sir William Herschel, the discoverer of the infrared spectrum and planet Uranus, and his sister and collaborator Caroline Herschel.

The Herschel Observatory is capable of seeing the coldest and dustiest objects in space; for example, cool cocoons where stars form and dusty galaxies just starting to bulk up with new stars. The observatory will sift through star-forming clouds—the "slow cookers" of star ingredients—to trace the path by which potentially life-forming molecules, such as water, form. The United States through NASA is participating in the ESA-built and -operated observatory. It is the fourth 'cornerstone' mission in the ESA science program, along with Rosetta, Planck, and the Gaia mission.

The mission involves the first space observatory to cover the full far infrared and submillimetre waveband. At 3.5 meters wide, its telescope incorporates the largest mirror (made not from glass but from sintered silicon carbide) ever deployed in space. The mirror was ground and polished by Opteon Ltd. in Tuorla Observatory, Finland. The light is focused onto three instruments with detectors kept at temperatures below 2 K (−271 °C). The instruments are cooled with liquid helium, boiling away in a near vacuum at a temperature of approximately 1.4 K (−272 °C). The 2,000-litre supply of helium on board the spacecraft will limit its operational lifetime; nonetheless, it is expected to be operational for at least 3 years.>>

[Boomer12k]

Boomer12k, I never look at astroimages that way! But I like it. I can barely spot your Anime Cat Lady Pirate, but I think I can really see a cat at nine o'clock in this image. Its head is outstretched to the left and held sideways. We can see its eyes and some white above its eyes, and I think I can spot its ears, too. And at about five o'clock I can see a big, dark wolf. I can see its open jaws, two large, misshapen ears, and one, perhaps two, glowing white eyes!

What I really see when I look at a picture like this, however, is how round the Large Magellanic Cloud really is. In visual light, it is so easy to focus on the prominent bar of the LMC and of course on the magnificent Tarantula Nebula. Spiral and irregular galaxies easily look like bright non-spherical structures with a lot of emptiness between the bright parts:

But the empty parts are not empty, just not very luminous. Today's APOD brings out all the non-luminous dust that permeates the large conglomerate of dark and baryonic matter that is the Large Magellanic Cloud. The bright and brilliant stars and nebulae are really just like foam on a large, deep sea.

One thing we can't see in today's APOD is the prominent bar of the LMC. Galactic bars are typically made up of old or at least intermediate stars, and there is usually little dust in the bar. A typical feature of barred galaxies, however, is an enhanced rate of star formation at or near the ends of the bar. The incredible star cluster R136 and the fantastic Tarantula Nebula are perfect examples of enhanced star formation near one end of a galactic bar, and the Tarantula Nebula region does indeed show up well in the infrared picture. Gas and dust are being funneled to the end of the bar, where it accumulates, leading to enhanced star formation. This dust shows up well in infrared images. But the star formation in itself also creates dust, making regions of star formation very dusty and easy to spot in infrared images.

Ann

And I have learned to appreciate the color....BLUE in pictures. I can see your cat face at Nine O'clock, and the Wolf head at five...it looks like an angry Scooby Doo...

It would be interesting to have a side-by-side with a normal shot of the LMC. Or a mouse hover image, where the other shows up too, to see the contrasts.

:---[===] *

[MargaritaMc]

http://apod.nasa.gov/apod/ap081219.html

To identify the location of the supernova and navigate your way around the many star clusters and nebulae of the LMC, just consult this well-labeled view.

This is a link from a link on today's Apod, but it is SO yummy and useful that I thought I'd post it

---

Note: Other labeled images can be found at:

http://www.eso.org/public/images/eso1021d/
http://www.spacetelescope.org/images/heic1011d/

bystander

[davidlfoster]

OK, which is it? This APOD edition says the LMC is 30,000 light years across and the edition referenced for the optical image says it is 15,000 light years across. Those numbers are pretty different.

[MargaritaMc]

Last edited by bystander on Sat Mar 23, 2013 8:11 pm, edited 2 times in total.
Reason: please, no hot links to images > 400kb (file size)

Sorry about that - it didn't occur to me.

Is there a way of finding out the size of a file for potential hot-linking? I know that if I download an image I can discover the size that way - but is there another way?
Margarita

[neufer]

OK, which is it? This APOD edition says the LMC is 30,000 light years across and the edition referenced for the optical image says it is 15,000 light years across. Those numbers are pretty different.

The APOD referenced for the optical image that says it is 15,000 light years across is in error.
That is the number that APOD's usually uses for the Small Magellanic Cloud:

The Small Magellanic Cloud actually spans 15,000 light-years or so and contains several hundred million stars.

Spanning about 30,000 light-years or so, [the Large Magellanic Cloud (LMC)] is the most massive of the Milky Way's satellite galaxies and is the site of the closest supernova in modern times, SN 1987A.

[bystander]

Is there a way of finding out the size of a file for potential hot-linking? I know that if I download an image I can discover the size that way - but is there another way?

In Firefox, right click on an image and select "View Image Info". With MSIE, right click and select "Properties".

[DavidLeodis]

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.". What area in the image actually is the Tarantula Nebula is however not easily obvious to me! I assume it is the very large bright area to the left but I'm unsure because (at least to me) it does not particularly look spider-like (certainly not like it does in the image brought up through the Tarantula Nebula link).

[davidsaroff]

What is the filamentary and web like structure due to? I've heard "shocks" and "magnetic fields" but it looks like neither.

[Chris Peterson]

What is the filamentary and web like structure due to? I've heard "shocks" and "magnetic fields" but it looks like neither.

All the structure is the product of shock waves. It's possible that magnetic fields influence the direction that some material moves, and therefore indirectly affects the structure, but the filaments themselves are shock fronts.

What would you expect shock fronts to look like?