APOD: The N44 Superbubble (2017 Jun 25)

APOD Robot · Post by **APOD Robot** » Sun Jun 25, 2017 4:06 am

The N44 Superbubble

Explanation: What created this gigantic hole? The vast emission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250 light-year hole and astronomers are trying to figure out why. One possibility is particle winds expelled by massive stars in the bubble's interior that are pushing out the glowing gas. This answer was found to be inconsistent with measured wind velocities, however. Another possibility is that the expanding shells of old supernovas have sculpted the unusual space cavern. An unexpected clue of hot X-ray emitting gas was recently been detected escaping the N44 superbubble. The featured image was taken in three very specific colors by the huge 8-meter Gemini South Telescope on Cerro Pachon in Chile.

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Boomer12k · Post by **Boomer12k** » Sun Jun 25, 2017 4:45 am

Sort of like our "Local Bubble", where supernova blew out a cavern from the interstellar medium.... And also emits Xrays?

Sort of like that?

:---[===] *

Ann · Post by **Ann** » Sun Jun 25, 2017 5:46 am

Boomer12k wrote:Sort of like our "Local Bubble", where supernova blew out a cavern from the interstellar medium.... And also emits Xrays?

Sort of like that?

:---[===] *

I would think it has something to do with that.

APOD Robot wrote:

Click to view full size image
Huge emission nebula NGC 604 in M33.
Credit: X-ray: NASA / CXC / R. Tuellmann (Harvard-Smithsonian CfA) et al.;
Optical: NASA/AURA/STScI
Some 3 million light-years distant in nearby spiral galaxy M33, giant stellar nursery NGC 604 is about 1,300 light-years across, or nearly 100 times the size of the Orion Nebula. In fact, among the star forming regions within the Local Group of galaxies, NGC 604 is second in size only to 30 Doradus, also known as the Tarantula Nebula in the Large Magellanic Cloud. This space-age color composite of X-ray data (in blue hues) from the Chandra Observatory, and Hubble optical data shows that NGC 604's cavernous bubbles and cavities are filled with a hot, tenuous, X-ray emitting gas. Intriguingly, NGC 604 itself is divided by a wall of relatively cool gas. On the western (right) side of the nebula, measurements indicate that material is likely heated to X-ray temperatures by the energetic winds from a cluster of about 200 young, massive stars. On the eastern side the X-ray filled cavities seem to be older, suggesting supernova explosions from the end of massive star evolution contribute to their formation.

Ann

EDIT: By the way...

starsurfer · Post by **starsurfer** » Sun Jun 25, 2017 10:11 am

So many awesome nebulae in the LMC!

neufer · Post by **neufer** » Sun Jun 25, 2017 11:02 am

http://chandra.harvard.edu/photo/2012/n1929/ wrote:
[c]NGC 1929 in N44: A Surprisingly Bright Superbubble[/c]
[b][size=200][color=#0000FF]X-ray: NASA/CXC/U.Mich./S.Oey,[/color][/size] [size=150][color=#FF0000]IR: NASA/JPL, Optical: ESO/WFI/2.2-m[/color][/size][/b]
[b][color=#0000FF]How does smoker's lungs look like on x-ray?[/color][/b]
<<This composite image shows a superbubble in the Large Magellanic Cloud (LMC), a small satellite galaxy of the Milky Way, located about 160,000 light years from Earth. Many new stars, some of them very massive, are forming in the star cluster NGC 1929, which is embedded in the nebula N44. The massive stars produce intense radiation, expel matter at high speeds, and race through their evolution to explode as supernovas. The winds and supernova shock waves carve out huge cavities called superbubbles in the surrounding gas. X-rays from NASA's Chandra X-ray Observatory (blue) show hot regions created by these winds and shocks, while infrared data from NASA's Spitzer Space Telescope (red) outline where the dust and cooler gas are found. The optical light from the 2.2m Max-Planck-ESO telescope (yellow) in Chile shows where ultraviolet radiation from hot, young stars is causing gas in the nebula to glow.

A long-running problem in high-energy astrophysics has been that some superbubbles in the LMC, including N44, give off a lot more X-rays than expected from models of their structure. A Chandra study published in 2011 showed that there are two extra sources of the bright X-ray emission: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls. The observations show no evidence for an enhancement of elements heavier than hydrogen and helium in the cavities, thus ruling out this possibility as an explanation for the bright X-ray emission. This is the first time that the data have been good enough to distinguish between different sources of the X-rays produced by superbubbles.

The Chandra study of N44 and another superbubble in the LMC was led by Anne Jaskot from the University of Michigan in Ann Arbor. The co-authors were Dave Strickland from Johns Hopkins University in Baltimore, MD, Sally Oey from University of Michigan, You-Hua Chu from University of Illinois and Guillermo Garcia-Segura from Instituto de Astronomia-UNAM in Ensenada, Mexico.>>

: [b][color=#0000FF]The 44th St. smoking Camel cigarette billboard in Times Square (1948)[/color][/b]

https://en.wikipedia.org/wiki/Douglas_Leigh wrote:
<<Douglas Leigh (May 24, 1907 – December 14, 1999) was a pioneer in signage and outdoor advertising at Times Square. He also designed the colored lighting scheme for the Empire State Building.

Leigh's first eye-catching creation was a billboard for A&P, advertising the store's Eight O'Clock Coffee with clouds of steam emanating from a large cup of coffee. A Camel billboard blew smoke rings from a steam generator from the Hotel Claridge at 44th Street, while one for Kool cigarettes featured a blinking penguin. One for Ballantine Beer had clowns tossing quoits on a peg. The Coca-Cola sign at Bryant Park gave an ever-changing weather forecast (featuring a house and pictures of sun, rain, snow, etc.) along with the slogan "Thirst knows no season" (Leigh paid a tenant's weekly laundry bills to stop her from hanging her laundry on her clothesline in front of the sign).>>

Hamadryad · Post by **Hamadryad** » Sun Jun 25, 2017 12:58 pm

This nebula/bubble just begs for a nickname. I nominate the Bad Hair or Wild Hair Nebula.

douglas · Post by **douglas** » Sun Jun 25, 2017 1:11 pm

APOD Robot: "An unexpected clue of hot X-ray emitting gas was recently been detected escaping .. "

Actually, it was expected, and is the first detection of that predicted phenomenon: Sally Oey of the University of Michigan: “Observations from space have even revealed x-ray-emitting gas escaping from this superbubble, and while this is expected, this is the only object of its kind where we have actually seen it happening.”

Philip Massey of Lowell Observatory: “When we look at the speed of the gases in this cloud we find inconsistencies in the size of the bubble and the expected velocities of the winds from the central cluster of massive stars. Supernovae, the ages of the central stars, or the orientation and shape of the cloud might explain this .. " That bolded part is where my bet is.

" .. astronomers do not agree on exactly how this bubble has evolved for up to the past 10 million years .. "
http://www.gemini.edu/node/171

Escaping gas is emitting X-rays, but no compression fronts are emitting comparable amounts? Would not a supernova have expelled that escaping gas upon exploding?

Pair the imaging up with subsequent observing runs like Hubble did with the Veil Nebula. Changes would be likely visible even at N44's distance.

Veil exploded in ~ 3000 B.C. at 2,100 light years distance. (this link claims the Veil supernova "occurred more than 20000 years ago." and the shock fronts are still emitting X-rays https://www.noao.edu/image_gallery/html/im0532.html )

"Few astronomical objects change dramatically in a human's lifetime. We were fortunate that a portion of the 2015 Hubble WFC3 image was observed using Hubble's WFPC2 camera back in 1997. At the tremendous distance of the Cygnus Loop, roughly 2,100 light-years away, subtle motions of several shock fronts are visible over the 18 years span."
http://heritage.stsci.edu/2015/29/supplemental.html

alter-ego · Post by **alter-ego** » Mon Jun 26, 2017 12:16 am

APOD Robot wrote:What created this gigantic hole?

It's a cosmic hole-punch cloud.

Starship Asterisk*

APOD: The N44 Superbubble (2017 Jun 25)

APOD: The N44 Superbubble (2017 Jun 25)

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The 44th Street Super Smoke Ring

Re: APOD: The N44 Superbubble (2017 Jun 25)

Re: APOD: The N44 Superbubble (2017 Jun 25)

Re: APOD: The N44 Superbubble (2017 Jun 25)